trigger.c

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/*-------------------------------------------------------------------------
 *
 * trigger.c
 *    PostgreSQL TRIGGERs support code.
 *
 * Portions Copyright (c) 1996-2026, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 * IDENTIFICATION
 *    src/backend/commands/trigger.c
 *
 *-------------------------------------------------------------------------
 */
#include "postgres.h"
 
#include "access/genam.h"
#include "access/htup_details.h"
#include "access/relation.h"
#include "access/sysattr.h"
#include "access/table.h"
#include "access/tableam.h"
#include "access/tupconvert.h"
#include "access/xact.h"
#include "catalog/catalog.h"
#include "catalog/dependency.h"
#include "catalog/indexing.h"
#include "catalog/objectaccess.h"
#include "catalog/partition.h"
#include "catalog/pg_constraint.h"
#include "catalog/pg_inherits.h"
#include "catalog/pg_proc.h"
#include "catalog/pg_trigger.h"
#include "catalog/pg_type.h"
#include "commands/trigger.h"
#include "executor/executor.h"
#include "executor/instrument.h"
#include "miscadmin.h"
#include "nodes/bitmapset.h"
#include "nodes/makefuncs.h"
#include "optimizer/optimizer.h"
#include "parser/parse_clause.h"
#include "parser/parse_collate.h"
#include "parser/parse_func.h"
#include "parser/parse_relation.h"
#include "partitioning/partdesc.h"
#include "pgstat.h"
#include "rewrite/rewriteHandler.h"
#include "rewrite/rewriteManip.h"
#include "storage/lmgr.h"
#include "utils/acl.h"
#include "utils/builtins.h"
#include "utils/fmgroids.h"
#include "utils/guc_hooks.h"
#include "utils/inval.h"
#include "utils/lsyscache.h"
#include "utils/memutils.h"
#include "utils/plancache.h"
#include "utils/rel.h"
#include "utils/snapmgr.h"
#include "utils/syscache.h"
#include "utils/tuplestore.h"
 
 
/* GUC variables */
int         SessionReplicationRole = SESSION_REPLICATION_ROLE_ORIGIN;
 
/* How many levels deep into trigger execution are we? */
static int  MyTriggerDepth = 0;
 
/* Local function prototypes */
static void renametrig_internal(Relation tgrel, Relation targetrel,
                                HeapTuple trigtup, const char *newname,
                                const char *expected_name);
static void renametrig_partition(Relation tgrel, Oid partitionId,
                                 Oid parentTriggerOid, const char *newname,
                                 const char *expected_name);
static void SetTriggerFlags(TriggerDesc *trigdesc, Trigger *trigger);
static bool GetTupleForTrigger(EState *estate,
                               EPQState *epqstate,
                               ResultRelInfo *relinfo,
                               ItemPointer tid,
                               LockTupleMode lockmode,
                               TupleTableSlot *oldslot,
                               bool do_epq_recheck,
                               TupleTableSlot **epqslot,
                               TM_Result *tmresultp,
                               TM_FailureData *tmfdp);
static bool TriggerEnabled(EState *estate, ResultRelInfo *relinfo,
                           Trigger *trigger, TriggerEvent event,
                           Bitmapset *modifiedCols,
                           TupleTableSlot *oldslot, TupleTableSlot *newslot);
static HeapTuple ExecCallTriggerFunc(TriggerData *trigdata,
                                     int tgindx,
                                     FmgrInfo *finfo,
                                     Instrumentation *instr,
                                     MemoryContext per_tuple_context);
static void AfterTriggerSaveEvent(EState *estate, ResultRelInfo *relinfo,
                                  ResultRelInfo *src_partinfo,
                                  ResultRelInfo *dst_partinfo,
                                  int event, bool row_trigger,
                                  TupleTableSlot *oldslot, TupleTableSlot *newslot,
                                  List *recheckIndexes, Bitmapset *modifiedCols,
                                  TransitionCaptureState *transition_capture,
                                  bool is_crosspart_update);
static void AfterTriggerEnlargeQueryState(void);
static bool before_stmt_triggers_fired(Oid relid, CmdType cmdType);
static HeapTuple check_modified_virtual_generated(TupleDesc tupdesc, HeapTuple tuple);
 
 
/*
 * Create a trigger.  Returns the address of the created trigger.
 *
 * queryString is the source text of the CREATE TRIGGER command.
 * This must be supplied if a whenClause is specified, else it can be NULL.
 *
 * relOid, if nonzero, is the relation on which the trigger should be
 * created.  If zero, the name provided in the statement will be looked up.
 *
 * refRelOid, if nonzero, is the relation to which the constraint trigger
 * refers.  If zero, the constraint relation name provided in the statement
 * will be looked up as needed.
 *
 * constraintOid, if nonzero, says that this trigger is being created
 * internally to implement that constraint.  A suitable pg_depend entry will
 * be made to link the trigger to that constraint.  constraintOid is zero when
 * executing a user-entered CREATE TRIGGER command.  (For CREATE CONSTRAINT
 * TRIGGER, we build a pg_constraint entry internally.)
 *
 * indexOid, if nonzero, is the OID of an index associated with the constraint.
 * We do nothing with this except store it into pg_trigger.tgconstrindid;
 * but when creating a trigger for a deferrable unique constraint on a
 * partitioned table, its children are looked up.  Note we don't cope with
 * invalid indexes in that case.
 *
 * funcoid, if nonzero, is the OID of the function to invoke.  When this is
 * given, stmt->funcname is ignored.
 *
 * parentTriggerOid, if nonzero, is a trigger that begets this one; so that
 * if that trigger is dropped, this one should be too.  There are two cases
 * when a nonzero value is passed for this: 1) when this function recurses to
 * create the trigger on partitions, 2) when creating child foreign key
 * triggers; see CreateFKCheckTrigger() and createForeignKeyActionTriggers().
 *
 * If whenClause is passed, it is an already-transformed expression for
 * WHEN.  In this case, we ignore any that may come in stmt->whenClause.
 *
 * If isInternal is true then this is an internally-generated trigger.
 * This argument sets the tgisinternal field of the pg_trigger entry, and
 * if true causes us to modify the given trigger name to ensure uniqueness.
 *
 * When isInternal is not true we require ACL_TRIGGER permissions on the
 * relation, as well as ACL_EXECUTE on the trigger function.  For internal
 * triggers the caller must apply any required permission checks.
 *
 * When called on partitioned tables, this function recurses to create the
 * trigger on all the partitions, except if isInternal is true, in which
 * case caller is expected to execute recursion on its own.  in_partition
 * indicates such a recursive call; outside callers should pass "false"
 * (but see CloneRowTriggersToPartition).
 */
ObjectAddress
CreateTrigger(const CreateTrigStmt *stmt, const char *queryString,
              Oid relOid, Oid refRelOid, Oid constraintOid, Oid indexOid,
              Oid funcoid, Oid parentTriggerOid, Node *whenClause,
              bool isInternal, bool in_partition)
{
    return
        CreateTriggerFiringOn(stmt, queryString, relOid, refRelOid,
                              constraintOid, indexOid, funcoid,
                              parentTriggerOid, whenClause, isInternal,
                              in_partition, TRIGGER_FIRES_ON_ORIGIN);
}
 
/*
 * Like the above; additionally the firing condition
 * (always/origin/replica/disabled) can be specified.
 */
ObjectAddress
CreateTriggerFiringOn(const CreateTrigStmt *stmt, const char *queryString,
                      Oid relOid, Oid refRelOid, Oid constraintOid,
                      Oid indexOid, Oid funcoid, Oid parentTriggerOid,
                      Node *whenClause, bool isInternal, bool in_partition,
                      char trigger_fires_when)
{
    int16       tgtype;
    int         ncolumns;
    int16      *columns;
    int2vector *tgattr;
    List       *whenRtable;
    char       *qual;
    Datum       values[Natts_pg_trigger];
    bool        nulls[Natts_pg_trigger];
    Relation    rel;
    AclResult   aclresult;
    Relation    tgrel;
    Relation    pgrel;
    HeapTuple   tuple = NULL;
    Oid         funcrettype;
    Oid         trigoid = InvalidOid;
    char        internaltrigname[NAMEDATALEN];
    char       *trigname;
    Oid         constrrelid = InvalidOid;
    ObjectAddress myself,
                referenced;
    char       *oldtablename = NULL;
    char       *newtablename = NULL;
    bool        partition_recurse;
    bool        trigger_exists = false;
    Oid         existing_constraint_oid = InvalidOid;
    bool        existing_isInternal = false;
    bool        existing_isClone = false;
 
    if (OidIsValid(relOid))
        rel = table_open(relOid, ShareRowExclusiveLock);
    else
        rel = table_openrv(stmt->relation, ShareRowExclusiveLock);
 
    /*
     * Triggers must be on tables or views, and there are additional
     * relation-type-specific restrictions.
     */
    if (rel->rd_rel->relkind == RELKIND_RELATION)
    {
        /* Tables can't have INSTEAD OF triggers */
        if (stmt->timing != TRIGGER_TYPE_BEFORE &&
            stmt->timing != TRIGGER_TYPE_AFTER)
            ereport(ERROR,
                    (errcode(ERRCODE_WRONG_OBJECT_TYPE),
                     errmsg("\"%s\" is a table",
                            RelationGetRelationName(rel)),
                     errdetail("Tables cannot have INSTEAD OF triggers.")));
    }
    else if (rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
    {
        /* Partitioned tables can't have INSTEAD OF triggers */
        if (stmt->timing != TRIGGER_TYPE_BEFORE &&
            stmt->timing != TRIGGER_TYPE_AFTER)
            ereport(ERROR,
                    (errcode(ERRCODE_WRONG_OBJECT_TYPE),
                     errmsg("\"%s\" is a table",
                            RelationGetRelationName(rel)),
                     errdetail("Tables cannot have INSTEAD OF triggers.")));
 
        /*
         * FOR EACH ROW triggers have further restrictions
         */
        if (stmt->row)
        {
            /*
             * Disallow use of transition tables.
             *
             * Note that we have another restriction about transition tables
             * in partitions; search for 'has_superclass' below for an
             * explanation.  The check here is just to protect from the fact
             * that if we allowed it here, the creation would succeed for a
             * partitioned table with no partitions, but would be blocked by
             * the other restriction when the first partition was created,
             * which is very unfriendly behavior.
             */
            if (stmt->transitionRels != NIL)
                ereport(ERROR,
                        (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
                         errmsg("\"%s\" is a partitioned table",
                                RelationGetRelationName(rel)),
                         errdetail("ROW triggers with transition tables are not supported on partitioned tables.")));
        }
    }
    else if (rel->rd_rel->relkind == RELKIND_VIEW)
    {
        /*
         * Views can have INSTEAD OF triggers (which we check below are
         * row-level), or statement-level BEFORE/AFTER triggers.
         */
        if (stmt->timing != TRIGGER_TYPE_INSTEAD && stmt->row)
            ereport(ERROR,
                    (errcode(ERRCODE_WRONG_OBJECT_TYPE),
                     errmsg("\"%s\" is a view",
                            RelationGetRelationName(rel)),
                     errdetail("Views cannot have row-level BEFORE or AFTER triggers.")));
        /* Disallow TRUNCATE triggers on VIEWs */
        if (TRIGGER_FOR_TRUNCATE(stmt->events))
            ereport(ERROR,
                    (errcode(ERRCODE_WRONG_OBJECT_TYPE),
                     errmsg("\"%s\" is a view",
                            RelationGetRelationName(rel)),
                     errdetail("Views cannot have TRUNCATE triggers.")));
    }
    else if (rel->rd_rel->relkind == RELKIND_FOREIGN_TABLE)
    {
        if (stmt->timing != TRIGGER_TYPE_BEFORE &&
            stmt->timing != TRIGGER_TYPE_AFTER)
            ereport(ERROR,
                    (errcode(ERRCODE_WRONG_OBJECT_TYPE),
                     errmsg("\"%s\" is a foreign table",
                            RelationGetRelationName(rel)),
                     errdetail("Foreign tables cannot have INSTEAD OF triggers.")));
 
        /*
         * We disallow constraint triggers to protect the assumption that
         * triggers on FKs can't be deferred.  See notes with AfterTriggers
         * data structures, below.
         */
        if (stmt->isconstraint)
            ereport(ERROR,
                    (errcode(ERRCODE_WRONG_OBJECT_TYPE),
                     errmsg("\"%s\" is a foreign table",
                            RelationGetRelationName(rel)),
                     errdetail("Foreign tables cannot have constraint triggers.")));
    }
    else
        ereport(ERROR,
                (errcode(ERRCODE_WRONG_OBJECT_TYPE),
                 errmsg("relation \"%s\" cannot have triggers",
                        RelationGetRelationName(rel)),
                 errdetail_relkind_not_supported(rel->rd_rel->relkind)));
 
    if (!allowSystemTableMods && IsSystemRelation(rel))
        ereport(ERROR,
                (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
                 errmsg("permission denied: \"%s\" is a system catalog",
                        RelationGetRelationName(rel))));
 
    if (stmt->isconstraint)
    {
        /*
         * We must take a lock on the target relation to protect against
         * concurrent drop.  It's not clear that AccessShareLock is strong
         * enough, but we certainly need at least that much... otherwise, we
         * might end up creating a pg_constraint entry referencing a
         * nonexistent table.
         */
        if (OidIsValid(refRelOid))
        {
            LockRelationOid(refRelOid, AccessShareLock);
            constrrelid = refRelOid;
        }
        else if (stmt->constrrel != NULL)
            constrrelid = RangeVarGetRelid(stmt->constrrel, AccessShareLock,
                                           false);
    }
 
    /* permission checks */
    if (!isInternal)
    {
        aclresult = pg_class_aclcheck(RelationGetRelid(rel), GetUserId(),
                                      ACL_TRIGGER);
        if (aclresult != ACLCHECK_OK)
            aclcheck_error(aclresult, get_relkind_objtype(rel->rd_rel->relkind),
                           RelationGetRelationName(rel));
 
        if (OidIsValid(constrrelid))
        {
            aclresult = pg_class_aclcheck(constrrelid, GetUserId(),
                                          ACL_TRIGGER);
            if (aclresult != ACLCHECK_OK)
                aclcheck_error(aclresult, get_relkind_objtype(get_rel_relkind(constrrelid)),
                               get_rel_name(constrrelid));
        }
    }
 
    /*
     * When called on a partitioned table to create a FOR EACH ROW trigger
     * that's not internal, we create one trigger for each partition, too.
     *
     * For that, we'd better hold lock on all of them ahead of time.
     */
    partition_recurse = !isInternal && stmt->row &&
        rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE;
    if (partition_recurse)
        list_free(find_all_inheritors(RelationGetRelid(rel),
                                      ShareRowExclusiveLock, NULL));
 
    /* Compute tgtype */
    TRIGGER_CLEAR_TYPE(tgtype);
    if (stmt->row)
        TRIGGER_SETT_ROW(tgtype);
    tgtype |= stmt->timing;
    tgtype |= stmt->events;
 
    /* Disallow ROW-level TRUNCATE triggers */
    if (TRIGGER_FOR_ROW(tgtype) && TRIGGER_FOR_TRUNCATE(tgtype))
        ereport(ERROR,
                (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
                 errmsg("TRUNCATE FOR EACH ROW triggers are not supported")));
 
    /* INSTEAD triggers must be row-level, and can't have WHEN or columns */
    if (TRIGGER_FOR_INSTEAD(tgtype))
    {
        if (!TRIGGER_FOR_ROW(tgtype))
            ereport(ERROR,
                    (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
                     errmsg("INSTEAD OF triggers must be FOR EACH ROW")));
        if (stmt->whenClause)
            ereport(ERROR,
                    (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
                     errmsg("INSTEAD OF triggers cannot have WHEN conditions")));
        if (stmt->columns != NIL)
            ereport(ERROR,
                    (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
                     errmsg("INSTEAD OF triggers cannot have column lists")));
    }
 
    /*
     * We don't yet support naming ROW transition variables, but the parser
     * recognizes the syntax so we can give a nicer message here.
     *
     * Per standard, REFERENCING TABLE names are only allowed on AFTER
     * triggers.  Per standard, REFERENCING ROW names are not allowed with FOR
     * EACH STATEMENT.  Per standard, each OLD/NEW, ROW/TABLE permutation is
     * only allowed once.  Per standard, OLD may not be specified when
     * creating a trigger only for INSERT, and NEW may not be specified when
     * creating a trigger only for DELETE.
     *
     * Notice that the standard allows an AFTER ... FOR EACH ROW trigger to
     * reference both ROW and TABLE transition data.
     */
    if (stmt->transitionRels != NIL)
    {
        List       *varList = stmt->transitionRels;
        ListCell   *lc;
 
        foreach(lc, varList)
        {
            TriggerTransition *tt = lfirst_node(TriggerTransition, lc);
 
            if (!(tt->isTable))
                ereport(ERROR,
                        (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
                         errmsg("ROW variable naming in the REFERENCING clause is not supported"),
                         errhint("Use OLD TABLE or NEW TABLE for naming transition tables.")));
 
            /*
             * Because of the above test, we omit further ROW-related testing
             * below.  If we later allow naming OLD and NEW ROW variables,
             * adjustments will be needed below.
             */
 
            if (rel->rd_rel->relkind == RELKIND_FOREIGN_TABLE)
                ereport(ERROR,
                        (errcode(ERRCODE_WRONG_OBJECT_TYPE),
                         errmsg("\"%s\" is a foreign table",
                                RelationGetRelationName(rel)),
                         errdetail("Triggers on foreign tables cannot have transition tables.")));
 
            if (rel->rd_rel->relkind == RELKIND_VIEW)
                ereport(ERROR,
                        (errcode(ERRCODE_WRONG_OBJECT_TYPE),
                         errmsg("\"%s\" is a view",
                                RelationGetRelationName(rel)),
                         errdetail("Triggers on views cannot have transition tables.")));
 
            /*
             * We currently don't allow row-level triggers with transition
             * tables on partition or inheritance children.  Such triggers
             * would somehow need to see tuples converted to the format of the
             * table they're attached to, and it's not clear which subset of
             * tuples each child should see.  See also the prohibitions in
             * ATExecAttachPartition() and ATExecAddInherit().
             */
            if (TRIGGER_FOR_ROW(tgtype) && has_superclass(rel->rd_id))
            {
                /* Use appropriate error message. */
                if (rel->rd_rel->relispartition)
                    ereport(ERROR,
                            (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
                             errmsg("ROW triggers with transition tables are not supported on partitions")));
                else
                    ereport(ERROR,
                            (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
                             errmsg("ROW triggers with transition tables are not supported on inheritance children")));
            }
 
            if (stmt->timing != TRIGGER_TYPE_AFTER)
                ereport(ERROR,
                        (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
                         errmsg("transition table name can only be specified for an AFTER trigger")));
 
            if (TRIGGER_FOR_TRUNCATE(tgtype))
                ereport(ERROR,
                        (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
                         errmsg("TRUNCATE triggers with transition tables are not supported")));
 
            /*
             * We currently don't allow multi-event triggers ("INSERT OR
             * UPDATE") with transition tables, because it's not clear how to
             * handle INSERT ... ON CONFLICT statements which can fire both
             * INSERT and UPDATE triggers.  We show the inserted tuples to
             * INSERT triggers and the updated tuples to UPDATE triggers, but
             * it's not yet clear what INSERT OR UPDATE trigger should see.
             * This restriction could be lifted if we can decide on the right
             * semantics in a later release.
             */
            if (((TRIGGER_FOR_INSERT(tgtype) ? 1 : 0) +
                 (TRIGGER_FOR_UPDATE(tgtype) ? 1 : 0) +
                 (TRIGGER_FOR_DELETE(tgtype) ? 1 : 0)) != 1)
                ereport(ERROR,
                        (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
                         errmsg("transition tables cannot be specified for triggers with more than one event")));
 
            /*
             * We currently don't allow column-specific triggers with
             * transition tables.  Per spec, that seems to require
             * accumulating separate transition tables for each combination of
             * columns, which is a lot of work for a rather marginal feature.
             */
            if (stmt->columns != NIL)
                ereport(ERROR,
                        (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
                         errmsg("transition tables cannot be specified for triggers with column lists")));
 
            /*
             * We disallow constraint triggers with transition tables, to
             * protect the assumption that such triggers can't be deferred.
             * See notes with AfterTriggers data structures, below.
             *
             * Currently this is enforced by the grammar, so just Assert here.
             */
            Assert(!stmt->isconstraint);
 
            if (tt->isNew)
            {
                if (!(TRIGGER_FOR_INSERT(tgtype) ||
                      TRIGGER_FOR_UPDATE(tgtype)))
                    ereport(ERROR,
                            (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
                             errmsg("NEW TABLE can only be specified for an INSERT or UPDATE trigger")));
 
                if (newtablename != NULL)
                    ereport(ERROR,
                            (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
                             errmsg("NEW TABLE cannot be specified multiple times")));
 
                newtablename = tt->name;
            }
            else
            {
                if (!(TRIGGER_FOR_DELETE(tgtype) ||
                      TRIGGER_FOR_UPDATE(tgtype)))
                    ereport(ERROR,
                            (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
                             errmsg("OLD TABLE can only be specified for a DELETE or UPDATE trigger")));
 
                if (oldtablename != NULL)
                    ereport(ERROR,
                            (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
                             errmsg("OLD TABLE cannot be specified multiple times")));
 
                oldtablename = tt->name;
            }
        }
 
        if (newtablename != NULL && oldtablename != NULL &&
            strcmp(newtablename, oldtablename) == 0)
            ereport(ERROR,
                    (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
                     errmsg("OLD TABLE name and NEW TABLE name cannot be the same")));
    }
 
    /*
     * Parse the WHEN clause, if any and we weren't passed an already
     * transformed one.
     *
     * Note that as a side effect, we fill whenRtable when parsing.  If we got
     * an already parsed clause, this does not occur, which is what we want --
     * no point in adding redundant dependencies below.
     */
    if (!whenClause && stmt->whenClause)
    {
        ParseState *pstate;
        ParseNamespaceItem *nsitem;
        List       *varList;
        ListCell   *lc;
 
        /* Set up a pstate to parse with */
        pstate = make_parsestate(NULL);
        pstate->p_sourcetext = queryString;
 
        /*
         * Set up nsitems for OLD and NEW references.
         *
         * 'OLD' must always have varno equal to 1 and 'NEW' equal to 2.
         */
        nsitem = addRangeTableEntryForRelation(pstate, rel,
                                               AccessShareLock,
                                               makeAlias("old", NIL),
                                               false, false);
        addNSItemToQuery(pstate, nsitem, false, true, true);
        nsitem = addRangeTableEntryForRelation(pstate, rel,
                                               AccessShareLock,
                                               makeAlias("new", NIL),
                                               false, false);
        addNSItemToQuery(pstate, nsitem, false, true, true);
 
        /* Transform expression.  Copy to be sure we don't modify original */
        whenClause = transformWhereClause(pstate,
                                          copyObject(stmt->whenClause),
                                          EXPR_KIND_TRIGGER_WHEN,
                                          "WHEN");
        /* we have to fix its collations too */
        assign_expr_collations(pstate, whenClause);
 
        /*
         * Check for disallowed references to OLD/NEW.
         *
         * NB: pull_var_clause is okay here only because we don't allow
         * subselects in WHEN clauses; it would fail to examine the contents
         * of subselects.
         */
        varList = pull_var_clause(whenClause, 0);
        foreach(lc, varList)
        {
            Var        *var = (Var *) lfirst(lc);
 
            switch (var->varno)
            {
                case PRS2_OLD_VARNO:
                    if (!TRIGGER_FOR_ROW(tgtype))
                        ereport(ERROR,
                                (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
                                 errmsg("statement trigger's WHEN condition cannot reference column values"),
                                 parser_errposition(pstate, var->location)));
                    if (TRIGGER_FOR_INSERT(tgtype))
                        ereport(ERROR,
                                (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
                                 errmsg("INSERT trigger's WHEN condition cannot reference OLD values"),
                                 parser_errposition(pstate, var->location)));
                    /* system columns are okay here */
                    break;
                case PRS2_NEW_VARNO:
                    if (!TRIGGER_FOR_ROW(tgtype))
                        ereport(ERROR,
                                (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
                                 errmsg("statement trigger's WHEN condition cannot reference column values"),
                                 parser_errposition(pstate, var->location)));
                    if (TRIGGER_FOR_DELETE(tgtype))
                        ereport(ERROR,
                                (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
                                 errmsg("DELETE trigger's WHEN condition cannot reference NEW values"),
                                 parser_errposition(pstate, var->location)));
                    if (var->varattno < 0 && TRIGGER_FOR_BEFORE(tgtype))
                        ereport(ERROR,
                                (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
                                 errmsg("BEFORE trigger's WHEN condition cannot reference NEW system columns"),
                                 parser_errposition(pstate, var->location)));
                    if (TRIGGER_FOR_BEFORE(tgtype) &&
                        var->varattno == 0 &&
                        RelationGetDescr(rel)->constr &&
                        (RelationGetDescr(rel)->constr->has_generated_stored ||
                         RelationGetDescr(rel)->constr->has_generated_virtual))
                        ereport(ERROR,
                                (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
                                 errmsg("BEFORE trigger's WHEN condition cannot reference NEW generated columns"),
                                 errdetail("A whole-row reference is used and the table contains generated columns."),
                                 parser_errposition(pstate, var->location)));
                    if (TRIGGER_FOR_BEFORE(tgtype) &&
                        var->varattno > 0 &&
                        TupleDescAttr(RelationGetDescr(rel), var->varattno - 1)->attgenerated)
                        ereport(ERROR,
                                (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
                                 errmsg("BEFORE trigger's WHEN condition cannot reference NEW generated columns"),
                                 errdetail("Column \"%s\" is a generated column.",
                                           NameStr(TupleDescAttr(RelationGetDescr(rel), var->varattno - 1)->attname)),
                                 parser_errposition(pstate, var->location)));
                    break;
                default:
                    /* can't happen without add_missing_from, so just elog */
                    elog(ERROR, "trigger WHEN condition cannot contain references to other relations");
                    break;
            }
        }
 
        /* we'll need the rtable for recordDependencyOnExpr */
        whenRtable = pstate->p_rtable;
 
        qual = nodeToString(whenClause);
 
        free_parsestate(pstate);
    }
    else if (!whenClause)
    {
        whenClause = NULL;
        whenRtable = NIL;
        qual = NULL;
    }
    else
    {
        qual = nodeToString(whenClause);
        whenRtable = NIL;
    }
 
    /*
     * Find and validate the trigger function.
     */
    if (!OidIsValid(funcoid))
        funcoid = LookupFuncName(stmt->funcname, 0, NULL, false);
    if (!isInternal)
    {
        aclresult = object_aclcheck(ProcedureRelationId, funcoid, GetUserId(), ACL_EXECUTE);
        if (aclresult != ACLCHECK_OK)
            aclcheck_error(aclresult, OBJECT_FUNCTION,
                           NameListToString(stmt->funcname));
    }
    funcrettype = get_func_rettype(funcoid);
    if (funcrettype != TRIGGEROID)
        ereport(ERROR,
                (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
                 errmsg("function %s must return type %s",
                        NameListToString(stmt->funcname), "trigger")));
 
    /*
     * Scan pg_trigger to see if there is already a trigger of the same name.
     * Skip this for internally generated triggers, since we'll modify the
     * name to be unique below.
     *
     * NOTE that this is cool only because we have ShareRowExclusiveLock on
     * the relation, so the trigger set won't be changing underneath us.
     */
    tgrel = table_open(TriggerRelationId, RowExclusiveLock);
    if (!isInternal)
    {
        ScanKeyData skeys[2];
        SysScanDesc tgscan;
 
        ScanKeyInit(&skeys[0],
                    Anum_pg_trigger_tgrelid,
                    BTEqualStrategyNumber, F_OIDEQ,
                    ObjectIdGetDatum(RelationGetRelid(rel)));
 
        ScanKeyInit(&skeys[1],
                    Anum_pg_trigger_tgname,
                    BTEqualStrategyNumber, F_NAMEEQ,
                    CStringGetDatum(stmt->trigname));
 
        tgscan = systable_beginscan(tgrel, TriggerRelidNameIndexId, true,
                                    NULL, 2, skeys);
 
        /* There should be at most one matching tuple */
        if (HeapTupleIsValid(tuple = systable_getnext(tgscan)))
        {
            Form_pg_trigger oldtrigger = (Form_pg_trigger) GETSTRUCT(tuple);
 
            trigoid = oldtrigger->oid;
            existing_constraint_oid = oldtrigger->tgconstraint;
            existing_isInternal = oldtrigger->tgisinternal;
            existing_isClone = OidIsValid(oldtrigger->tgparentid);
            trigger_exists = true;
            /* copy the tuple to use in CatalogTupleUpdate() */
            tuple = heap_copytuple(tuple);
        }
        systable_endscan(tgscan);
    }
 
    if (!trigger_exists)
    {
        /* Generate the OID for the new trigger. */
        trigoid = GetNewOidWithIndex(tgrel, TriggerOidIndexId,
                                     Anum_pg_trigger_oid);
    }
    else
    {
        /*
         * If OR REPLACE was specified, we'll replace the old trigger;
         * otherwise complain about the duplicate name.
         */
        if (!stmt->replace)
            ereport(ERROR,
                    (errcode(ERRCODE_DUPLICATE_OBJECT),
                     errmsg("trigger \"%s\" for relation \"%s\" already exists",
                            stmt->trigname, RelationGetRelationName(rel))));
 
        /*
         * An internal trigger or a child trigger (isClone) cannot be replaced
         * by a user-defined trigger.  However, skip this test when
         * in_partition, because then we're recursing from a partitioned table
         * and the check was made at the parent level.
         */
        if ((existing_isInternal || existing_isClone) &&
            !isInternal && !in_partition)
            ereport(ERROR,
                    (errcode(ERRCODE_DUPLICATE_OBJECT),
                     errmsg("trigger \"%s\" for relation \"%s\" is an internal or a child trigger",
                            stmt->trigname, RelationGetRelationName(rel))));
 
        /*
         * It is not allowed to replace with a constraint trigger; gram.y
         * should have enforced this already.
         */
        Assert(!stmt->isconstraint);
 
        /*
         * It is not allowed to replace an existing constraint trigger,
         * either.  (The reason for these restrictions is partly that it seems
         * difficult to deal with pending trigger events in such cases, and
         * partly that the command might imply changing the constraint's
         * properties as well, which doesn't seem nice.)
         */
        if (OidIsValid(existing_constraint_oid))
            ereport(ERROR,
                    (errcode(ERRCODE_DUPLICATE_OBJECT),
                     errmsg("trigger \"%s\" for relation \"%s\" is a constraint trigger",
                            stmt->trigname, RelationGetRelationName(rel))));
    }
 
    /*
     * If it's a user-entered CREATE CONSTRAINT TRIGGER command, make a
     * corresponding pg_constraint entry.
     */
    if (stmt->isconstraint && !OidIsValid(constraintOid))
    {
        /* Internal callers should have made their own constraints */
        Assert(!isInternal);
        constraintOid = CreateConstraintEntry(stmt->trigname,
                                              RelationGetNamespace(rel),
                                              CONSTRAINT_TRIGGER,
                                              stmt->deferrable,
                                              stmt->initdeferred,
                                              true, /* Is Enforced */
                                              true,
                                              InvalidOid,   /* no parent */
                                              RelationGetRelid(rel),
                                              NULL, /* no conkey */
                                              0,
                                              0,
                                              InvalidOid,   /* no domain */
                                              InvalidOid,   /* no index */
                                              InvalidOid,   /* no foreign key */
                                              NULL,
                                              NULL,
                                              NULL,
                                              NULL,
                                              0,
                                              ' ',
                                              ' ',
                                              NULL,
                                              0,
                                              ' ',
                                              NULL, /* no exclusion */
                                              NULL, /* no check constraint */
                                              NULL,
                                              true, /* islocal */
                                              0,    /* inhcount */
                                              true, /* noinherit */
                                              false,    /* conperiod */
                                              isInternal);  /* is_internal */
    }
 
    /*
     * If trigger is internally generated, modify the provided trigger name to
     * ensure uniqueness by appending the trigger OID.  (Callers will usually
     * supply a simple constant trigger name in these cases.)
     */
    if (isInternal)
    {
        snprintf(internaltrigname, sizeof(internaltrigname),
                 "%s_%u", stmt->trigname, trigoid);
        trigname = internaltrigname;
    }
    else
    {
        /* user-defined trigger; use the specified trigger name as-is */
        trigname = stmt->trigname;
    }
 
    /*
     * Build the new pg_trigger tuple.
     */
    memset(nulls, false, sizeof(nulls));
 
    values[Anum_pg_trigger_oid - 1] = ObjectIdGetDatum(trigoid);
    values[Anum_pg_trigger_tgrelid - 1] = ObjectIdGetDatum(RelationGetRelid(rel));
    values[Anum_pg_trigger_tgparentid - 1] = ObjectIdGetDatum(parentTriggerOid);
    values[Anum_pg_trigger_tgname - 1] = DirectFunctionCall1(namein,
                                                             CStringGetDatum(trigname));
    values[Anum_pg_trigger_tgfoid - 1] = ObjectIdGetDatum(funcoid);
    values[Anum_pg_trigger_tgtype - 1] = Int16GetDatum(tgtype);
    values[Anum_pg_trigger_tgenabled - 1] = CharGetDatum(trigger_fires_when);
    values[Anum_pg_trigger_tgisinternal - 1] = BoolGetDatum(isInternal);
    values[Anum_pg_trigger_tgconstrrelid - 1] = ObjectIdGetDatum(constrrelid);
    values[Anum_pg_trigger_tgconstrindid - 1] = ObjectIdGetDatum(indexOid);
    values[Anum_pg_trigger_tgconstraint - 1] = ObjectIdGetDatum(constraintOid);
    values[Anum_pg_trigger_tgdeferrable - 1] = BoolGetDatum(stmt->deferrable);
    values[Anum_pg_trigger_tginitdeferred - 1] = BoolGetDatum(stmt->initdeferred);
 
    if (stmt->args)
    {
        ListCell   *le;
        char       *args;
        int16       nargs = list_length(stmt->args);
        int         len = 0;
 
        foreach(le, stmt->args)
        {
            char       *ar = strVal(lfirst(le));
 
            len += strlen(ar) + 4;
            for (; *ar; ar++)
            {
                if (*ar == '\\')
                    len++;
            }
        }
        args = (char *) palloc(len + 1);
        args[0] = '\0';
        foreach(le, stmt->args)
        {
            char       *s = strVal(lfirst(le));
            char       *d = args + strlen(args);
 
            while (*s)
            {
                if (*s == '\\')
                    *d++ = '\\';
                *d++ = *s++;
            }
            strcpy(d, "\\000");
        }
        values[Anum_pg_trigger_tgnargs - 1] = Int16GetDatum(nargs);
        values[Anum_pg_trigger_tgargs - 1] = DirectFunctionCall1(byteain,
                                                                 CStringGetDatum(args));
    }
    else
    {
        values[Anum_pg_trigger_tgnargs - 1] = Int16GetDatum(0);
        values[Anum_pg_trigger_tgargs - 1] = DirectFunctionCall1(byteain,
                                                                 CStringGetDatum(""));
    }
 
    /* build column number array if it's a column-specific trigger */
    ncolumns = list_length(stmt->columns);
    if (ncolumns == 0)
        columns = NULL;
    else
    {
        ListCell   *cell;
        int         i = 0;
 
        columns = (int16 *) palloc(ncolumns * sizeof(int16));
        foreach(cell, stmt->columns)
        {
            char       *name = strVal(lfirst(cell));
            int16       attnum;
            int         j;
 
            /* Lookup column name.  System columns are not allowed */
            attnum = attnameAttNum(rel, name, false);
            if (attnum == InvalidAttrNumber)
                ereport(ERROR,
                        (errcode(ERRCODE_UNDEFINED_COLUMN),
                         errmsg("column \"%s\" of relation \"%s\" does not exist",
                                name, RelationGetRelationName(rel))));
 
            /* Check for duplicates */
            for (j = i - 1; j >= 0; j--)
            {
                if (columns[j] == attnum)
                    ereport(ERROR,
                            (errcode(ERRCODE_DUPLICATE_COLUMN),
                             errmsg("column \"%s\" specified more than once",
                                    name)));
            }
 
            columns[i++] = attnum;
        }
    }
    tgattr = buildint2vector(columns, ncolumns);
    values[Anum_pg_trigger_tgattr - 1] = PointerGetDatum(tgattr);
 
    /* set tgqual if trigger has WHEN clause */
    if (qual)
        values[Anum_pg_trigger_tgqual - 1] = CStringGetTextDatum(qual);
    else
        nulls[Anum_pg_trigger_tgqual - 1] = true;
 
    if (oldtablename)
        values[Anum_pg_trigger_tgoldtable - 1] = DirectFunctionCall1(namein,
                                                                     CStringGetDatum(oldtablename));
    else
        nulls[Anum_pg_trigger_tgoldtable - 1] = true;
    if (newtablename)
        values[Anum_pg_trigger_tgnewtable - 1] = DirectFunctionCall1(namein,
                                                                     CStringGetDatum(newtablename));
    else
        nulls[Anum_pg_trigger_tgnewtable - 1] = true;
 
    /*
     * Insert or replace tuple in pg_trigger.
     */
    if (!trigger_exists)
    {
        tuple = heap_form_tuple(tgrel->rd_att, values, nulls);
        CatalogTupleInsert(tgrel, tuple);
    }
    else
    {
        HeapTuple   newtup;
 
        newtup = heap_form_tuple(tgrel->rd_att, values, nulls);
        CatalogTupleUpdate(tgrel, &tuple->t_self, newtup);
        heap_freetuple(newtup);
    }
 
    heap_freetuple(tuple);      /* free either original or new tuple */
    table_close(tgrel, RowExclusiveLock);
 
    pfree(DatumGetPointer(values[Anum_pg_trigger_tgname - 1]));
    pfree(DatumGetPointer(values[Anum_pg_trigger_tgargs - 1]));
    pfree(DatumGetPointer(values[Anum_pg_trigger_tgattr - 1]));
    if (oldtablename)
        pfree(DatumGetPointer(values[Anum_pg_trigger_tgoldtable - 1]));
    if (newtablename)
        pfree(DatumGetPointer(values[Anum_pg_trigger_tgnewtable - 1]));
 
    /*
     * Update relation's pg_class entry; if necessary; and if not, send an SI
     * message to make other backends (and this one) rebuild relcache entries.
     */
    pgrel = table_open(RelationRelationId, RowExclusiveLock);
    tuple = SearchSysCacheCopy1(RELOID,
                                ObjectIdGetDatum(RelationGetRelid(rel)));
    if (!HeapTupleIsValid(tuple))
        elog(ERROR, "cache lookup failed for relation %u",
             RelationGetRelid(rel));
    if (!((Form_pg_class) GETSTRUCT(tuple))->relhastriggers)
    {
        ((Form_pg_class) GETSTRUCT(tuple))->relhastriggers = true;
 
        CatalogTupleUpdate(pgrel, &tuple->t_self, tuple);
 
        CommandCounterIncrement();
    }
    else
        CacheInvalidateRelcacheByTuple(tuple);
 
    heap_freetuple(tuple);
    table_close(pgrel, RowExclusiveLock);
 
    /*
     * If we're replacing a trigger, flush all the old dependencies before
     * recording new ones.
     */
    if (trigger_exists)
        deleteDependencyRecordsFor(TriggerRelationId, trigoid, true);
 
    /*
     * Record dependencies for trigger.  Always place a normal dependency on
     * the function.
     */
    myself.classId = TriggerRelationId;
    myself.objectId = trigoid;
    myself.objectSubId = 0;
 
    referenced.classId = ProcedureRelationId;
    referenced.objectId = funcoid;
    referenced.objectSubId = 0;
    recordDependencyOn(&myself, &referenced, DEPENDENCY_NORMAL);
 
    if (isInternal && OidIsValid(constraintOid))
    {
        /*
         * Internally-generated trigger for a constraint, so make it an
         * internal dependency of the constraint.  We can skip depending on
         * the relation(s), as there'll be an indirect dependency via the
         * constraint.
         */
        referenced.classId = ConstraintRelationId;
        referenced.objectId = constraintOid;
        referenced.objectSubId = 0;
        recordDependencyOn(&myself, &referenced, DEPENDENCY_INTERNAL);
    }
    else
    {
        /*
         * User CREATE TRIGGER, so place dependencies.  We make trigger be
         * auto-dropped if its relation is dropped or if the FK relation is
         * dropped.  (Auto drop is compatible with our pre-7.3 behavior.)
         */
        referenced.classId = RelationRelationId;
        referenced.objectId = RelationGetRelid(rel);
        referenced.objectSubId = 0;
        recordDependencyOn(&myself, &referenced, DEPENDENCY_AUTO);
 
        if (OidIsValid(constrrelid))
        {
            referenced.classId = RelationRelationId;
            referenced.objectId = constrrelid;
            referenced.objectSubId = 0;
            recordDependencyOn(&myself, &referenced, DEPENDENCY_AUTO);
        }
        /* Not possible to have an index dependency in this case */
        Assert(!OidIsValid(indexOid));
 
        /*
         * If it's a user-specified constraint trigger, make the constraint
         * internally dependent on the trigger instead of vice versa.
         */
        if (OidIsValid(constraintOid))
        {
            referenced.classId = ConstraintRelationId;
            referenced.objectId = constraintOid;
            referenced.objectSubId = 0;
            recordDependencyOn(&referenced, &myself, DEPENDENCY_INTERNAL);
        }
 
        /*
         * If it's a partition trigger, create the partition dependencies.
         */
        if (OidIsValid(parentTriggerOid))
        {
            ObjectAddressSet(referenced, TriggerRelationId, parentTriggerOid);
            recordDependencyOn(&myself, &referenced, DEPENDENCY_PARTITION_PRI);
            ObjectAddressSet(referenced, RelationRelationId, RelationGetRelid(rel));
            recordDependencyOn(&myself, &referenced, DEPENDENCY_PARTITION_SEC);
        }
    }
 
    /* If column-specific trigger, add normal dependencies on columns */
    if (columns != NULL)
    {
        int         i;
 
        referenced.classId = RelationRelationId;
        referenced.objectId = RelationGetRelid(rel);
        for (i = 0; i < ncolumns; i++)
        {
            referenced.objectSubId = columns[i];
            recordDependencyOn(&myself, &referenced, DEPENDENCY_NORMAL);
        }
    }
 
    /*
     * If it has a WHEN clause, add dependencies on objects mentioned in the
     * expression (eg, functions, as well as any columns used).
     */
    if (whenRtable != NIL)
        recordDependencyOnExpr(&myself, whenClause, whenRtable,
                               DEPENDENCY_NORMAL);
 
    /* Post creation hook for new trigger */
    InvokeObjectPostCreateHookArg(TriggerRelationId, trigoid, 0,
                                  isInternal);
 
    /*
     * Lastly, create the trigger on child relations, if needed.
     */
    if (partition_recurse)
    {
        PartitionDesc partdesc = RelationGetPartitionDesc(rel, true);
        int         i;
        MemoryContext oldcxt,
                    perChildCxt;
 
        perChildCxt = AllocSetContextCreate(CurrentMemoryContext,
                                            "part trig clone",
                                            ALLOCSET_SMALL_SIZES);
 
        /*
         * We don't currently expect to be called with a valid indexOid.  If
         * that ever changes then we'll need to write code here to find the
         * corresponding child index.
         */
        Assert(!OidIsValid(indexOid));
 
        oldcxt = MemoryContextSwitchTo(perChildCxt);
 
        /* Iterate to create the trigger on each existing partition */
        for (i = 0; i < partdesc->nparts; i++)
        {
            CreateTrigStmt *childStmt;
            Relation    childTbl;
            Node       *qual;
 
            childTbl = table_open(partdesc->oids[i], ShareRowExclusiveLock);
 
            /*
             * Initialize our fabricated parse node by copying the original
             * one, then resetting fields that we pass separately.
             */
            childStmt = copyObject(stmt);
            childStmt->funcname = NIL;
            childStmt->whenClause = NULL;
 
            /* If there is a WHEN clause, create a modified copy of it */
            qual = copyObject(whenClause);
            qual = (Node *)
                map_partition_varattnos((List *) qual, PRS2_OLD_VARNO,
                                        childTbl, rel);
            qual = (Node *)
                map_partition_varattnos((List *) qual, PRS2_NEW_VARNO,
                                        childTbl, rel);
 
            CreateTriggerFiringOn(childStmt, queryString,
                                  partdesc->oids[i], refRelOid,
                                  InvalidOid, InvalidOid,
                                  funcoid, trigoid, qual,
                                  isInternal, true, trigger_fires_when);
 
            table_close(childTbl, NoLock);
 
            MemoryContextReset(perChildCxt);
        }
 
        MemoryContextSwitchTo(oldcxt);
        MemoryContextDelete(perChildCxt);
    }
 
    /* Keep lock on target rel until end of xact */
    table_close(rel, NoLock);
 
    return myself;
}
 
/*
 * TriggerSetParentTrigger
 *      Set a partition's trigger as child of its parent trigger,
 *      or remove the linkage if parentTrigId is InvalidOid.
 *
 * This updates the constraint's pg_trigger row to show it as inherited, and
 * adds PARTITION dependencies to prevent the trigger from being deleted
 * on its own.  Alternatively, reverse that.
 */
void
TriggerSetParentTrigger(Relation trigRel,
                        Oid childTrigId,
                        Oid parentTrigId,
                        Oid childTableId)
{
    SysScanDesc tgscan;
    ScanKeyData skey[1];
    Form_pg_trigger trigForm;
    HeapTuple   tuple,
                newtup;
    ObjectAddress depender;
    ObjectAddress referenced;
 
    /*
     * Find the trigger to delete.
     */
    ScanKeyInit(&skey[0],
                Anum_pg_trigger_oid,
                BTEqualStrategyNumber, F_OIDEQ,
                ObjectIdGetDatum(childTrigId));
 
    tgscan = systable_beginscan(trigRel, TriggerOidIndexId, true,
                                NULL, 1, skey);
 
    tuple = systable_getnext(tgscan);
    if (!HeapTupleIsValid(tuple))
        elog(ERROR, "could not find tuple for trigger %u", childTrigId);
    newtup = heap_copytuple(tuple);
    trigForm = (Form_pg_trigger) GETSTRUCT(newtup);
    if (OidIsValid(parentTrigId))
    {
        /* don't allow setting parent for a constraint that already has one */
        if (OidIsValid(trigForm->tgparentid))
            elog(ERROR, "trigger %u already has a parent trigger",
                 childTrigId);
 
        trigForm->tgparentid = parentTrigId;
 
        CatalogTupleUpdate(trigRel, &tuple->t_self, newtup);
 
        ObjectAddressSet(depender, TriggerRelationId, childTrigId);
 
        ObjectAddressSet(referenced, TriggerRelationId, parentTrigId);
        recordDependencyOn(&depender, &referenced, DEPENDENCY_PARTITION_PRI);
 
        ObjectAddressSet(referenced, RelationRelationId, childTableId);
        recordDependencyOn(&depender, &referenced, DEPENDENCY_PARTITION_SEC);
    }
    else
    {
        trigForm->tgparentid = InvalidOid;
 
        CatalogTupleUpdate(trigRel, &tuple->t_self, newtup);
 
        deleteDependencyRecordsForClass(TriggerRelationId, childTrigId,
                                        TriggerRelationId,
                                        DEPENDENCY_PARTITION_PRI);
        deleteDependencyRecordsForClass(TriggerRelationId, childTrigId,
                                        RelationRelationId,
                                        DEPENDENCY_PARTITION_SEC);
    }
 
    heap_freetuple(newtup);
    systable_endscan(tgscan);
}
 
 
/*
 * Guts of trigger deletion.
 */
void
RemoveTriggerById(Oid trigOid)
{
    Relation    tgrel;
    SysScanDesc tgscan;
    ScanKeyData skey[1];
    HeapTuple   tup;
    Oid         relid;
    Relation    rel;
 
    tgrel = table_open(TriggerRelationId, RowExclusiveLock);
 
    /*
     * Find the trigger to delete.
     */
    ScanKeyInit(&skey[0],
                Anum_pg_trigger_oid,
                BTEqualStrategyNumber, F_OIDEQ,
                ObjectIdGetDatum(trigOid));
 
    tgscan = systable_beginscan(tgrel, TriggerOidIndexId, true,
                                NULL, 1, skey);
 
    tup = systable_getnext(tgscan);
    if (!HeapTupleIsValid(tup))
        elog(ERROR, "could not find tuple for trigger %u", trigOid);
 
    /*
     * Open and exclusive-lock the relation the trigger belongs to.
     */
    relid = ((Form_pg_trigger) GETSTRUCT(tup))->tgrelid;
 
    rel = table_open(relid, AccessExclusiveLock);
 
    if (rel->rd_rel->relkind != RELKIND_RELATION &&
        rel->rd_rel->relkind != RELKIND_VIEW &&
        rel->rd_rel->relkind != RELKIND_FOREIGN_TABLE &&
        rel->rd_rel->relkind != RELKIND_PARTITIONED_TABLE)
        ereport(ERROR,
                (errcode(ERRCODE_WRONG_OBJECT_TYPE),
                 errmsg("relation \"%s\" cannot have triggers",
                        RelationGetRelationName(rel)),
                 errdetail_relkind_not_supported(rel->rd_rel->relkind)));
 
    if (!allowSystemTableMods && IsSystemRelation(rel))
        ereport(ERROR,
                (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
                 errmsg("permission denied: \"%s\" is a system catalog",
                        RelationGetRelationName(rel))));
 
    /*
     * Delete the pg_trigger tuple.
     */
    CatalogTupleDelete(tgrel, &tup->t_self);
 
    systable_endscan(tgscan);
    table_close(tgrel, RowExclusiveLock);
 
    /*
     * We do not bother to try to determine whether any other triggers remain,
     * which would be needed in order to decide whether it's safe to clear the
     * relation's relhastriggers.  (In any case, there might be a concurrent
     * process adding new triggers.)  Instead, just force a relcache inval to
     * make other backends (and this one too!) rebuild their relcache entries.
     * There's no great harm in leaving relhastriggers true even if there are
     * no triggers left.
     */
    CacheInvalidateRelcache(rel);
 
    /* Keep lock on trigger's rel until end of xact */
    table_close(rel, NoLock);
}
 
/*
 * get_trigger_oid - Look up a trigger by name to find its OID.
 *
 * If missing_ok is false, throw an error if trigger not found.  If
 * true, just return InvalidOid.
 */
Oid
get_trigger_oid(Oid relid, const char *trigname, bool missing_ok)
{
    Relation    tgrel;
    ScanKeyData skey[2];
    SysScanDesc tgscan;
    HeapTuple   tup;
    Oid         oid;
 
    /*
     * Find the trigger, verify permissions, set up object address
     */
    tgrel = table_open(TriggerRelationId, AccessShareLock);
 
    ScanKeyInit(&skey[0],
                Anum_pg_trigger_tgrelid,
                BTEqualStrategyNumber, F_OIDEQ,
                ObjectIdGetDatum(relid));
    ScanKeyInit(&skey[1],
                Anum_pg_trigger_tgname,
                BTEqualStrategyNumber, F_NAMEEQ,
                CStringGetDatum(trigname));
 
    tgscan = systable_beginscan(tgrel, TriggerRelidNameIndexId, true,
                                NULL, 2, skey);
 
    tup = systable_getnext(tgscan);
 
    if (!HeapTupleIsValid(tup))
    {
        if (!missing_ok)
            ereport(ERROR,
                    (errcode(ERRCODE_UNDEFINED_OBJECT),
                     errmsg("trigger \"%s\" for table \"%s\" does not exist",
                            trigname, get_rel_name(relid))));
        oid = InvalidOid;
    }
    else
    {
        oid = ((Form_pg_trigger) GETSTRUCT(tup))->oid;
    }
 
    systable_endscan(tgscan);
    table_close(tgrel, AccessShareLock);
    return oid;
}
 
/*
 * Perform permissions and integrity checks before acquiring a relation lock.
 */
static void
RangeVarCallbackForRenameTrigger(const RangeVar *rv, Oid relid, Oid oldrelid,
                                 void *arg)
{
    HeapTuple   tuple;
    Form_pg_class form;
 
    tuple = SearchSysCache1(RELOID, ObjectIdGetDatum(relid));
    if (!HeapTupleIsValid(tuple))
        return;                 /* concurrently dropped */
    form = (Form_pg_class) GETSTRUCT(tuple);
 
    /* only tables and views can have triggers */
    if (form->relkind != RELKIND_RELATION && form->relkind != RELKIND_VIEW &&
        form->relkind != RELKIND_FOREIGN_TABLE &&
        form->relkind != RELKIND_PARTITIONED_TABLE)
        ereport(ERROR,
                (errcode(ERRCODE_WRONG_OBJECT_TYPE),
                 errmsg("relation \"%s\" cannot have triggers",
                        rv->relname),
                 errdetail_relkind_not_supported(form->relkind)));
 
    /* you must own the table to rename one of its triggers */
    if (!object_ownercheck(RelationRelationId, relid, GetUserId()))
        aclcheck_error(ACLCHECK_NOT_OWNER, get_relkind_objtype(get_rel_relkind(relid)), rv->relname);
    if (!allowSystemTableMods && IsSystemClass(relid, form))
        ereport(ERROR,
                (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
                 errmsg("permission denied: \"%s\" is a system catalog",
                        rv->relname)));
 
    ReleaseSysCache(tuple);
}
 
/*
 *      renametrig      - changes the name of a trigger on a relation
 *
 *      trigger name is changed in trigger catalog.
 *      No record of the previous name is kept.
 *
 *      get proper relrelation from relation catalog (if not arg)
 *      scan trigger catalog
 *              for name conflict (within rel)
 *              for original trigger (if not arg)
 *      modify tgname in trigger tuple
 *      update row in catalog
 */
ObjectAddress
renametrig(RenameStmt *stmt)
{
    Oid         tgoid;
    Relation    targetrel;
    Relation    tgrel;
    HeapTuple   tuple;
    SysScanDesc tgscan;
    ScanKeyData key[2];
    Oid         relid;
    ObjectAddress address;
 
    /*
     * Look up name, check permissions, and acquire lock (which we will NOT
     * release until end of transaction).
     */
    relid = RangeVarGetRelidExtended(stmt->relation, AccessExclusiveLock,
                                     0,
                                     RangeVarCallbackForRenameTrigger,
                                     NULL);
 
    /* Have lock already, so just need to build relcache entry. */
    targetrel = relation_open(relid, NoLock);
 
    /*
     * On partitioned tables, this operation recurses to partitions.  Lock all
     * tables upfront.
     */
    if (targetrel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
        (void) find_all_inheritors(relid, AccessExclusiveLock, NULL);
 
    tgrel = table_open(TriggerRelationId, RowExclusiveLock);
 
    /*
     * Search for the trigger to modify.
     */
    ScanKeyInit(&key[0],
                Anum_pg_trigger_tgrelid,
                BTEqualStrategyNumber, F_OIDEQ,
                ObjectIdGetDatum(relid));
    ScanKeyInit(&key[1],
                Anum_pg_trigger_tgname,
                BTEqualStrategyNumber, F_NAMEEQ,
                PointerGetDatum(stmt->subname));
    tgscan = systable_beginscan(tgrel, TriggerRelidNameIndexId, true,
                                NULL, 2, key);
    if (HeapTupleIsValid(tuple = systable_getnext(tgscan)))
    {
        Form_pg_trigger trigform;
 
        trigform = (Form_pg_trigger) GETSTRUCT(tuple);
        tgoid = trigform->oid;
 
        /*
         * If the trigger descends from a trigger on a parent partitioned
         * table, reject the rename.  We don't allow a trigger in a partition
         * to differ in name from that of its parent: that would lead to an
         * inconsistency that pg_dump would not reproduce.
         */
        if (OidIsValid(trigform->tgparentid))
            ereport(ERROR,
                    errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
                    errmsg("cannot rename trigger \"%s\" on table \"%s\"",
                           stmt->subname, RelationGetRelationName(targetrel)),
                    errhint("Rename the trigger on the partitioned table \"%s\" instead.",
                            get_rel_name(get_partition_parent(relid, false))));
 
 
        /* Rename the trigger on this relation ... */
        renametrig_internal(tgrel, targetrel, tuple, stmt->newname,
                            stmt->subname);
 
        /* ... and if it is partitioned, recurse to its partitions */
        if (targetrel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
        {
            PartitionDesc partdesc = RelationGetPartitionDesc(targetrel, true);
 
            for (int i = 0; i < partdesc->nparts; i++)
            {
                Oid         partitionId = partdesc->oids[i];
 
                renametrig_partition(tgrel, partitionId, trigform->oid,
                                     stmt->newname, stmt->subname);
            }
        }
    }
    else
    {
        ereport(ERROR,
                (errcode(ERRCODE_UNDEFINED_OBJECT),
                 errmsg("trigger \"%s\" for table \"%s\" does not exist",
                        stmt->subname, RelationGetRelationName(targetrel))));
    }
 
    ObjectAddressSet(address, TriggerRelationId, tgoid);
 
    systable_endscan(tgscan);
 
    table_close(tgrel, RowExclusiveLock);
 
    /*
     * Close rel, but keep exclusive lock!
     */
    relation_close(targetrel, NoLock);
 
    return address;
}
 
/*
 * Subroutine for renametrig -- perform the actual work of renaming one
 * trigger on one table.
 *
 * If the trigger has a name different from the expected one, raise a
 * NOTICE about it.
 */
static void
renametrig_internal(Relation tgrel, Relation targetrel, HeapTuple trigtup,
                    const char *newname, const char *expected_name)
{
    HeapTuple   tuple;
    Form_pg_trigger tgform;
    ScanKeyData key[2];
    SysScanDesc tgscan;
 
    /* If the trigger already has the new name, nothing to do. */
    tgform = (Form_pg_trigger) GETSTRUCT(trigtup);
    if (strcmp(NameStr(tgform->tgname), newname) == 0)
        return;
 
    /*
     * Before actually trying the rename, search for triggers with the same
     * name.  The update would fail with an ugly message in that case, and it
     * is better to throw a nicer error.
     */
    ScanKeyInit(&key[0],
                Anum_pg_trigger_tgrelid,
                BTEqualStrategyNumber, F_OIDEQ,
                ObjectIdGetDatum(RelationGetRelid(targetrel)));
    ScanKeyInit(&key[1],
                Anum_pg_trigger_tgname,
                BTEqualStrategyNumber, F_NAMEEQ,
                PointerGetDatum(newname));
    tgscan = systable_beginscan(tgrel, TriggerRelidNameIndexId, true,
                                NULL, 2, key);
    if (HeapTupleIsValid(tuple = systable_getnext(tgscan)))
        ereport(ERROR,
                (errcode(ERRCODE_DUPLICATE_OBJECT),
                 errmsg("trigger \"%s\" for relation \"%s\" already exists",
                        newname, RelationGetRelationName(targetrel))));
    systable_endscan(tgscan);
 
    /*
     * The target name is free; update the existing pg_trigger tuple with it.
     */
    tuple = heap_copytuple(trigtup);    /* need a modifiable copy */
    tgform = (Form_pg_trigger) GETSTRUCT(tuple);
 
    /*
     * If the trigger has a name different from what we expected, let the user
     * know. (We can proceed anyway, since we must have reached here following
     * a tgparentid link.)
     */
    if (strcmp(NameStr(tgform->tgname), expected_name) != 0)
        ereport(NOTICE,
                errmsg("renamed trigger \"%s\" on relation \"%s\"",
                       NameStr(tgform->tgname),
                       RelationGetRelationName(targetrel)));
 
    namestrcpy(&tgform->tgname, newname);
 
    CatalogTupleUpdate(tgrel, &tuple->t_self, tuple);
 
    InvokeObjectPostAlterHook(TriggerRelationId, tgform->oid, 0);
 
    /*
     * Invalidate relation's relcache entry so that other backends (and this
     * one too!) are sent SI message to make them rebuild relcache entries.
     * (Ideally this should happen automatically...)
     */
    CacheInvalidateRelcache(targetrel);
}
 
/*
 * Subroutine for renametrig -- Helper for recursing to partitions when
 * renaming triggers on a partitioned table.
 */
static void
renametrig_partition(Relation tgrel, Oid partitionId, Oid parentTriggerOid,
                     const char *newname, const char *expected_name)
{
    SysScanDesc tgscan;
    ScanKeyData key;
    HeapTuple   tuple;
 
    /*
     * Given a relation and the OID of a trigger on parent relation, find the
     * corresponding trigger in the child and rename that trigger to the given
     * name.
     */
    ScanKeyInit(&key,
                Anum_pg_trigger_tgrelid,
                BTEqualStrategyNumber, F_OIDEQ,
                ObjectIdGetDatum(partitionId));
    tgscan = systable_beginscan(tgrel, TriggerRelidNameIndexId, true,
                                NULL, 1, &key);
    while (HeapTupleIsValid(tuple = systable_getnext(tgscan)))
    {
        Form_pg_trigger tgform = (Form_pg_trigger) GETSTRUCT(tuple);
        Relation    partitionRel;
 
        if (tgform->tgparentid != parentTriggerOid)
            continue;           /* not our trigger */
 
        partitionRel = table_open(partitionId, NoLock);
 
        /* Rename the trigger on this partition */
        renametrig_internal(tgrel, partitionRel, tuple, newname, expected_name);
 
        /* And if this relation is partitioned, recurse to its partitions */
        if (partitionRel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
        {
            PartitionDesc partdesc = RelationGetPartitionDesc(partitionRel,
                                                              true);
 
            for (int i = 0; i < partdesc->nparts; i++)
            {
                Oid         partoid = partdesc->oids[i];
 
                renametrig_partition(tgrel, partoid, tgform->oid, newname,
                                     NameStr(tgform->tgname));
            }
        }
        table_close(partitionRel, NoLock);
 
        /* There should be at most one matching tuple */
        break;
    }
    systable_endscan(tgscan);
}
 
/*
 * EnableDisableTrigger()
 *
 *  Called by ALTER TABLE ENABLE/DISABLE [ REPLICA | ALWAYS ] TRIGGER
 *  to change 'tgenabled' field for the specified trigger(s)
 *
 * rel: relation to process (caller must hold suitable lock on it)
 * tgname: name of trigger to process, or NULL to scan all triggers
 * tgparent: if not zero, process only triggers with this tgparentid
 * fires_when: new value for tgenabled field. In addition to generic
 *             enablement/disablement, this also defines when the trigger
 *             should be fired in session replication roles.
 * skip_system: if true, skip "system" triggers (constraint triggers)
 * recurse: if true, recurse to partitions
 *
 * Caller should have checked permissions for the table; here we also
 * enforce that superuser privilege is required to alter the state of
 * system triggers
 */
void
EnableDisableTrigger(Relation rel, const char *tgname, Oid tgparent,
                     char fires_when, bool skip_system, bool recurse,
                     LOCKMODE lockmode)
{
    Relation    tgrel;
    int         nkeys;
    ScanKeyData keys[2];
    SysScanDesc tgscan;
    HeapTuple   tuple;
    bool        found;
    bool        changed;
 
    /* Scan the relevant entries in pg_triggers */
    tgrel = table_open(TriggerRelationId, RowExclusiveLock);
 
    ScanKeyInit(&keys[0],
                Anum_pg_trigger_tgrelid,
                BTEqualStrategyNumber, F_OIDEQ,
                ObjectIdGetDatum(RelationGetRelid(rel)));
    if (tgname)
    {
        ScanKeyInit(&keys[1],
                    Anum_pg_trigger_tgname,
                    BTEqualStrategyNumber, F_NAMEEQ,
                    CStringGetDatum(tgname));
        nkeys = 2;
    }
    else
        nkeys = 1;
 
    tgscan = systable_beginscan(tgrel, TriggerRelidNameIndexId, true,
                                NULL, nkeys, keys);
 
    found = changed = false;
 
    while (HeapTupleIsValid(tuple = systable_getnext(tgscan)))
    {
        Form_pg_trigger oldtrig = (Form_pg_trigger) GETSTRUCT(tuple);
 
        if (OidIsValid(tgparent) && tgparent != oldtrig->tgparentid)
            continue;
 
        if (oldtrig->tgisinternal)
        {
            /* system trigger ... ok to process? */
            if (skip_system)
                continue;
            if (!superuser())
                ereport(ERROR,
                        (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
                         errmsg("permission denied: \"%s\" is a system trigger",
                                NameStr(oldtrig->tgname))));
        }
 
        found = true;
 
        if (oldtrig->tgenabled != fires_when)
        {
            /* need to change this one ... make a copy to scribble on */
            HeapTuple   newtup = heap_copytuple(tuple);
            Form_pg_trigger newtrig = (Form_pg_trigger) GETSTRUCT(newtup);
 
            newtrig->tgenabled = fires_when;
 
            CatalogTupleUpdate(tgrel, &newtup->t_self, newtup);
 
            heap_freetuple(newtup);
 
            changed = true;
        }
 
        /*
         * When altering FOR EACH ROW triggers on a partitioned table, do the
         * same on the partitions as well, unless ONLY is specified.
         *
         * Note that we recurse even if we didn't change the trigger above,
         * because the partitions' copy of the trigger may have a different
         * value of tgenabled than the parent's trigger and thus might need to
         * be changed.
         */
        if (recurse &&
            rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE &&
            (TRIGGER_FOR_ROW(oldtrig->tgtype)))
        {
            PartitionDesc partdesc = RelationGetPartitionDesc(rel, true);
            int         i;
 
            for (i = 0; i < partdesc->nparts; i++)
            {
                Relation    part;
 
                part = relation_open(partdesc->oids[i], lockmode);
                /* Match on child triggers' tgparentid, not their name */
                EnableDisableTrigger(part, NULL, oldtrig->oid,
                                     fires_when, skip_system, recurse,
                                     lockmode);
                table_close(part, NoLock);  /* keep lock till commit */
            }
        }
 
        InvokeObjectPostAlterHook(TriggerRelationId,
                                  oldtrig->oid, 0);
    }
 
    systable_endscan(tgscan);
 
    table_close(tgrel, RowExclusiveLock);
 
    if (tgname && !found)
        ereport(ERROR,
                (errcode(ERRCODE_UNDEFINED_OBJECT),
                 errmsg("trigger \"%s\" for table \"%s\" does not exist",
                        tgname, RelationGetRelationName(rel))));
 
    /*
     * If we changed anything, broadcast a SI inval message to force each
     * backend (including our own!) to rebuild relation's relcache entry.
     * Otherwise they will fail to apply the change promptly.
     */
    if (changed)
        CacheInvalidateRelcache(rel);
}
 
 
/*
 * Build trigger data to attach to the given relcache entry.
 *
 * Note that trigger data attached to a relcache entry must be stored in
 * CacheMemoryContext to ensure it survives as long as the relcache entry.
 * But we should be running in a less long-lived working context.  To avoid
 * leaking cache memory if this routine fails partway through, we build a
 * temporary TriggerDesc in working memory and then copy the completed
 * structure into cache memory.
 */
void
RelationBuildTriggers(Relation relation)
{
    TriggerDesc *trigdesc;
    int         numtrigs;
    int         maxtrigs;
    Trigger    *triggers;
    Relation    tgrel;
    ScanKeyData skey;
    SysScanDesc tgscan;
    HeapTuple   htup;
    MemoryContext oldContext;
    int         i;
 
    /*
     * Allocate a working array to hold the triggers (the array is extended if
     * necessary)
     */
    maxtrigs = 16;
    triggers = (Trigger *) palloc(maxtrigs * sizeof(Trigger));
    numtrigs = 0;
 
    /*
     * Note: since we scan the triggers using TriggerRelidNameIndexId, we will
     * be reading the triggers in name order, except possibly during
     * emergency-recovery operations (ie, IgnoreSystemIndexes). This in turn
     * ensures that triggers will be fired in name order.
     */
    ScanKeyInit(&skey,
                Anum_pg_trigger_tgrelid,
                BTEqualStrategyNumber, F_OIDEQ,
                ObjectIdGetDatum(RelationGetRelid(relation)));
 
    tgrel = table_open(TriggerRelationId, AccessShareLock);
    tgscan = systable_beginscan(tgrel, TriggerRelidNameIndexId, true,
                                NULL, 1, &skey);
 
    while (HeapTupleIsValid(htup = systable_getnext(tgscan)))
    {
        Form_pg_trigger pg_trigger = (Form_pg_trigger) GETSTRUCT(htup);
        Trigger    *build;
        Datum       datum;
        bool        isnull;
 
        if (numtrigs >= maxtrigs)
        {
            maxtrigs *= 2;
            triggers = (Trigger *) repalloc(triggers, maxtrigs * sizeof(Trigger));
        }
        build = &(triggers[numtrigs]);
 
        build->tgoid = pg_trigger->oid;
        build->tgname = DatumGetCString(DirectFunctionCall1(nameout,
                                                            NameGetDatum(&pg_trigger->tgname)));
        build->tgfoid = pg_trigger->tgfoid;
        build->tgtype = pg_trigger->tgtype;
        build->tgenabled = pg_trigger->tgenabled;
        build->tgisinternal = pg_trigger->tgisinternal;
        build->tgisclone = OidIsValid(pg_trigger->tgparentid);
        build->tgconstrrelid = pg_trigger->tgconstrrelid;
        build->tgconstrindid = pg_trigger->tgconstrindid;
        build->tgconstraint = pg_trigger->tgconstraint;
        build->tgdeferrable = pg_trigger->tgdeferrable;
        build->tginitdeferred = pg_trigger->tginitdeferred;
        build->tgnargs = pg_trigger->tgnargs;
        /* tgattr is first var-width field, so OK to access directly */
        build->tgnattr = pg_trigger->tgattr.dim1;
        if (build->tgnattr > 0)
        {
            build->tgattr = (int16 *) palloc(build->tgnattr * sizeof(int16));
            memcpy(build->tgattr, &(pg_trigger->tgattr.values),
                   build->tgnattr * sizeof(int16));
        }
        else
            build->tgattr = NULL;
        if (build->tgnargs > 0)
        {
            bytea      *val;
            char       *p;
 
            val = DatumGetByteaPP(fastgetattr(htup,
                                              Anum_pg_trigger_tgargs,
                                              tgrel->rd_att, &isnull));
            if (isnull)
                elog(ERROR, "tgargs is null in trigger for relation \"%s\"",
                     RelationGetRelationName(relation));
            p = (char *) VARDATA_ANY(val);
            build->tgargs = (char **) palloc(build->tgnargs * sizeof(char *));
            for (i = 0; i < build->tgnargs; i++)
            {
                build->tgargs[i] = pstrdup(p);
                p += strlen(p) + 1;
            }
        }
        else
            build->tgargs = NULL;
 
        datum = fastgetattr(htup, Anum_pg_trigger_tgoldtable,
                            tgrel->rd_att, &isnull);
        if (!isnull)
            build->tgoldtable =
                DatumGetCString(DirectFunctionCall1(nameout, datum));
        else
            build->tgoldtable = NULL;
 
        datum = fastgetattr(htup, Anum_pg_trigger_tgnewtable,
                            tgrel->rd_att, &isnull);
        if (!isnull)
            build->tgnewtable =
                DatumGetCString(DirectFunctionCall1(nameout, datum));
        else
            build->tgnewtable = NULL;
 
        datum = fastgetattr(htup, Anum_pg_trigger_tgqual,
                            tgrel->rd_att, &isnull);
        if (!isnull)
            build->tgqual = TextDatumGetCString(datum);
        else
            build->tgqual = NULL;
 
        numtrigs++;
    }
 
    systable_endscan(tgscan);
    table_close(tgrel, AccessShareLock);
 
    /* There might not be any triggers */
    if (numtrigs == 0)
    {
        pfree(triggers);
        return;
    }
 
    /* Build trigdesc */
    trigdesc = palloc0_object(TriggerDesc);
    trigdesc->triggers = triggers;
    trigdesc->numtriggers = numtrigs;
    for (i = 0; i < numtrigs; i++)
        SetTriggerFlags(trigdesc, &(triggers[i]));
 
    /* Copy completed trigdesc into cache storage */
    oldContext = MemoryContextSwitchTo(CacheMemoryContext);
    relation->trigdesc = CopyTriggerDesc(trigdesc);
    MemoryContextSwitchTo(oldContext);
 
    /* Release working memory */
    FreeTriggerDesc(trigdesc);
}
 
/*
 * Update the TriggerDesc's hint flags to include the specified trigger
 */
static void
SetTriggerFlags(TriggerDesc *trigdesc, Trigger *trigger)
{
    int16       tgtype = trigger->tgtype;
 
    trigdesc->trig_insert_before_row |=
        TRIGGER_TYPE_MATCHES(tgtype, TRIGGER_TYPE_ROW,
                             TRIGGER_TYPE_BEFORE, TRIGGER_TYPE_INSERT);
    trigdesc->trig_insert_after_row |=
        TRIGGER_TYPE_MATCHES(tgtype, TRIGGER_TYPE_ROW,
                             TRIGGER_TYPE_AFTER, TRIGGER_TYPE_INSERT);
    trigdesc->trig_insert_instead_row |=
        TRIGGER_TYPE_MATCHES(tgtype, TRIGGER_TYPE_ROW,
                             TRIGGER_TYPE_INSTEAD, TRIGGER_TYPE_INSERT);
    trigdesc->trig_insert_before_statement |=
        TRIGGER_TYPE_MATCHES(tgtype, TRIGGER_TYPE_STATEMENT,
                             TRIGGER_TYPE_BEFORE, TRIGGER_TYPE_INSERT);
    trigdesc->trig_insert_after_statement |=
        TRIGGER_TYPE_MATCHES(tgtype, TRIGGER_TYPE_STATEMENT,
                             TRIGGER_TYPE_AFTER, TRIGGER_TYPE_INSERT);
    trigdesc->trig_update_before_row |=
        TRIGGER_TYPE_MATCHES(tgtype, TRIGGER_TYPE_ROW,
                             TRIGGER_TYPE_BEFORE, TRIGGER_TYPE_UPDATE);
    trigdesc->trig_update_after_row |=
        TRIGGER_TYPE_MATCHES(tgtype, TRIGGER_TYPE_ROW,
                             TRIGGER_TYPE_AFTER, TRIGGER_TYPE_UPDATE);
    trigdesc->trig_update_instead_row |=
        TRIGGER_TYPE_MATCHES(tgtype, TRIGGER_TYPE_ROW,
                             TRIGGER_TYPE_INSTEAD, TRIGGER_TYPE_UPDATE);
    trigdesc->trig_update_before_statement |=
        TRIGGER_TYPE_MATCHES(tgtype, TRIGGER_TYPE_STATEMENT,
                             TRIGGER_TYPE_BEFORE, TRIGGER_TYPE_UPDATE);
    trigdesc->trig_update_after_statement |=
        TRIGGER_TYPE_MATCHES(tgtype, TRIGGER_TYPE_STATEMENT,
                             TRIGGER_TYPE_AFTER, TRIGGER_TYPE_UPDATE);
    trigdesc->trig_delete_before_row |=
        TRIGGER_TYPE_MATCHES(tgtype, TRIGGER_TYPE_ROW,
                             TRIGGER_TYPE_BEFORE, TRIGGER_TYPE_DELETE);
    trigdesc->trig_delete_after_row |=
        TRIGGER_TYPE_MATCHES(tgtype, TRIGGER_TYPE_ROW,
                             TRIGGER_TYPE_AFTER, TRIGGER_TYPE_DELETE);
    trigdesc->trig_delete_instead_row |=
        TRIGGER_TYPE_MATCHES(tgtype, TRIGGER_TYPE_ROW,
                             TRIGGER_TYPE_INSTEAD, TRIGGER_TYPE_DELETE);
    trigdesc->trig_delete_before_statement |=
        TRIGGER_TYPE_MATCHES(tgtype, TRIGGER_TYPE_STATEMENT,
                             TRIGGER_TYPE_BEFORE, TRIGGER_TYPE_DELETE);
    trigdesc->trig_delete_after_statement |=
        TRIGGER_TYPE_MATCHES(tgtype, TRIGGER_TYPE_STATEMENT,
                             TRIGGER_TYPE_AFTER, TRIGGER_TYPE_DELETE);
    /* there are no row-level truncate triggers */
    trigdesc->trig_truncate_before_statement |=
        TRIGGER_TYPE_MATCHES(tgtype, TRIGGER_TYPE_STATEMENT,
                             TRIGGER_TYPE_BEFORE, TRIGGER_TYPE_TRUNCATE);
    trigdesc->trig_truncate_after_statement |=
        TRIGGER_TYPE_MATCHES(tgtype, TRIGGER_TYPE_STATEMENT,
                             TRIGGER_TYPE_AFTER, TRIGGER_TYPE_TRUNCATE);
 
    trigdesc->trig_insert_new_table |=
        (TRIGGER_FOR_INSERT(tgtype) &&
         TRIGGER_USES_TRANSITION_TABLE(trigger->tgnewtable));
    trigdesc->trig_update_old_table |=
        (TRIGGER_FOR_UPDATE(tgtype) &&
         TRIGGER_USES_TRANSITION_TABLE(trigger->tgoldtable));
    trigdesc->trig_update_new_table |=
        (TRIGGER_FOR_UPDATE(tgtype) &&
         TRIGGER_USES_TRANSITION_TABLE(trigger->tgnewtable));
    trigdesc->trig_delete_old_table |=
        (TRIGGER_FOR_DELETE(tgtype) &&
         TRIGGER_USES_TRANSITION_TABLE(trigger->tgoldtable));
}
 
/*
 * Copy a TriggerDesc data structure.
 *
 * The copy is allocated in the current memory context.
 */
TriggerDesc *
CopyTriggerDesc(TriggerDesc *trigdesc)
{
    TriggerDesc *newdesc;
    Trigger    *trigger;
    int         i;
 
    if (trigdesc == NULL || trigdesc->numtriggers <= 0)
        return NULL;
 
    newdesc = palloc_object(TriggerDesc);
    memcpy(newdesc, trigdesc, sizeof(TriggerDesc));
 
    trigger = (Trigger *) palloc(trigdesc->numtriggers * sizeof(Trigger));
    memcpy(trigger, trigdesc->triggers,
           trigdesc->numtriggers * sizeof(Trigger));
    newdesc->triggers = trigger;
 
    for (i = 0; i < trigdesc->numtriggers; i++)
    {
        trigger->tgname = pstrdup(trigger->tgname);
        if (trigger->tgnattr > 0)
        {
            int16      *newattr;
 
            newattr = (int16 *) palloc(trigger->tgnattr * sizeof(int16));
            memcpy(newattr, trigger->tgattr,
                   trigger->tgnattr * sizeof(int16));
            trigger->tgattr = newattr;
        }
        if (trigger->tgnargs > 0)
        {
            char      **newargs;
            int16       j;
 
            newargs = (char **) palloc(trigger->tgnargs * sizeof(char *));
            for (j = 0; j < trigger->tgnargs; j++)
                newargs[j] = pstrdup(trigger->tgargs[j]);
            trigger->tgargs = newargs;
        }
        if (trigger->tgqual)
            trigger->tgqual = pstrdup(trigger->tgqual);
        if (trigger->tgoldtable)
            trigger->tgoldtable = pstrdup(trigger->tgoldtable);
        if (trigger->tgnewtable)
            trigger->tgnewtable = pstrdup(trigger->tgnewtable);
        trigger++;
    }
 
    return newdesc;
}
 
/*
 * Free a TriggerDesc data structure.
 */
void
FreeTriggerDesc(TriggerDesc *trigdesc)
{
    Trigger    *trigger;
    int         i;
 
    if (trigdesc == NULL)
        return;
 
    trigger = trigdesc->triggers;
    for (i = 0; i < trigdesc->numtriggers; i++)
    {
        pfree(trigger->tgname);
        if (trigger->tgnattr > 0)
            pfree(trigger->tgattr);
        if (trigger->tgnargs > 0)
        {
            while (--(trigger->tgnargs) >= 0)
                pfree(trigger->tgargs[trigger->tgnargs]);
            pfree(trigger->tgargs);
        }
        if (trigger->tgqual)
            pfree(trigger->tgqual);
        if (trigger->tgoldtable)
            pfree(trigger->tgoldtable);
        if (trigger->tgnewtable)
            pfree(trigger->tgnewtable);
        trigger++;
    }
    pfree(trigdesc->triggers);
    pfree(trigdesc);
}
 
/*
 * Compare two TriggerDesc structures for logical equality.
 */
#ifdef NOT_USED
bool
equalTriggerDescs(TriggerDesc *trigdesc1, TriggerDesc *trigdesc2)
{
    int         i,
                j;
 
    /*
     * We need not examine the hint flags, just the trigger array itself; if
     * we have the same triggers with the same types, the flags should match.
     *
     * As of 7.3 we assume trigger set ordering is significant in the
     * comparison; so we just compare corresponding slots of the two sets.
     *
     * Note: comparing the stringToNode forms of the WHEN clauses means that
     * parse column locations will affect the result.  This is okay as long as
     * this function is only used for detecting exact equality, as for example
     * in checking for staleness of a cache entry.
     */
    if (trigdesc1 != NULL)
    {
        if (trigdesc2 == NULL)
            return false;
        if (trigdesc1->numtriggers != trigdesc2->numtriggers)
            return false;
        for (i = 0; i < trigdesc1->numtriggers; i++)
        {
            Trigger    *trig1 = trigdesc1->triggers + i;
            Trigger    *trig2 = trigdesc2->triggers + i;
 
            if (trig1->tgoid != trig2->tgoid)
                return false;
            if (strcmp(trig1->tgname, trig2->tgname) != 0)
                return false;
            if (trig1->tgfoid != trig2->tgfoid)
                return false;
            if (trig1->tgtype != trig2->tgtype)
                return false;
            if (trig1->tgenabled != trig2->tgenabled)
                return false;
            if (trig1->tgisinternal != trig2->tgisinternal)
                return false;
            if (trig1->tgisclone != trig2->tgisclone)
                return false;
            if (trig1->tgconstrrelid != trig2->tgconstrrelid)
                return false;
            if (trig1->tgconstrindid != trig2->tgconstrindid)
                return false;
            if (trig1->tgconstraint != trig2->tgconstraint)
                return false;
            if (trig1->tgdeferrable != trig2->tgdeferrable)
                return false;
            if (trig1->tginitdeferred != trig2->tginitdeferred)
                return false;
            if (trig1->tgnargs != trig2->tgnargs)
                return false;
            if (trig1->tgnattr != trig2->tgnattr)
                return false;
            if (trig1->tgnattr > 0 &&
                memcmp(trig1->tgattr, trig2->tgattr,
                       trig1->tgnattr * sizeof(int16)) != 0)
                return false;
            for (j = 0; j < trig1->tgnargs; j++)
                if (strcmp(trig1->tgargs[j], trig2->tgargs[j]) != 0)
                    return false;
            if (trig1->tgqual == NULL && trig2->tgqual == NULL)
                 /* ok */ ;
            else if (trig1->tgqual == NULL || trig2->tgqual == NULL)
                return false;
            else if (strcmp(trig1->tgqual, trig2->tgqual) != 0)
                return false;
            if (trig1->tgoldtable == NULL && trig2->tgoldtable == NULL)
                 /* ok */ ;
            else if (trig1->tgoldtable == NULL || trig2->tgoldtable == NULL)
                return false;
            else if (strcmp(trig1->tgoldtable, trig2->tgoldtable) != 0)
                return false;
            if (trig1->tgnewtable == NULL && trig2->tgnewtable == NULL)
                 /* ok */ ;
            else if (trig1->tgnewtable == NULL || trig2->tgnewtable == NULL)
                return false;
            else if (strcmp(trig1->tgnewtable, trig2->tgnewtable) != 0)
                return false;
        }
    }
    else if (trigdesc2 != NULL)
        return false;
    return true;
}
#endif                          /* NOT_USED */
 
/*
 * Check if there is a row-level trigger with transition tables that prevents
 * a table from becoming an inheritance child or partition.  Return the name
 * of the first such incompatible trigger, or NULL if there is none.
 */
const char *
FindTriggerIncompatibleWithInheritance(TriggerDesc *trigdesc)
{
    if (trigdesc != NULL)
    {
        int         i;
 
        for (i = 0; i < trigdesc->numtriggers; ++i)
        {
            Trigger    *trigger = &trigdesc->triggers[i];
 
            if (!TRIGGER_FOR_ROW(trigger->tgtype))
                continue;
            if (trigger->tgoldtable != NULL || trigger->tgnewtable != NULL)
                return trigger->tgname;
        }
    }
 
    return NULL;
}
 
/*
 * Call a trigger function.
 *
 *      trigdata: trigger descriptor.
 *      tgindx: trigger's index in finfo and instr arrays.
 *      finfo: array of cached trigger function call information.
 *      instr: optional array of EXPLAIN ANALYZE instrumentation state.
 *      per_tuple_context: memory context to execute the function in.
 *
 * Returns the tuple (or NULL) as returned by the function.
 */
static HeapTuple
ExecCallTriggerFunc(TriggerData *trigdata,
                    int tgindx,
                    FmgrInfo *finfo,
                    Instrumentation *instr,
                    MemoryContext per_tuple_context)
{
    LOCAL_FCINFO(fcinfo, 0);
    PgStat_FunctionCallUsage fcusage;
    Datum       result;
    MemoryContext oldContext;
 
    /*
     * Protect against code paths that may fail to initialize transition table
     * info.
     */
    Assert(((TRIGGER_FIRED_BY_INSERT(trigdata->tg_event) ||
             TRIGGER_FIRED_BY_UPDATE(trigdata->tg_event) ||
             TRIGGER_FIRED_BY_DELETE(trigdata->tg_event)) &&
            TRIGGER_FIRED_AFTER(trigdata->tg_event) &&
            !(trigdata->tg_event & AFTER_TRIGGER_DEFERRABLE) &&
            !(trigdata->tg_event & AFTER_TRIGGER_INITDEFERRED)) ||
           (trigdata->tg_oldtable == NULL && trigdata->tg_newtable == NULL));
 
    finfo += tgindx;
 
    /*
     * We cache fmgr lookup info, to avoid making the lookup again on each
     * call.
     */
    if (finfo->fn_oid == InvalidOid)
        fmgr_info(trigdata->tg_trigger->tgfoid, finfo);
 
    Assert(finfo->fn_oid == trigdata->tg_trigger->tgfoid);
 
    /*
     * If doing EXPLAIN ANALYZE, start charging time to this trigger.
     */
    if (instr)
        InstrStartNode(instr + tgindx);
 
    /*
     * Do the function evaluation in the per-tuple memory context, so that
     * leaked memory will be reclaimed once per tuple. Note in particular that
     * any new tuple created by the trigger function will live till the end of
     * the tuple cycle.
     */
    oldContext = MemoryContextSwitchTo(per_tuple_context);
 
    /*
     * Call the function, passing no arguments but setting a context.
     */
    InitFunctionCallInfoData(*fcinfo, finfo, 0,
                             InvalidOid, (Node *) trigdata, NULL);
 
    pgstat_init_function_usage(fcinfo, &fcusage);
 
    MyTriggerDepth++;
    PG_TRY();
    {
        result = FunctionCallInvoke(fcinfo);
    }
    PG_FINALLY();
    {
        MyTriggerDepth--;
    }
    PG_END_TRY();
 
    pgstat_end_function_usage(&fcusage, true);
 
    MemoryContextSwitchTo(oldContext);
 
    /*
     * Trigger protocol allows function to return a null pointer, but NOT to
     * set the isnull result flag.
     */
    if (fcinfo->isnull)
        ereport(ERROR,
                (errcode(ERRCODE_E_R_I_E_TRIGGER_PROTOCOL_VIOLATED),
                 errmsg("trigger function %u returned null value",
                        fcinfo->flinfo->fn_oid)));
 
    /*
     * If doing EXPLAIN ANALYZE, stop charging time to this trigger, and count
     * one "tuple returned" (really the number of firings).
     */
    if (instr)
        InstrStopNode(instr + tgindx, 1);
 
    return (HeapTuple) DatumGetPointer(result);
}
 
void
ExecBSInsertTriggers(EState *estate, ResultRelInfo *relinfo)
{
    TriggerDesc *trigdesc;
    int         i;
    TriggerData LocTriggerData = {0};
 
    trigdesc = relinfo->ri_TrigDesc;
 
    if (trigdesc == NULL)
        return;
    if (!trigdesc->trig_insert_before_statement)
        return;
 
    /* no-op if we already fired BS triggers in this context */
    if (before_stmt_triggers_fired(RelationGetRelid(relinfo->ri_RelationDesc),
                                   CMD_INSERT))
        return;
 
    LocTriggerData.type = T_TriggerData;
    LocTriggerData.tg_event = TRIGGER_EVENT_INSERT |
        TRIGGER_EVENT_BEFORE;
    LocTriggerData.tg_relation = relinfo->ri_RelationDesc;
    for (i = 0; i < trigdesc->numtriggers; i++)
    {
        Trigger    *trigger = &trigdesc->triggers[i];
        HeapTuple   newtuple;
 
        if (!TRIGGER_TYPE_MATCHES(trigger->tgtype,
                                  TRIGGER_TYPE_STATEMENT,
                                  TRIGGER_TYPE_BEFORE,
                                  TRIGGER_TYPE_INSERT))
            continue;
        if (!TriggerEnabled(estate, relinfo, trigger, LocTriggerData.tg_event,
                            NULL, NULL, NULL))
            continue;
 
        LocTriggerData.tg_trigger = trigger;
        newtuple = ExecCallTriggerFunc(&LocTriggerData,
                                       i,
                                       relinfo->ri_TrigFunctions,
                                       relinfo->ri_TrigInstrument,
                                       GetPerTupleMemoryContext(estate));
 
        if (newtuple)
            ereport(ERROR,
                    (errcode(ERRCODE_E_R_I_E_TRIGGER_PROTOCOL_VIOLATED),
                     errmsg("BEFORE STATEMENT trigger cannot return a value")));
    }
}
 
void
ExecASInsertTriggers(EState *estate, ResultRelInfo *relinfo,
                     TransitionCaptureState *transition_capture)
{
    TriggerDesc *trigdesc = relinfo->ri_TrigDesc;
 
    if (trigdesc && trigdesc->trig_insert_after_statement)
        AfterTriggerSaveEvent(estate, relinfo, NULL, NULL,
                              TRIGGER_EVENT_INSERT,
                              false, NULL, NULL, NIL, NULL, transition_capture,
                              false);
}
 
bool
ExecBRInsertTriggers(EState *estate, ResultRelInfo *relinfo,
                     TupleTableSlot *slot)
{
    TriggerDesc *trigdesc = relinfo->ri_TrigDesc;
    HeapTuple   newtuple = NULL;
    bool        should_free;
    TriggerData LocTriggerData = {0};
    int         i;
 
    LocTriggerData.type = T_TriggerData;
    LocTriggerData.tg_event = TRIGGER_EVENT_INSERT |
        TRIGGER_EVENT_ROW |
        TRIGGER_EVENT_BEFORE;
    LocTriggerData.tg_relation = relinfo->ri_RelationDesc;
    for (i = 0; i < trigdesc->numtriggers; i++)
    {
        Trigger    *trigger = &trigdesc->triggers[i];
        HeapTuple   oldtuple;
 
        if (!TRIGGER_TYPE_MATCHES(trigger->tgtype,
                                  TRIGGER_TYPE_ROW,
                                  TRIGGER_TYPE_BEFORE,
                                  TRIGGER_TYPE_INSERT))
            continue;
        if (!TriggerEnabled(estate, relinfo, trigger, LocTriggerData.tg_event,
                            NULL, NULL, slot))
            continue;
 
        if (!newtuple)
            newtuple = ExecFetchSlotHeapTuple(slot, true, &should_free);
 
        LocTriggerData.tg_trigslot = slot;
        LocTriggerData.tg_trigtuple = oldtuple = newtuple;
        LocTriggerData.tg_trigger = trigger;
        newtuple = ExecCallTriggerFunc(&LocTriggerData,
                                       i,
                                       relinfo->ri_TrigFunctions,
                                       relinfo->ri_TrigInstrument,
                                       GetPerTupleMemoryContext(estate));
        if (newtuple == NULL)
        {
            if (should_free)
                heap_freetuple(oldtuple);
            return false;       /* "do nothing" */
        }
        else if (newtuple != oldtuple)
        {
            newtuple = check_modified_virtual_generated(RelationGetDescr(relinfo->ri_RelationDesc), newtuple);
 
            ExecForceStoreHeapTuple(newtuple, slot, false);
 
            /*
             * After a tuple in a partition goes through a trigger, the user
             * could have changed the partition key enough that the tuple no
             * longer fits the partition.  Verify that.
             */
            if (trigger->tgisclone &&
                !ExecPartitionCheck(relinfo, slot, estate, false))
                ereport(ERROR,
                        (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
                         errmsg("moving row to another partition during a BEFORE FOR EACH ROW trigger is not supported"),
                         errdetail("Before executing trigger \"%s\", the row was to be in partition \"%s.%s\".",
                                   trigger->tgname,
                                   get_namespace_name(RelationGetNamespace(relinfo->ri_RelationDesc)),
                                   RelationGetRelationName(relinfo->ri_RelationDesc))));
 
            if (should_free)
                heap_freetuple(oldtuple);
 
            /* signal tuple should be re-fetched if used */
            newtuple = NULL;
        }
    }
 
    return true;
}
 
void
ExecARInsertTriggers(EState *estate, ResultRelInfo *relinfo,
                     TupleTableSlot *slot, List *recheckIndexes,
                     TransitionCaptureState *transition_capture)
{
    TriggerDesc *trigdesc = relinfo->ri_TrigDesc;
 
    if (relinfo->ri_FdwRoutine && transition_capture &&
        transition_capture->tcs_insert_new_table)
    {
        Assert(relinfo->ri_RootResultRelInfo);
        ereport(ERROR,
                (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
                 errmsg("cannot collect transition tuples from child foreign tables")));
    }
 
    if ((trigdesc && trigdesc->trig_insert_after_row) ||
        (transition_capture && transition_capture->tcs_insert_new_table))
        AfterTriggerSaveEvent(estate, relinfo, NULL, NULL,
                              TRIGGER_EVENT_INSERT,
                              true, NULL, slot,
                              recheckIndexes, NULL,
                              transition_capture,
                              false);
}
 
bool
ExecIRInsertTriggers(EState *estate, ResultRelInfo *relinfo,
                     TupleTableSlot *slot)
{
    TriggerDesc *trigdesc = relinfo->ri_TrigDesc;
    HeapTuple   newtuple = NULL;
    bool        should_free;
    TriggerData LocTriggerData = {0};
    int         i;
 
    LocTriggerData.type = T_TriggerData;
    LocTriggerData.tg_event = TRIGGER_EVENT_INSERT |
        TRIGGER_EVENT_ROW |
        TRIGGER_EVENT_INSTEAD;
    LocTriggerData.tg_relation = relinfo->ri_RelationDesc;
    for (i = 0; i < trigdesc->numtriggers; i++)
    {
        Trigger    *trigger = &trigdesc->triggers[i];
        HeapTuple   oldtuple;
 
        if (!TRIGGER_TYPE_MATCHES(trigger->tgtype,
                                  TRIGGER_TYPE_ROW,
                                  TRIGGER_TYPE_INSTEAD,
                                  TRIGGER_TYPE_INSERT))
            continue;
        if (!TriggerEnabled(estate, relinfo, trigger, LocTriggerData.tg_event,
                            NULL, NULL, slot))
            continue;
 
        if (!newtuple)
            newtuple = ExecFetchSlotHeapTuple(slot, true, &should_free);
 
        LocTriggerData.tg_trigslot = slot;
        LocTriggerData.tg_trigtuple = oldtuple = newtuple;
        LocTriggerData.tg_trigger = trigger;
        newtuple = ExecCallTriggerFunc(&LocTriggerData,
                                       i,
                                       relinfo->ri_TrigFunctions,
                                       relinfo->ri_TrigInstrument,
                                       GetPerTupleMemoryContext(estate));
        if (newtuple == NULL)
        {
            if (should_free)
                heap_freetuple(oldtuple);
            return false;       /* "do nothing" */
        }
        else if (newtuple != oldtuple)
        {
            ExecForceStoreHeapTuple(newtuple, slot, false);
 
            if (should_free)
                heap_freetuple(oldtuple);
 
            /* signal tuple should be re-fetched if used */
            newtuple = NULL;
        }
    }
 
    return true;
}
 
void
ExecBSDeleteTriggers(EState *estate, ResultRelInfo *relinfo)
{
    TriggerDesc *trigdesc;
    int         i;
    TriggerData LocTriggerData = {0};
 
    trigdesc = relinfo->ri_TrigDesc;
 
    if (trigdesc == NULL)
        return;
    if (!trigdesc->trig_delete_before_statement)
        return;
 
    /* no-op if we already fired BS triggers in this context */
    if (before_stmt_triggers_fired(RelationGetRelid(relinfo->ri_RelationDesc),
                                   CMD_DELETE))
        return;
 
    LocTriggerData.type = T_TriggerData;
    LocTriggerData.tg_event = TRIGGER_EVENT_DELETE |
        TRIGGER_EVENT_BEFORE;
    LocTriggerData.tg_relation = relinfo->ri_RelationDesc;
    for (i = 0; i < trigdesc->numtriggers; i++)
    {
        Trigger    *trigger = &trigdesc->triggers[i];
        HeapTuple   newtuple;
 
        if (!TRIGGER_TYPE_MATCHES(trigger->tgtype,
                                  TRIGGER_TYPE_STATEMENT,
                                  TRIGGER_TYPE_BEFORE,
                                  TRIGGER_TYPE_DELETE))
            continue;
        if (!TriggerEnabled(estate, relinfo, trigger, LocTriggerData.tg_event,
                            NULL, NULL, NULL))
            continue;
 
        LocTriggerData.tg_trigger = trigger;
        newtuple = ExecCallTriggerFunc(&LocTriggerData,
                                       i,
                                       relinfo->ri_TrigFunctions,
                                       relinfo->ri_TrigInstrument,
                                       GetPerTupleMemoryContext(estate));
 
        if (newtuple)
            ereport(ERROR,
                    (errcode(ERRCODE_E_R_I_E_TRIGGER_PROTOCOL_VIOLATED),
                     errmsg("BEFORE STATEMENT trigger cannot return a value")));
    }
}
 
void
ExecASDeleteTriggers(EState *estate, ResultRelInfo *relinfo,
                     TransitionCaptureState *transition_capture)
{
    TriggerDesc *trigdesc = relinfo->ri_TrigDesc;
 
    if (trigdesc && trigdesc->trig_delete_after_statement)
        AfterTriggerSaveEvent(estate, relinfo, NULL, NULL,
                              TRIGGER_EVENT_DELETE,
                              false, NULL, NULL, NIL, NULL, transition_capture,
                              false);
}
 
/*
 * Execute BEFORE ROW DELETE triggers.
 *
 * True indicates caller can proceed with the delete.  False indicates caller
 * need to suppress the delete and additionally if requested, we need to pass
 * back the concurrently updated tuple if any.
 */
bool
ExecBRDeleteTriggers(EState *estate, EPQState *epqstate,
                     ResultRelInfo *relinfo,
                     ItemPointer tupleid,
                     HeapTuple fdw_trigtuple,
                     TupleTableSlot **epqslot,
                     TM_Result *tmresult,
                     TM_FailureData *tmfd,
                     bool is_merge_delete)
{
    TupleTableSlot *slot = ExecGetTriggerOldSlot(estate, relinfo);
    TriggerDesc *trigdesc = relinfo->ri_TrigDesc;
    bool        result = true;
    TriggerData LocTriggerData = {0};
    HeapTuple   trigtuple;
    bool        should_free = false;
    int         i;
 
    Assert(HeapTupleIsValid(fdw_trigtuple) ^ ItemPointerIsValid(tupleid));
    if (fdw_trigtuple == NULL)
    {
        TupleTableSlot *epqslot_candidate = NULL;
 
        /*
         * Get a copy of the on-disk tuple we are planning to delete.  In
         * general, if the tuple has been concurrently updated, we should
         * recheck it using EPQ.  However, if this is a MERGE DELETE action,
         * we skip this EPQ recheck and leave it to the caller (it must do
         * additional rechecking, and might end up executing a different
         * action entirely).
         */
        if (!GetTupleForTrigger(estate, epqstate, relinfo, tupleid,
                                LockTupleExclusive, slot, !is_merge_delete,
                                &epqslot_candidate, tmresult, tmfd))
            return false;
 
        /*
         * If the tuple was concurrently updated and the caller of this
         * function requested for the updated tuple, skip the trigger
         * execution.
         */
        if (epqslot_candidate != NULL && epqslot != NULL)
        {
            *epqslot = epqslot_candidate;
            return false;
        }
 
        trigtuple = ExecFetchSlotHeapTuple(slot, true, &should_free);
    }
    else
    {
        trigtuple = fdw_trigtuple;
        ExecForceStoreHeapTuple(trigtuple, slot, false);
    }
 
    LocTriggerData.type = T_TriggerData;
    LocTriggerData.tg_event = TRIGGER_EVENT_DELETE |
        TRIGGER_EVENT_ROW |
        TRIGGER_EVENT_BEFORE;
    LocTriggerData.tg_relation = relinfo->ri_RelationDesc;
    for (i = 0; i < trigdesc->numtriggers; i++)
    {
        HeapTuple   newtuple;
        Trigger    *trigger = &trigdesc->triggers[i];
 
        if (!TRIGGER_TYPE_MATCHES(trigger->tgtype,
                                  TRIGGER_TYPE_ROW,
                                  TRIGGER_TYPE_BEFORE,
                                  TRIGGER_TYPE_DELETE))
            continue;
        if (!TriggerEnabled(estate, relinfo, trigger, LocTriggerData.tg_event,
                            NULL, slot, NULL))
            continue;
 
        LocTriggerData.tg_trigslot = slot;
        LocTriggerData.tg_trigtuple = trigtuple;
        LocTriggerData.tg_trigger = trigger;
        newtuple = ExecCallTriggerFunc(&LocTriggerData,
                                       i,
                                       relinfo->ri_TrigFunctions,
                                       relinfo->ri_TrigInstrument,
                                       GetPerTupleMemoryContext(estate));
        if (newtuple == NULL)
        {
            result = false;     /* tell caller to suppress delete */
            break;
        }
        if (newtuple != trigtuple)
            heap_freetuple(newtuple);
    }
    if (should_free)
        heap_freetuple(trigtuple);
 
    return result;
}
 
/*
 * Note: is_crosspart_update must be true if the DELETE is being performed
 * as part of a cross-partition update.
 */
void
ExecARDeleteTriggers(EState *estate,
                     ResultRelInfo *relinfo,
                     ItemPointer tupleid,
                     HeapTuple fdw_trigtuple,
                     TransitionCaptureState *transition_capture,
                     bool is_crosspart_update)
{
    TriggerDesc *trigdesc = relinfo->ri_TrigDesc;
 
    if (relinfo->ri_FdwRoutine && transition_capture &&
        transition_capture->tcs_delete_old_table)
    {
        Assert(relinfo->ri_RootResultRelInfo);
        ereport(ERROR,
                (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
                 errmsg("cannot collect transition tuples from child foreign tables")));
    }
 
    if ((trigdesc && trigdesc->trig_delete_after_row) ||
        (transition_capture && transition_capture->tcs_delete_old_table))
    {
        TupleTableSlot *slot = ExecGetTriggerOldSlot(estate, relinfo);
 
        Assert(HeapTupleIsValid(fdw_trigtuple) ^ ItemPointerIsValid(tupleid));
        if (fdw_trigtuple == NULL)
            GetTupleForTrigger(estate,
                               NULL,
                               relinfo,
                               tupleid,
                               LockTupleExclusive,
                               slot,
                               false,
                               NULL,
                               NULL,
                               NULL);
        else
            ExecForceStoreHeapTuple(fdw_trigtuple, slot, false);
 
        AfterTriggerSaveEvent(estate, relinfo, NULL, NULL,
                              TRIGGER_EVENT_DELETE,
                              true, slot, NULL, NIL, NULL,
                              transition_capture,
                              is_crosspart_update);
    }
}
 
bool
ExecIRDeleteTriggers(EState *estate, ResultRelInfo *relinfo,
                     HeapTuple trigtuple)
{
    TriggerDesc *trigdesc = relinfo->ri_TrigDesc;
    TupleTableSlot *slot = ExecGetTriggerOldSlot(estate, relinfo);
    TriggerData LocTriggerData = {0};
    int         i;
 
    LocTriggerData.type = T_TriggerData;
    LocTriggerData.tg_event = TRIGGER_EVENT_DELETE |
        TRIGGER_EVENT_ROW |
        TRIGGER_EVENT_INSTEAD;
    LocTriggerData.tg_relation = relinfo->ri_RelationDesc;
 
    ExecForceStoreHeapTuple(trigtuple, slot, false);
 
    for (i = 0; i < trigdesc->numtriggers; i++)
    {
        HeapTuple   rettuple;
        Trigger    *trigger = &trigdesc->triggers[i];
 
        if (!TRIGGER_TYPE_MATCHES(trigger->tgtype,
                                  TRIGGER_TYPE_ROW,
                                  TRIGGER_TYPE_INSTEAD,
                                  TRIGGER_TYPE_DELETE))
            continue;
        if (!TriggerEnabled(estate, relinfo, trigger, LocTriggerData.tg_event,
                            NULL, slot, NULL))
            continue;
 
        LocTriggerData.tg_trigslot = slot;
        LocTriggerData.tg_trigtuple = trigtuple;
        LocTriggerData.tg_trigger = trigger;
        rettuple = ExecCallTriggerFunc(&LocTriggerData,
                                       i,
                                       relinfo->ri_TrigFunctions,
                                       relinfo->ri_TrigInstrument,
                                       GetPerTupleMemoryContext(estate));
        if (rettuple == NULL)
            return false;       /* Delete was suppressed */
        if (rettuple != trigtuple)
            heap_freetuple(rettuple);
    }
    return true;
}
 
void
ExecBSUpdateTriggers(EState *estate, ResultRelInfo *relinfo)
{
    TriggerDesc *trigdesc;
    int         i;
    TriggerData LocTriggerData = {0};
    Bitmapset  *updatedCols;
 
    trigdesc = relinfo->ri_TrigDesc;
 
    if (trigdesc == NULL)
        return;
    if (!trigdesc->trig_update_before_statement)
        return;
 
    /* no-op if we already fired BS triggers in this context */
    if (before_stmt_triggers_fired(RelationGetRelid(relinfo->ri_RelationDesc),
                                   CMD_UPDATE))
        return;
 
    /* statement-level triggers operate on the parent table */
    Assert(relinfo->ri_RootResultRelInfo == NULL);
 
    updatedCols = ExecGetAllUpdatedCols(relinfo, estate);
 
    LocTriggerData.type = T_TriggerData;
    LocTriggerData.tg_event = TRIGGER_EVENT_UPDATE |
        TRIGGER_EVENT_BEFORE;
    LocTriggerData.tg_relation = relinfo->ri_RelationDesc;
    LocTriggerData.tg_updatedcols = updatedCols;
    for (i = 0; i < trigdesc->numtriggers; i++)
    {
        Trigger    *trigger = &trigdesc->triggers[i];
        HeapTuple   newtuple;
 
        if (!TRIGGER_TYPE_MATCHES(trigger->tgtype,
                                  TRIGGER_TYPE_STATEMENT,
                                  TRIGGER_TYPE_BEFORE,
                                  TRIGGER_TYPE_UPDATE))
            continue;
        if (!TriggerEnabled(estate, relinfo, trigger, LocTriggerData.tg_event,
                            updatedCols, NULL, NULL))
            continue;
 
        LocTriggerData.tg_trigger = trigger;
        newtuple = ExecCallTriggerFunc(&LocTriggerData,
                                       i,
                                       relinfo->ri_TrigFunctions,
                                       relinfo->ri_TrigInstrument,
                                       GetPerTupleMemoryContext(estate));
 
        if (newtuple)
            ereport(ERROR,
                    (errcode(ERRCODE_E_R_I_E_TRIGGER_PROTOCOL_VIOLATED),
                     errmsg("BEFORE STATEMENT trigger cannot return a value")));
    }
}
 
void
ExecASUpdateTriggers(EState *estate, ResultRelInfo *relinfo,
                     TransitionCaptureState *transition_capture)
{
    TriggerDesc *trigdesc = relinfo->ri_TrigDesc;
 
    /* statement-level triggers operate on the parent table */
    Assert(relinfo->ri_RootResultRelInfo == NULL);
 
    if (trigdesc && trigdesc->trig_update_after_statement)
        AfterTriggerSaveEvent(estate, relinfo, NULL, NULL,
                              TRIGGER_EVENT_UPDATE,
                              false, NULL, NULL, NIL,
                              ExecGetAllUpdatedCols(relinfo, estate),
                              transition_capture,
                              false);
}
 
bool
ExecBRUpdateTriggers(EState *estate, EPQState *epqstate,
                     ResultRelInfo *relinfo,
                     ItemPointer tupleid,
                     HeapTuple fdw_trigtuple,
                     TupleTableSlot *newslot,
                     TM_Result *tmresult,
                     TM_FailureData *tmfd,
                     bool is_merge_update)
{
    TriggerDesc *trigdesc = relinfo->ri_TrigDesc;
    TupleTableSlot *oldslot = ExecGetTriggerOldSlot(estate, relinfo);
    HeapTuple   newtuple = NULL;
    HeapTuple   trigtuple;
    bool        should_free_trig = false;
    bool        should_free_new = false;
    TriggerData LocTriggerData = {0};
    int         i;
    Bitmapset  *updatedCols;
    LockTupleMode lockmode;
 
    /* Determine lock mode to use */
    lockmode = ExecUpdateLockMode(estate, relinfo);
 
    Assert(HeapTupleIsValid(fdw_trigtuple) ^ ItemPointerIsValid(tupleid));
    if (fdw_trigtuple == NULL)
    {
        TupleTableSlot *epqslot_candidate = NULL;
 
        /*
         * Get a copy of the on-disk tuple we are planning to update.  In
         * general, if the tuple has been concurrently updated, we should
         * recheck it using EPQ.  However, if this is a MERGE UPDATE action,
         * we skip this EPQ recheck and leave it to the caller (it must do
         * additional rechecking, and might end up executing a different
         * action entirely).
         */
        if (!GetTupleForTrigger(estate, epqstate, relinfo, tupleid,
                                lockmode, oldslot, !is_merge_update,
                                &epqslot_candidate, tmresult, tmfd))
            return false;       /* cancel the update action */
 
        /*
         * In READ COMMITTED isolation level it's possible that target tuple
         * was changed due to concurrent update.  In that case we have a raw
         * subplan output tuple in epqslot_candidate, and need to form a new
         * insertable tuple using ExecGetUpdateNewTuple to replace the one we
         * received in newslot.  Neither we nor our callers have any further
         * interest in the passed-in tuple, so it's okay to overwrite newslot
         * with the newer data.
         */
        if (epqslot_candidate != NULL)
        {
            TupleTableSlot *epqslot_clean;
 
            epqslot_clean = ExecGetUpdateNewTuple(relinfo, epqslot_candidate,
                                                  oldslot);
 
            /*
             * Typically, the caller's newslot was also generated by
             * ExecGetUpdateNewTuple, so that epqslot_clean will be the same
             * slot and copying is not needed.  But do the right thing if it
             * isn't.
             */
            if (unlikely(newslot != epqslot_clean))
                ExecCopySlot(newslot, epqslot_clean);
 
            /*
             * At this point newslot contains a virtual tuple that may
             * reference some fields of oldslot's tuple in some disk buffer.
             * If that tuple is in a different page than the original target
             * tuple, then our only pin on that buffer is oldslot's, and we're
             * about to release it.  Hence we'd better materialize newslot to
             * ensure it doesn't contain references into an unpinned buffer.
             * (We'd materialize it below anyway, but too late for safety.)
             */
            ExecMaterializeSlot(newslot);
        }
 
        /*
         * Here we convert oldslot to a materialized slot holding trigtuple.
         * Neither slot passed to the triggers will hold any buffer pin.
         */
        trigtuple = ExecFetchSlotHeapTuple(oldslot, true, &should_free_trig);
    }
    else
    {
        /* Put the FDW-supplied tuple into oldslot to unify the cases */
        ExecForceStoreHeapTuple(fdw_trigtuple, oldslot, false);
        trigtuple = fdw_trigtuple;
    }
 
    LocTriggerData.type = T_TriggerData;
    LocTriggerData.tg_event = TRIGGER_EVENT_UPDATE |
        TRIGGER_EVENT_ROW |
        TRIGGER_EVENT_BEFORE;
    LocTriggerData.tg_relation = relinfo->ri_RelationDesc;
    updatedCols = ExecGetAllUpdatedCols(relinfo, estate);
    LocTriggerData.tg_updatedcols = updatedCols;
    for (i = 0; i < trigdesc->numtriggers; i++)
    {
        Trigger    *trigger = &trigdesc->triggers[i];
        HeapTuple   oldtuple;
 
        if (!TRIGGER_TYPE_MATCHES(trigger->tgtype,
                                  TRIGGER_TYPE_ROW,
                                  TRIGGER_TYPE_BEFORE,
                                  TRIGGER_TYPE_UPDATE))
            continue;
        if (!TriggerEnabled(estate, relinfo, trigger, LocTriggerData.tg_event,
                            updatedCols, oldslot, newslot))
            continue;
 
        if (!newtuple)
            newtuple = ExecFetchSlotHeapTuple(newslot, true, &should_free_new);
 
        LocTriggerData.tg_trigslot = oldslot;
        LocTriggerData.tg_trigtuple = trigtuple;
        LocTriggerData.tg_newtuple = oldtuple = newtuple;
        LocTriggerData.tg_newslot = newslot;
        LocTriggerData.tg_trigger = trigger;
        newtuple = ExecCallTriggerFunc(&LocTriggerData,
                                       i,
                                       relinfo->ri_TrigFunctions,
                                       relinfo->ri_TrigInstrument,
                                       GetPerTupleMemoryContext(estate));
 
        if (newtuple == NULL)
        {
            if (should_free_trig)
                heap_freetuple(trigtuple);
            if (should_free_new)
                heap_freetuple(oldtuple);
            return false;       /* "do nothing" */
        }
        else if (newtuple != oldtuple)
        {
            newtuple = check_modified_virtual_generated(RelationGetDescr(relinfo->ri_RelationDesc), newtuple);
 
            ExecForceStoreHeapTuple(newtuple, newslot, false);
 
            /*
             * If the tuple returned by the trigger / being stored, is the old
             * row version, and the heap tuple passed to the trigger was
             * allocated locally, materialize the slot. Otherwise we might
             * free it while still referenced by the slot.
             */
            if (should_free_trig && newtuple == trigtuple)
                ExecMaterializeSlot(newslot);
 
            if (should_free_new)
                heap_freetuple(oldtuple);
 
            /* signal tuple should be re-fetched if used */
            newtuple = NULL;
        }
    }
    if (should_free_trig)
        heap_freetuple(trigtuple);
 
    return true;
}
 
/*
 * Note: 'src_partinfo' and 'dst_partinfo', when non-NULL, refer to the source
 * and destination partitions, respectively, of a cross-partition update of
 * the root partitioned table mentioned in the query, given by 'relinfo'.
 * 'tupleid' in that case refers to the ctid of the "old" tuple in the source
 * partition, and 'newslot' contains the "new" tuple in the destination
 * partition.  This interface allows to support the requirements of
 * ExecCrossPartitionUpdateForeignKey(); is_crosspart_update must be true in
 * that case.
 */
void
ExecARUpdateTriggers(EState *estate, ResultRelInfo *relinfo,
                     ResultRelInfo *src_partinfo,
                     ResultRelInfo *dst_partinfo,
                     ItemPointer tupleid,
                     HeapTuple fdw_trigtuple,
                     TupleTableSlot *newslot,
                     List *recheckIndexes,
                     TransitionCaptureState *transition_capture,
                     bool is_crosspart_update)
{
    TriggerDesc *trigdesc = relinfo->ri_TrigDesc;
 
    if (relinfo->ri_FdwRoutine && transition_capture &&
        (transition_capture->tcs_update_old_table ||
         transition_capture->tcs_update_new_table))
    {
        Assert(relinfo->ri_RootResultRelInfo);
        ereport(ERROR,
                (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
                 errmsg("cannot collect transition tuples from child foreign tables")));
    }
 
    if ((trigdesc && trigdesc->trig_update_after_row) ||
        (transition_capture &&
         (transition_capture->tcs_update_old_table ||
          transition_capture->tcs_update_new_table)))
    {
        /*
         * Note: if the UPDATE is converted into a DELETE+INSERT as part of
         * update-partition-key operation, then this function is also called
         * separately for DELETE and INSERT to capture transition table rows.
         * In such case, either old tuple or new tuple can be NULL.
         */
        TupleTableSlot *oldslot;
        ResultRelInfo *tupsrc;
 
        Assert((src_partinfo != NULL && dst_partinfo != NULL) ||
               !is_crosspart_update);
 
        tupsrc = src_partinfo ? src_partinfo : relinfo;
        oldslot = ExecGetTriggerOldSlot(estate, tupsrc);
 
        if (fdw_trigtuple == NULL && ItemPointerIsValid(tupleid))
            GetTupleForTrigger(estate,
                               NULL,
                               tupsrc,
                               tupleid,
                               LockTupleExclusive,
                               oldslot,
                               false,
                               NULL,
                               NULL,
                               NULL);
        else if (fdw_trigtuple != NULL)
            ExecForceStoreHeapTuple(fdw_trigtuple, oldslot, false);
        else
            ExecClearTuple(oldslot);
 
        AfterTriggerSaveEvent(estate, relinfo,
                              src_partinfo, dst_partinfo,
                              TRIGGER_EVENT_UPDATE,
                              true,
                              oldslot, newslot, recheckIndexes,
                              ExecGetAllUpdatedCols(relinfo, estate),
                              transition_capture,
                              is_crosspart_update);
    }
}
 
bool
ExecIRUpdateTriggers(EState *estate, ResultRelInfo *relinfo,
                     HeapTuple trigtuple, TupleTableSlot *newslot)
{
    TriggerDesc *trigdesc = relinfo->ri_TrigDesc;
    TupleTableSlot *oldslot = ExecGetTriggerOldSlot(estate, relinfo);
    HeapTuple   newtuple = NULL;
    bool        should_free;
    TriggerData LocTriggerData = {0};
    int         i;
 
    LocTriggerData.type = T_TriggerData;
    LocTriggerData.tg_event = TRIGGER_EVENT_UPDATE |
        TRIGGER_EVENT_ROW |
        TRIGGER_EVENT_INSTEAD;
    LocTriggerData.tg_relation = relinfo->ri_RelationDesc;
 
    ExecForceStoreHeapTuple(trigtuple, oldslot, false);
 
    for (i = 0; i < trigdesc->numtriggers; i++)
    {
        Trigger    *trigger = &trigdesc->triggers[i];
        HeapTuple   oldtuple;
 
        if (!TRIGGER_TYPE_MATCHES(trigger->tgtype,
                                  TRIGGER_TYPE_ROW,
                                  TRIGGER_TYPE_INSTEAD,
                                  TRIGGER_TYPE_UPDATE))
            continue;
        if (!TriggerEnabled(estate, relinfo, trigger, LocTriggerData.tg_event,
                            NULL, oldslot, newslot))
            continue;
 
        if (!newtuple)
            newtuple = ExecFetchSlotHeapTuple(newslot, true, &should_free);
 
        LocTriggerData.tg_trigslot = oldslot;
        LocTriggerData.tg_trigtuple = trigtuple;
        LocTriggerData.tg_newslot = newslot;
        LocTriggerData.tg_newtuple = oldtuple = newtuple;
 
        LocTriggerData.tg_trigger = trigger;
        newtuple = ExecCallTriggerFunc(&LocTriggerData,
                                       i,
                                       relinfo->ri_TrigFunctions,
                                       relinfo->ri_TrigInstrument,
                                       GetPerTupleMemoryContext(estate));
        if (newtuple == NULL)
        {
            return false;       /* "do nothing" */
        }
        else if (newtuple != oldtuple)
        {
            ExecForceStoreHeapTuple(newtuple, newslot, false);
 
            if (should_free)
                heap_freetuple(oldtuple);
 
            /* signal tuple should be re-fetched if used */
            newtuple = NULL;
        }
    }
 
    return true;
}
 
void
ExecBSTruncateTriggers(EState *estate, ResultRelInfo *relinfo)
{
    TriggerDesc *trigdesc;
    int         i;
    TriggerData LocTriggerData = {0};
 
    trigdesc = relinfo->ri_TrigDesc;
 
    if (trigdesc == NULL)
        return;
    if (!trigdesc->trig_truncate_before_statement)
        return;
 
    LocTriggerData.type = T_TriggerData;
    LocTriggerData.tg_event = TRIGGER_EVENT_TRUNCATE |
        TRIGGER_EVENT_BEFORE;
    LocTriggerData.tg_relation = relinfo->ri_RelationDesc;
 
    for (i = 0; i < trigdesc->numtriggers; i++)
    {
        Trigger    *trigger = &trigdesc->triggers[i];
        HeapTuple   newtuple;
 
        if (!TRIGGER_TYPE_MATCHES(trigger->tgtype,
                                  TRIGGER_TYPE_STATEMENT,
                                  TRIGGER_TYPE_BEFORE,
                                  TRIGGER_TYPE_TRUNCATE))
            continue;
        if (!TriggerEnabled(estate, relinfo, trigger, LocTriggerData.tg_event,
                            NULL, NULL, NULL))
            continue;
 
        LocTriggerData.tg_trigger = trigger;
        newtuple = ExecCallTriggerFunc(&LocTriggerData,
                                       i,
                                       relinfo->ri_TrigFunctions,
                                       relinfo->ri_TrigInstrument,
                                       GetPerTupleMemoryContext(estate));
 
        if (newtuple)
            ereport(ERROR,
                    (errcode(ERRCODE_E_R_I_E_TRIGGER_PROTOCOL_VIOLATED),
                     errmsg("BEFORE STATEMENT trigger cannot return a value")));
    }
}
 
void
ExecASTruncateTriggers(EState *estate, ResultRelInfo *relinfo)
{
    TriggerDesc *trigdesc = relinfo->ri_TrigDesc;
 
    if (trigdesc && trigdesc->trig_truncate_after_statement)
        AfterTriggerSaveEvent(estate, relinfo,
                              NULL, NULL,
                              TRIGGER_EVENT_TRUNCATE,
                              false, NULL, NULL, NIL, NULL, NULL,
                              false);
}
 
 
/*
 * Fetch tuple into "oldslot", dealing with locking and EPQ if necessary
 */
static bool
GetTupleForTrigger(EState *estate,
                   EPQState *epqstate,
                   ResultRelInfo *relinfo,
                   ItemPointer tid,
                   LockTupleMode lockmode,
                   TupleTableSlot *oldslot,
                   bool do_epq_recheck,
                   TupleTableSlot **epqslot,
                   TM_Result *tmresultp,
                   TM_FailureData *tmfdp)
{
    Relation    relation = relinfo->ri_RelationDesc;
 
    if (epqslot != NULL)
    {
        TM_Result   test;
        TM_FailureData tmfd;
        int         lockflags = 0;
 
        *epqslot = NULL;
 
        /* caller must pass an epqstate if EvalPlanQual is possible */
        Assert(epqstate != NULL);
 
        /*
         * lock tuple for update
         */
        if (!IsolationUsesXactSnapshot())
            lockflags |= TUPLE_LOCK_FLAG_FIND_LAST_VERSION;
        test = table_tuple_lock(relation, tid, estate->es_snapshot, oldslot,
                                estate->es_output_cid,
                                lockmode, LockWaitBlock,
                                lockflags,
                                &tmfd);
 
        /* Let the caller know about the status of this operation */
        if (tmresultp)
            *tmresultp = test;
        if (tmfdp)
            *tmfdp = tmfd;
 
        switch (test)
        {
            case TM_SelfModified:
 
                /*
                 * The target tuple was already updated or deleted by the
                 * current command, or by a later command in the current
                 * transaction.  We ignore the tuple in the former case, and
                 * throw error in the latter case, for the same reasons
                 * enumerated in ExecUpdate and ExecDelete in
                 * nodeModifyTable.c.
                 */
                if (tmfd.cmax != estate->es_output_cid)
                    ereport(ERROR,
                            (errcode(ERRCODE_TRIGGERED_DATA_CHANGE_VIOLATION),
                             errmsg("tuple to be updated was already modified by an operation triggered by the current command"),
                             errhint("Consider using an AFTER trigger instead of a BEFORE trigger to propagate changes to other rows.")));
 
                /* treat it as deleted; do not process */
                return false;
 
            case TM_Ok:
                if (tmfd.traversed)
                {
                    /*
                     * Recheck the tuple using EPQ, if requested.  Otherwise,
                     * just return that it was concurrently updated.
                     */
                    if (do_epq_recheck)
                    {
                        *epqslot = EvalPlanQual(epqstate,
                                                relation,
                                                relinfo->ri_RangeTableIndex,
                                                oldslot);
 
                        /*
                         * If PlanQual failed for updated tuple - we must not
                         * process this tuple!
                         */
                        if (TupIsNull(*epqslot))
                        {
                            *epqslot = NULL;
                            return false;
                        }
                    }
                    else
                    {
                        if (tmresultp)
                            *tmresultp = TM_Updated;
                        return false;
                    }
                }
                break;
 
            case TM_Updated:
                if (IsolationUsesXactSnapshot())
                    ereport(ERROR,
                            (errcode(ERRCODE_T_R_SERIALIZATION_FAILURE),
                             errmsg("could not serialize access due to concurrent update")));
                elog(ERROR, "unexpected table_tuple_lock status: %u", test);
                break;
 
            case TM_Deleted:
                if (IsolationUsesXactSnapshot())
                    ereport(ERROR,
                            (errcode(ERRCODE_T_R_SERIALIZATION_FAILURE),
                             errmsg("could not serialize access due to concurrent delete")));
                /* tuple was deleted */
                return false;
 
            case TM_Invisible:
                elog(ERROR, "attempted to lock invisible tuple");
                break;
 
            default:
                elog(ERROR, "unrecognized table_tuple_lock status: %u", test);
                return false;   /* keep compiler quiet */
        }
    }
    else
    {
        /*
         * We expect the tuple to be present, thus very simple error handling
         * suffices.
         */
        if (!table_tuple_fetch_row_version(relation, tid, SnapshotAny,
                                           oldslot))
            elog(ERROR, "failed to fetch tuple for trigger");
    }
 
    return true;
}
 
/*
 * Is trigger enabled to fire?
 */
static bool
TriggerEnabled(EState *estate, ResultRelInfo *relinfo,
               Trigger *trigger, TriggerEvent event,
               Bitmapset *modifiedCols,
               TupleTableSlot *oldslot, TupleTableSlot *newslot)
{
    /* Check replication-role-dependent enable state */
    if (SessionReplicationRole == SESSION_REPLICATION_ROLE_REPLICA)
    {
        if (trigger->tgenabled == TRIGGER_FIRES_ON_ORIGIN ||
            trigger->tgenabled == TRIGGER_DISABLED)
            return false;
    }
    else                        /* ORIGIN or LOCAL role */
    {
        if (trigger->tgenabled == TRIGGER_FIRES_ON_REPLICA ||
            trigger->tgenabled == TRIGGER_DISABLED)
            return false;
    }
 
    /*
     * Check for column-specific trigger (only possible for UPDATE, and in
     * fact we *must* ignore tgattr for other event types)
     */
    if (trigger->tgnattr > 0 && TRIGGER_FIRED_BY_UPDATE(event))
    {
        int         i;
        bool        modified;
 
        modified = false;
        for (i = 0; i < trigger->tgnattr; i++)
        {
            if (bms_is_member(trigger->tgattr[i] - FirstLowInvalidHeapAttributeNumber,
                              modifiedCols))
            {
                modified = true;
                break;
            }
        }
        if (!modified)
            return false;
    }
 
    /* Check for WHEN clause */
    if (trigger->tgqual)
    {
        ExprState **predicate;
        ExprContext *econtext;
        MemoryContext oldContext;
        int         i;
 
        Assert(estate != NULL);
 
        /*
         * trigger is an element of relinfo->ri_TrigDesc->triggers[]; find the
         * matching element of relinfo->ri_TrigWhenExprs[]
         */
        i = trigger - relinfo->ri_TrigDesc->triggers;
        predicate = &relinfo->ri_TrigWhenExprs[i];
 
        /*
         * If first time through for this WHEN expression, build expression
         * nodetrees for it.  Keep them in the per-query memory context so
         * they'll survive throughout the query.
         */
        if (*predicate == NULL)
        {
            Node       *tgqual;
 
            oldContext = MemoryContextSwitchTo(estate->es_query_cxt);
            tgqual = stringToNode(trigger->tgqual);
            tgqual = expand_generated_columns_in_expr(tgqual, relinfo->ri_RelationDesc, PRS2_OLD_VARNO);
            tgqual = expand_generated_columns_in_expr(tgqual, relinfo->ri_RelationDesc, PRS2_NEW_VARNO);
            /* Change references to OLD and NEW to INNER_VAR and OUTER_VAR */
            ChangeVarNodes(tgqual, PRS2_OLD_VARNO, INNER_VAR, 0);
            ChangeVarNodes(tgqual, PRS2_NEW_VARNO, OUTER_VAR, 0);
            /* ExecPrepareQual wants implicit-AND form */
            tgqual = (Node *) make_ands_implicit((Expr *) tgqual);
            *predicate = ExecPrepareQual((List *) tgqual, estate);
            MemoryContextSwitchTo(oldContext);
        }
 
        /*
         * We will use the EState's per-tuple context for evaluating WHEN
         * expressions (creating it if it's not already there).
         */
        econtext = GetPerTupleExprContext(estate);
 
        /*
         * Finally evaluate the expression, making the old and/or new tuples
         * available as INNER_VAR/OUTER_VAR respectively.
         */
        econtext->ecxt_innertuple = oldslot;
        econtext->ecxt_outertuple = newslot;
        if (!ExecQual(*predicate, econtext))
            return false;
    }
 
    return true;
}
 
 
/* ----------
 * After-trigger stuff
 *
 * The AfterTriggersData struct holds data about pending AFTER trigger events
 * during the current transaction tree.  (BEFORE triggers are fired
 * immediately so we don't need any persistent state about them.)  The struct
 * and most of its subsidiary data are kept in TopTransactionContext; however
 * some data that can be discarded sooner appears in the CurTransactionContext
 * of the relevant subtransaction.  Also, the individual event records are
 * kept in a separate sub-context of TopTransactionContext.  This is done
 * mainly so that it's easy to tell from a memory context dump how much space
 * is being eaten by trigger events.
 *
 * Because the list of pending events can grow large, we go to some
 * considerable effort to minimize per-event memory consumption.  The event
 * records are grouped into chunks and common data for similar events in the
 * same chunk is only stored once.
 *
 * XXX We need to be able to save the per-event data in a file if it grows too
 * large.
 * ----------
 */
 
/* Per-trigger SET CONSTRAINT status */
typedef struct SetConstraintTriggerData
{
    Oid         sct_tgoid;
    bool        sct_tgisdeferred;
} SetConstraintTriggerData;
 
typedef struct SetConstraintTriggerData *SetConstraintTrigger;
 
/*
 * SET CONSTRAINT intra-transaction status.
 *
 * We make this a single palloc'd object so it can be copied and freed easily.
 *
 * all_isset and all_isdeferred are used to keep track
 * of SET CONSTRAINTS ALL {DEFERRED, IMMEDIATE}.
 *
 * trigstates[] stores per-trigger tgisdeferred settings.
 */
typedef struct SetConstraintStateData
{
    bool        all_isset;
    bool        all_isdeferred;
    int         numstates;      /* number of trigstates[] entries in use */
    int         numalloc;       /* allocated size of trigstates[] */
    SetConstraintTriggerData trigstates[FLEXIBLE_ARRAY_MEMBER];
} SetConstraintStateData;
 
typedef SetConstraintStateData *SetConstraintState;
 
 
/*
 * Per-trigger-event data
 *
 * The actual per-event data, AfterTriggerEventData, includes DONE/IN_PROGRESS
 * status bits, up to two tuple CTIDs, and optionally two OIDs of partitions.
 * Each event record also has an associated AfterTriggerSharedData that is
 * shared across all instances of similar events within a "chunk".
 *
 * For row-level triggers, we arrange not to waste storage on unneeded ctid
 * fields.  Updates of regular tables use two; inserts and deletes of regular
 * tables use one; foreign tables always use zero and save the tuple(s) to a
 * tuplestore.  AFTER_TRIGGER_FDW_FETCH directs AfterTriggerExecute() to
 * retrieve a fresh tuple or pair of tuples from that tuplestore, while
 * AFTER_TRIGGER_FDW_REUSE directs it to use the most-recently-retrieved
 * tuple(s).  This permits storing tuples once regardless of the number of
 * row-level triggers on a foreign table.
 *
 * When updates on partitioned tables cause rows to move between partitions,
 * the OIDs of both partitions are stored too, so that the tuples can be
 * fetched; such entries are marked AFTER_TRIGGER_CP_UPDATE (for "cross-
 * partition update").
 *
 * Note that we need triggers on foreign tables to be fired in exactly the
 * order they were queued, so that the tuples come out of the tuplestore in
 * the right order.  To ensure that, we forbid deferrable (constraint)
 * triggers on foreign tables.  This also ensures that such triggers do not
 * get deferred into outer trigger query levels, meaning that it's okay to
 * destroy the tuplestore at the end of the query level.
 *
 * Statement-level triggers always bear AFTER_TRIGGER_1CTID, though they
 * require no ctid field.  We lack the flag bit space to neatly represent that
 * distinct case, and it seems unlikely to be worth much trouble.
 *
 * Note: ats_firing_id is initially zero and is set to something else when
 * AFTER_TRIGGER_IN_PROGRESS is set.  It indicates which trigger firing
 * cycle the trigger will be fired in (or was fired in, if DONE is set).
 * Although this is mutable state, we can keep it in AfterTriggerSharedData
 * because all instances of the same type of event in a given event list will
 * be fired at the same time, if they were queued between the same firing
 * cycles.  So we need only ensure that ats_firing_id is zero when attaching
 * a new event to an existing AfterTriggerSharedData record.
 */
typedef uint32 TriggerFlags;
 
#define AFTER_TRIGGER_OFFSET            0x07FFFFFF  /* must be low-order bits */
#define AFTER_TRIGGER_DONE              0x80000000
#define AFTER_TRIGGER_IN_PROGRESS       0x40000000
/* bits describing the size and tuple sources of this event */
#define AFTER_TRIGGER_FDW_REUSE         0x00000000
#define AFTER_TRIGGER_FDW_FETCH         0x20000000
#define AFTER_TRIGGER_1CTID             0x10000000
#define AFTER_TRIGGER_2CTID             0x30000000
#define AFTER_TRIGGER_CP_UPDATE         0x08000000
#define AFTER_TRIGGER_TUP_BITS          0x38000000
typedef struct AfterTriggerSharedData *AfterTriggerShared;
 
typedef struct AfterTriggerSharedData
{
    TriggerEvent ats_event;     /* event type indicator, see trigger.h */
    Oid         ats_tgoid;      /* the trigger's ID */
    Oid         ats_relid;      /* the relation it's on */
    Oid         ats_rolid;      /* role to execute the trigger */
    CommandId   ats_firing_id;  /* ID for firing cycle */
    struct AfterTriggersTableData *ats_table;   /* transition table access */
    Bitmapset  *ats_modifiedcols;   /* modified columns */
} AfterTriggerSharedData;
 
typedef struct AfterTriggerEventData *AfterTriggerEvent;
 
typedef struct AfterTriggerEventData
{
    TriggerFlags ate_flags;     /* status bits and offset to shared data */
    ItemPointerData ate_ctid1;  /* inserted, deleted, or old updated tuple */
    ItemPointerData ate_ctid2;  /* new updated tuple */
 
    /*
     * During a cross-partition update of a partitioned table, we also store
     * the OIDs of source and destination partitions that are needed to fetch
     * the old (ctid1) and the new tuple (ctid2) from, respectively.
     */
    Oid         ate_src_part;
    Oid         ate_dst_part;
} AfterTriggerEventData;
 
/* AfterTriggerEventData, minus ate_src_part, ate_dst_part */
typedef struct AfterTriggerEventDataNoOids
{
    TriggerFlags ate_flags;
    ItemPointerData ate_ctid1;
    ItemPointerData ate_ctid2;
}           AfterTriggerEventDataNoOids;
 
/* AfterTriggerEventData, minus ate_*_part and ate_ctid2 */
typedef struct AfterTriggerEventDataOneCtid
{
    TriggerFlags ate_flags;     /* status bits and offset to shared data */
    ItemPointerData ate_ctid1;  /* inserted, deleted, or old updated tuple */
}           AfterTriggerEventDataOneCtid;
 
/* AfterTriggerEventData, minus ate_*_part, ate_ctid1 and ate_ctid2 */
typedef struct AfterTriggerEventDataZeroCtids
{
    TriggerFlags ate_flags;     /* status bits and offset to shared data */
}           AfterTriggerEventDataZeroCtids;
 
#define SizeofTriggerEvent(evt) \
    (((evt)->ate_flags & AFTER_TRIGGER_TUP_BITS) == AFTER_TRIGGER_CP_UPDATE ? \
     sizeof(AfterTriggerEventData) : \
     (((evt)->ate_flags & AFTER_TRIGGER_TUP_BITS) == AFTER_TRIGGER_2CTID ? \
      sizeof(AfterTriggerEventDataNoOids) : \
      (((evt)->ate_flags & AFTER_TRIGGER_TUP_BITS) == AFTER_TRIGGER_1CTID ? \
       sizeof(AfterTriggerEventDataOneCtid) : \
       sizeof(AfterTriggerEventDataZeroCtids))))
 
#define GetTriggerSharedData(evt) \
    ((AfterTriggerShared) ((char *) (evt) + ((evt)->ate_flags & AFTER_TRIGGER_OFFSET)))
 
/*
 * To avoid palloc overhead, we keep trigger events in arrays in successively-
 * larger chunks (a slightly more sophisticated version of an expansible
 * array).  The space between CHUNK_DATA_START and freeptr is occupied by
 * AfterTriggerEventData records; the space between endfree and endptr is
 * occupied by AfterTriggerSharedData records.
 */
typedef struct AfterTriggerEventChunk
{
    struct AfterTriggerEventChunk *next;    /* list link */
    char       *freeptr;        /* start of free space in chunk */
    char       *endfree;        /* end of free space in chunk */
    char       *endptr;         /* end of chunk */
    /* event data follows here */
} AfterTriggerEventChunk;
 
#define CHUNK_DATA_START(cptr) ((char *) (cptr) + MAXALIGN(sizeof(AfterTriggerEventChunk)))
 
/* A list of events */
typedef struct AfterTriggerEventList
{
    AfterTriggerEventChunk *head;
    AfterTriggerEventChunk *tail;
    char       *tailfree;       /* freeptr of tail chunk */
} AfterTriggerEventList;
 
/* Macros to help in iterating over a list of events */
#define for_each_chunk(cptr, evtlist) \
    for (cptr = (evtlist).head; cptr != NULL; cptr = cptr->next)
#define for_each_event(eptr, cptr) \
    for (eptr = (AfterTriggerEvent) CHUNK_DATA_START(cptr); \
         (char *) eptr < (cptr)->freeptr; \
         eptr = (AfterTriggerEvent) (((char *) eptr) + SizeofTriggerEvent(eptr)))
/* Use this if no special per-chunk processing is needed */
#define for_each_event_chunk(eptr, cptr, evtlist) \
    for_each_chunk(cptr, evtlist) for_each_event(eptr, cptr)
 
/* Macros for iterating from a start point that might not be list start */
#define for_each_chunk_from(cptr) \
    for (; cptr != NULL; cptr = cptr->next)
#define for_each_event_from(eptr, cptr) \
    for (; \
         (char *) eptr < (cptr)->freeptr; \
         eptr = (AfterTriggerEvent) (((char *) eptr) + SizeofTriggerEvent(eptr)))
 
 
/*
 * All per-transaction data for the AFTER TRIGGERS module.
 *
 * AfterTriggersData has the following fields:
 *
 * firing_counter is incremented for each call of afterTriggerInvokeEvents.
 * We mark firable events with the current firing cycle's ID so that we can
 * tell which ones to work on.  This ensures sane behavior if a trigger
 * function chooses to do SET CONSTRAINTS: the inner SET CONSTRAINTS will
 * only fire those events that weren't already scheduled for firing.
 *
 * state keeps track of the transaction-local effects of SET CONSTRAINTS.
 * This is saved and restored across failed subtransactions.
 *
 * events is the current list of deferred events.  This is global across
 * all subtransactions of the current transaction.  In a subtransaction
 * abort, we know that the events added by the subtransaction are at the
 * end of the list, so it is relatively easy to discard them.  The event
 * list chunks themselves are stored in event_cxt.
 *
 * query_depth is the current depth of nested AfterTriggerBeginQuery calls
 * (-1 when the stack is empty).
 *
 * query_stack[query_depth] is the per-query-level data, including these fields:
 *
 * events is a list of AFTER trigger events queued by the current query.
 * None of these are valid until the matching AfterTriggerEndQuery call
 * occurs.  At that point we fire immediate-mode triggers, and append any
 * deferred events to the main events list.
 *
 * fdw_tuplestore is a tuplestore containing the foreign-table tuples
 * needed by events queued by the current query.  (Note: we use just one
 * tuplestore even though more than one foreign table might be involved.
 * This is okay because tuplestores don't really care what's in the tuples
 * they store; but it's possible that someday it'd break.)
 *
 * tables is a List of AfterTriggersTableData structs for target tables
 * of the current query (see below).
 *
 * maxquerydepth is just the allocated length of query_stack.
 *
 * trans_stack holds per-subtransaction data, including these fields:
 *
 * state is NULL or a pointer to a saved copy of the SET CONSTRAINTS
 * state data.  Each subtransaction level that modifies that state first
 * saves a copy, which we use to restore the state if we abort.
 *
 * events is a copy of the events head/tail pointers,
 * which we use to restore those values during subtransaction abort.
 *
 * query_depth is the subtransaction-start-time value of query_depth,
 * which we similarly use to clean up at subtransaction abort.
 *
 * firing_counter is the subtransaction-start-time value of firing_counter.
 * We use this to recognize which deferred triggers were fired (or marked
 * for firing) within an aborted subtransaction.
 *
 * We use GetCurrentTransactionNestLevel() to determine the correct array
 * index in trans_stack.  maxtransdepth is the number of allocated entries in
 * trans_stack.  (By not keeping our own stack pointer, we can avoid trouble
 * in cases where errors during subxact abort cause multiple invocations
 * of AfterTriggerEndSubXact() at the same nesting depth.)
 *
 * We create an AfterTriggersTableData struct for each target table of the
 * current query, and each operation mode (INSERT/UPDATE/DELETE), that has
 * either transition tables or statement-level triggers.  This is used to
 * hold the relevant transition tables, as well as info tracking whether
 * we already queued the statement triggers.  (We use that info to prevent
 * firing the same statement triggers more than once per statement, or really
 * once per transition table set.)  These structs, along with the transition
 * table tuplestores, live in the (sub)transaction's CurTransactionContext.
 * That's sufficient lifespan because we don't allow transition tables to be
 * used by deferrable triggers, so they only need to survive until
 * AfterTriggerEndQuery.
 */
typedef struct AfterTriggersQueryData AfterTriggersQueryData;
typedef struct AfterTriggersTransData AfterTriggersTransData;
typedef struct AfterTriggersTableData AfterTriggersTableData;
 
typedef struct AfterTriggersData
{
    CommandId   firing_counter; /* next firing ID to assign */
    SetConstraintState state;   /* the active S C state */
    AfterTriggerEventList events;   /* deferred-event list */
    MemoryContext event_cxt;    /* memory context for events, if any */
 
    /* per-query-level data: */
    AfterTriggersQueryData *query_stack;    /* array of structs shown below */
    int         query_depth;    /* current index in above array */
    int         maxquerydepth;  /* allocated len of above array */
 
    /* per-subtransaction-level data: */
    AfterTriggersTransData *trans_stack;    /* array of structs shown below */
    int         maxtransdepth;  /* allocated len of above array */
} AfterTriggersData;
 
struct AfterTriggersQueryData
{
    AfterTriggerEventList events;   /* events pending from this query */
    Tuplestorestate *fdw_tuplestore;    /* foreign tuples for said events */
    List       *tables;         /* list of AfterTriggersTableData, see below */
};
 
struct AfterTriggersTransData
{
    /* these fields are just for resetting at subtrans abort: */
    SetConstraintState state;   /* saved S C state, or NULL if not yet saved */
    AfterTriggerEventList events;   /* saved list pointer */
    int         query_depth;    /* saved query_depth */
    CommandId   firing_counter; /* saved firing_counter */
};
 
struct AfterTriggersTableData
{
    /* relid + cmdType form the lookup key for these structs: */
    Oid         relid;          /* target table's OID */
    CmdType     cmdType;        /* event type, CMD_INSERT/UPDATE/DELETE */
    bool        closed;         /* true when no longer OK to add tuples */
    bool        before_trig_done;   /* did we already queue BS triggers? */
    bool        after_trig_done;    /* did we already queue AS triggers? */
    AfterTriggerEventList after_trig_events;    /* if so, saved list pointer */
 
    /* "old" transition table for UPDATE/DELETE, if any */
    Tuplestorestate *old_tuplestore;
    /* "new" transition table for INSERT/UPDATE, if any */
    Tuplestorestate *new_tuplestore;
 
    TupleTableSlot *storeslot;  /* for converting to tuplestore's format */
};
 
static AfterTriggersData afterTriggers;
 
static void AfterTriggerExecute(EState *estate,
                                AfterTriggerEvent event,
                                ResultRelInfo *relInfo,
                                ResultRelInfo *src_relInfo,
                                ResultRelInfo *dst_relInfo,
                                TriggerDesc *trigdesc,
                                FmgrInfo *finfo,
                                Instrumentation *instr,
                                MemoryContext per_tuple_context,
                                TupleTableSlot *trig_tuple_slot1,
                                TupleTableSlot *trig_tuple_slot2);
static AfterTriggersTableData *GetAfterTriggersTableData(Oid relid,
                                                         CmdType cmdType);
static TupleTableSlot *GetAfterTriggersStoreSlot(AfterTriggersTableData *table,
                                                 TupleDesc tupdesc);
static Tuplestorestate *GetAfterTriggersTransitionTable(int event,
                                                        TupleTableSlot *oldslot,
                                                        TupleTableSlot *newslot,
                                                        TransitionCaptureState *transition_capture);
static void TransitionTableAddTuple(EState *estate,
                                    int event,
                                    TransitionCaptureState *transition_capture,
                                    ResultRelInfo *relinfo,
                                    TupleTableSlot *slot,
                                    TupleTableSlot *original_insert_tuple,
                                    Tuplestorestate *tuplestore);
static void AfterTriggerFreeQuery(AfterTriggersQueryData *qs);
static SetConstraintState SetConstraintStateCreate(int numalloc);
static SetConstraintState SetConstraintStateCopy(SetConstraintState origstate);
static SetConstraintState SetConstraintStateAddItem(SetConstraintState state,
                                                    Oid tgoid, bool tgisdeferred);
static void cancel_prior_stmt_triggers(Oid relid, CmdType cmdType, int tgevent);
 
 
/*
 * Get the FDW tuplestore for the current trigger query level, creating it
 * if necessary.
 */
static Tuplestorestate *
GetCurrentFDWTuplestore(void)
{
    Tuplestorestate *ret;
 
    ret = afterTriggers.query_stack[afterTriggers.query_depth].fdw_tuplestore;
    if (ret == NULL)
    {
        MemoryContext oldcxt;
        ResourceOwner saveResourceOwner;
 
        /*
         * Make the tuplestore valid until end of subtransaction.  We really
         * only need it until AfterTriggerEndQuery().
         */
        oldcxt = MemoryContextSwitchTo(CurTransactionContext);
        saveResourceOwner = CurrentResourceOwner;
        CurrentResourceOwner = CurTransactionResourceOwner;
 
        ret = tuplestore_begin_heap(false, false, work_mem);
 
        CurrentResourceOwner = saveResourceOwner;
        MemoryContextSwitchTo(oldcxt);
 
        afterTriggers.query_stack[afterTriggers.query_depth].fdw_tuplestore = ret;
    }
 
    return ret;
}
 
/* ----------
 * afterTriggerCheckState()
 *
 *  Returns true if the trigger event is actually in state DEFERRED.
 * ----------
 */
static bool
afterTriggerCheckState(AfterTriggerShared evtshared)
{
    Oid         tgoid = evtshared->ats_tgoid;
    SetConstraintState state = afterTriggers.state;
    int         i;
 
    /*
     * For not-deferrable triggers (i.e. normal AFTER ROW triggers and
     * constraints declared NOT DEFERRABLE), the state is always false.
     */
    if ((evtshared->ats_event & AFTER_TRIGGER_DEFERRABLE) == 0)
        return false;
 
    /*
     * If constraint state exists, SET CONSTRAINTS might have been executed
     * either for this trigger or for all triggers.
     */
    if (state != NULL)
    {
        /* Check for SET CONSTRAINTS for this specific trigger. */
        for (i = 0; i < state->numstates; i++)
        {
            if (state->trigstates[i].sct_tgoid == tgoid)
                return state->trigstates[i].sct_tgisdeferred;
        }
 
        /* Check for SET CONSTRAINTS ALL. */
        if (state->all_isset)
            return state->all_isdeferred;
    }
 
    /*
     * Otherwise return the default state for the trigger.
     */
    return ((evtshared->ats_event & AFTER_TRIGGER_INITDEFERRED) != 0);
}
 
/* ----------
 * afterTriggerCopyBitmap()
 *
 * Copy bitmap into AfterTriggerEvents memory context, which is where the after
 * trigger events are kept.
 * ----------
 */
static Bitmapset *
afterTriggerCopyBitmap(Bitmapset *src)
{
    Bitmapset  *dst;
    MemoryContext oldcxt;
 
    if (src == NULL)
        return NULL;
 
    oldcxt = MemoryContextSwitchTo(afterTriggers.event_cxt);
 
    dst = bms_copy(src);
 
    MemoryContextSwitchTo(oldcxt);
 
    return dst;
}
 
/* ----------
 * afterTriggerAddEvent()
 *
 *  Add a new trigger event to the specified queue.
 *  The passed-in event data is copied.
 * ----------
 */
static void
afterTriggerAddEvent(AfterTriggerEventList *events,
                     AfterTriggerEvent event, AfterTriggerShared evtshared)
{
    Size        eventsize = SizeofTriggerEvent(event);
    Size        needed = eventsize + sizeof(AfterTriggerSharedData);
    AfterTriggerEventChunk *chunk;
    AfterTriggerShared newshared;
    AfterTriggerEvent newevent;
 
    /*
     * If empty list or not enough room in the tail chunk, make a new chunk.
     * We assume here that a new shared record will always be needed.
     */
    chunk = events->tail;
    if (chunk == NULL ||
        chunk->endfree - chunk->freeptr < needed)
    {
        Size        chunksize;
 
        /* Create event context if we didn't already */
        if (afterTriggers.event_cxt == NULL)
            afterTriggers.event_cxt =
                AllocSetContextCreate(TopTransactionContext,
                                      "AfterTriggerEvents",
                                      ALLOCSET_DEFAULT_SIZES);
 
        /*
         * Chunk size starts at 1KB and is allowed to increase up to 1MB.
         * These numbers are fairly arbitrary, though there is a hard limit at
         * AFTER_TRIGGER_OFFSET; else we couldn't link event records to their
         * shared records using the available space in ate_flags.  Another
         * constraint is that if the chunk size gets too huge, the search loop
         * below would get slow given a (not too common) usage pattern with
         * many distinct event types in a chunk.  Therefore, we double the
         * preceding chunk size only if there weren't too many shared records
         * in the preceding chunk; otherwise we halve it.  This gives us some
         * ability to adapt to the actual usage pattern of the current query
         * while still having large chunk sizes in typical usage.  All chunk
         * sizes used should be MAXALIGN multiples, to ensure that the shared
         * records will be aligned safely.
         */
#define MIN_CHUNK_SIZE 1024
#define MAX_CHUNK_SIZE (1024*1024)
 
#if MAX_CHUNK_SIZE > (AFTER_TRIGGER_OFFSET+1)
#error MAX_CHUNK_SIZE must not exceed AFTER_TRIGGER_OFFSET
#endif
 
        if (chunk == NULL)
            chunksize = MIN_CHUNK_SIZE;
        else
        {
            /* preceding chunk size... */
            chunksize = chunk->endptr - (char *) chunk;
            /* check number of shared records in preceding chunk */
            if ((chunk->endptr - chunk->endfree) <=
                (100 * sizeof(AfterTriggerSharedData)))
                chunksize *= 2; /* okay, double it */
            else
                chunksize /= 2; /* too many shared records */
            chunksize = Min(chunksize, MAX_CHUNK_SIZE);
        }
        chunk = MemoryContextAlloc(afterTriggers.event_cxt, chunksize);
        chunk->next = NULL;
        chunk->freeptr = CHUNK_DATA_START(chunk);
        chunk->endptr = chunk->endfree = (char *) chunk + chunksize;
        Assert(chunk->endfree - chunk->freeptr >= needed);
 
        if (events->tail == NULL)
        {
            Assert(events->head == NULL);
            events->head = chunk;
        }
        else
            events->tail->next = chunk;
        events->tail = chunk;
        /* events->tailfree is now out of sync, but we'll fix it below */
    }
 
    /*
     * Try to locate a matching shared-data record already in the chunk. If
     * none, make a new one. The search begins with the most recently added
     * record, since newer ones are most likely to match.
     */
    for (newshared = (AfterTriggerShared) chunk->endfree;
         (char *) newshared < chunk->endptr;
         newshared++)
    {
        /* compare fields roughly by probability of them being different */
        if (newshared->ats_tgoid == evtshared->ats_tgoid &&
            newshared->ats_event == evtshared->ats_event &&
            newshared->ats_firing_id == 0 &&
            newshared->ats_table == evtshared->ats_table &&
            newshared->ats_relid == evtshared->ats_relid &&
            newshared->ats_rolid == evtshared->ats_rolid &&
            bms_equal(newshared->ats_modifiedcols,
                      evtshared->ats_modifiedcols))
            break;
    }
    if ((char *) newshared >= chunk->endptr)
    {
        newshared = ((AfterTriggerShared) chunk->endfree) - 1;
        *newshared = *evtshared;
        /* now we must make a suitably-long-lived copy of the bitmap */
        newshared->ats_modifiedcols = afterTriggerCopyBitmap(evtshared->ats_modifiedcols);
        newshared->ats_firing_id = 0;   /* just to be sure */
        chunk->endfree = (char *) newshared;
    }
 
    /* Insert the data */
    newevent = (AfterTriggerEvent) chunk->freeptr;
    memcpy(newevent, event, eventsize);
    /* ... and link the new event to its shared record */
    newevent->ate_flags &= ~AFTER_TRIGGER_OFFSET;
    newevent->ate_flags |= (char *) newshared - (char *) newevent;
 
    chunk->freeptr += eventsize;
    events->tailfree = chunk->freeptr;
}
 
/* ----------
 * afterTriggerFreeEventList()
 *
 *  Free all the event storage in the given list.
 * ----------
 */
static void
afterTriggerFreeEventList(AfterTriggerEventList *events)
{
    AfterTriggerEventChunk *chunk;
 
    while ((chunk = events->head) != NULL)
    {
        events->head = chunk->next;
        pfree(chunk);
    }
    events->tail = NULL;
    events->tailfree = NULL;
}
 
/* ----------
 * afterTriggerRestoreEventList()
 *
 *  Restore an event list to its prior length, removing all the events
 *  added since it had the value old_events.
 * ----------
 */
static void
afterTriggerRestoreEventList(AfterTriggerEventList *events,
                             const AfterTriggerEventList *old_events)
{
    AfterTriggerEventChunk *chunk;
    AfterTriggerEventChunk *next_chunk;
 
    if (old_events->tail == NULL)
    {
        /* restoring to a completely empty state, so free everything */
        afterTriggerFreeEventList(events);
    }
    else
    {
        *events = *old_events;
        /* free any chunks after the last one we want to keep */
        for (chunk = events->tail->next; chunk != NULL; chunk = next_chunk)
        {
            next_chunk = chunk->next;
            pfree(chunk);
        }
        /* and clean up the tail chunk to be the right length */
        events->tail->next = NULL;
        events->tail->freeptr = events->tailfree;
 
        /*
         * We don't make any effort to remove now-unused shared data records.
         * They might still be useful, anyway.
         */
    }
}
 
/* ----------
 * afterTriggerDeleteHeadEventChunk()
 *
 *  Remove the first chunk of events from the query level's event list.
 *  Keep any event list pointers elsewhere in the query level's data
 *  structures in sync.
 * ----------
 */
static void
afterTriggerDeleteHeadEventChunk(AfterTriggersQueryData *qs)
{
    AfterTriggerEventChunk *target = qs->events.head;
    ListCell   *lc;
 
    Assert(target && target->next);
 
    /*
     * First, update any pointers in the per-table data, so that they won't be
     * dangling.  Resetting obsoleted pointers to NULL will make
     * cancel_prior_stmt_triggers start from the list head, which is fine.
     */
    foreach(lc, qs->tables)
    {
        AfterTriggersTableData *table = (AfterTriggersTableData *) lfirst(lc);
 
        if (table->after_trig_done &&
            table->after_trig_events.tail == target)
        {
            table->after_trig_events.head = NULL;
            table->after_trig_events.tail = NULL;
            table->after_trig_events.tailfree = NULL;
        }
    }
 
    /* Now we can flush the head chunk */
    qs->events.head = target->next;
    pfree(target);
}
 
 
/* ----------
 * AfterTriggerExecute()
 *
 *  Fetch the required tuples back from the heap and fire one
 *  single trigger function.
 *
 *  Frequently, this will be fired many times in a row for triggers of
 *  a single relation.  Therefore, we cache the open relation and provide
 *  fmgr lookup cache space at the caller level.  (For triggers fired at
 *  the end of a query, we can even piggyback on the executor's state.)
 *
 *  When fired for a cross-partition update of a partitioned table, the old
 *  tuple is fetched using 'src_relInfo' (the source leaf partition) and
 *  the new tuple using 'dst_relInfo' (the destination leaf partition), though
 *  both are converted into the root partitioned table's format before passing
 *  to the trigger function.
 *
 *  event: event currently being fired.
 *  relInfo: result relation for event.
 *  src_relInfo: source partition of a cross-partition update
 *  dst_relInfo: its destination partition
 *  trigdesc: working copy of rel's trigger info.
 *  finfo: array of fmgr lookup cache entries (one per trigger in trigdesc).
 *  instr: array of EXPLAIN ANALYZE instrumentation nodes (one per trigger),
 *      or NULL if no instrumentation is wanted.
 *  per_tuple_context: memory context to call trigger function in.
 *  trig_tuple_slot1: scratch slot for tg_trigtuple (foreign tables only)
 *  trig_tuple_slot2: scratch slot for tg_newtuple (foreign tables only)
 * ----------
 */
static void
AfterTriggerExecute(EState *estate,
                    AfterTriggerEvent event,
                    ResultRelInfo *relInfo,
                    ResultRelInfo *src_relInfo,
                    ResultRelInfo *dst_relInfo,
                    TriggerDesc *trigdesc,
                    FmgrInfo *finfo, Instrumentation *instr,
                    MemoryContext per_tuple_context,
                    TupleTableSlot *trig_tuple_slot1,
                    TupleTableSlot *trig_tuple_slot2)
{
    Relation    rel = relInfo->ri_RelationDesc;
    Relation    src_rel = src_relInfo->ri_RelationDesc;
    Relation    dst_rel = dst_relInfo->ri_RelationDesc;
    AfterTriggerShared evtshared = GetTriggerSharedData(event);
    Oid         tgoid = evtshared->ats_tgoid;
    TriggerData LocTriggerData = {0};
    Oid         save_rolid;
    int         save_sec_context;
    HeapTuple   rettuple;
    int         tgindx;
    bool        should_free_trig = false;
    bool        should_free_new = false;
 
    /*
     * Locate trigger in trigdesc.  It might not be present, and in fact the
     * trigdesc could be NULL, if the trigger was dropped since the event was
     * queued.  In that case, silently do nothing.
     */
    if (trigdesc == NULL)
        return;
    for (tgindx = 0; tgindx < trigdesc->numtriggers; tgindx++)
    {
        if (trigdesc->triggers[tgindx].tgoid == tgoid)
        {
            LocTriggerData.tg_trigger = &(trigdesc->triggers[tgindx]);
            break;
        }
    }
    if (LocTriggerData.tg_trigger == NULL)
        return;
 
    /*
     * If doing EXPLAIN ANALYZE, start charging time to this trigger. We want
     * to include time spent re-fetching tuples in the trigger cost.
     */
    if (instr)
        InstrStartNode(instr + tgindx);
 
    /*
     * Fetch the required tuple(s).
     */
    switch (event->ate_flags & AFTER_TRIGGER_TUP_BITS)
    {
        case AFTER_TRIGGER_FDW_FETCH:
            {
                Tuplestorestate *fdw_tuplestore = GetCurrentFDWTuplestore();
 
                if (!tuplestore_gettupleslot(fdw_tuplestore, true, false,
                                             trig_tuple_slot1))
                    elog(ERROR, "failed to fetch tuple1 for AFTER trigger");
 
                if ((evtshared->ats_event & TRIGGER_EVENT_OPMASK) ==
                    TRIGGER_EVENT_UPDATE &&
                    !tuplestore_gettupleslot(fdw_tuplestore, true, false,
                                             trig_tuple_slot2))
                    elog(ERROR, "failed to fetch tuple2 for AFTER trigger");
            }
            pg_fallthrough;
        case AFTER_TRIGGER_FDW_REUSE:
 
            /*
             * Store tuple in the slot so that tg_trigtuple does not reference
             * tuplestore memory.  (It is formally possible for the trigger
             * function to queue trigger events that add to the same
             * tuplestore, which can push other tuples out of memory.)  The
             * distinction is academic, because we start with a minimal tuple
             * that is stored as a heap tuple, constructed in different memory
             * context, in the slot anyway.
             */
            LocTriggerData.tg_trigslot = trig_tuple_slot1;
            LocTriggerData.tg_trigtuple =
                ExecFetchSlotHeapTuple(trig_tuple_slot1, true, &should_free_trig);
 
            if ((evtshared->ats_event & TRIGGER_EVENT_OPMASK) ==
                TRIGGER_EVENT_UPDATE)
            {
                LocTriggerData.tg_newslot = trig_tuple_slot2;
                LocTriggerData.tg_newtuple =
                    ExecFetchSlotHeapTuple(trig_tuple_slot2, true, &should_free_new);
            }
            else
            {
                LocTriggerData.tg_newtuple = NULL;
            }
            break;
 
        default:
            if (ItemPointerIsValid(&(event->ate_ctid1)))
            {
                TupleTableSlot *src_slot = ExecGetTriggerOldSlot(estate,
                                                                 src_relInfo);
 
                if (!table_tuple_fetch_row_version(src_rel,
                                                   &(event->ate_ctid1),
                                                   SnapshotAny,
                                                   src_slot))
                    elog(ERROR, "failed to fetch tuple1 for AFTER trigger");
 
                /*
                 * Store the tuple fetched from the source partition into the
                 * target (root partitioned) table slot, converting if needed.
                 */
                if (src_relInfo != relInfo)
                {
                    TupleConversionMap *map = ExecGetChildToRootMap(src_relInfo);
 
                    LocTriggerData.tg_trigslot = ExecGetTriggerOldSlot(estate, relInfo);
                    if (map)
                    {
                        execute_attr_map_slot(map->attrMap,
                                              src_slot,
                                              LocTriggerData.tg_trigslot);
                    }
                    else
                        ExecCopySlot(LocTriggerData.tg_trigslot, src_slot);
                }
                else
                    LocTriggerData.tg_trigslot = src_slot;
                LocTriggerData.tg_trigtuple =
                    ExecFetchSlotHeapTuple(LocTriggerData.tg_trigslot, false, &should_free_trig);
            }
            else
            {
                LocTriggerData.tg_trigtuple = NULL;
            }
 
            /* don't touch ctid2 if not there */
            if (((event->ate_flags & AFTER_TRIGGER_TUP_BITS) == AFTER_TRIGGER_2CTID ||
                 (event->ate_flags & AFTER_TRIGGER_CP_UPDATE)) &&
                ItemPointerIsValid(&(event->ate_ctid2)))
            {
                TupleTableSlot *dst_slot = ExecGetTriggerNewSlot(estate,
                                                                 dst_relInfo);
 
                if (!table_tuple_fetch_row_version(dst_rel,
                                                   &(event->ate_ctid2),
                                                   SnapshotAny,
                                                   dst_slot))
                    elog(ERROR, "failed to fetch tuple2 for AFTER trigger");
 
                /*
                 * Store the tuple fetched from the destination partition into
                 * the target (root partitioned) table slot, converting if
                 * needed.
                 */
                if (dst_relInfo != relInfo)
                {
                    TupleConversionMap *map = ExecGetChildToRootMap(dst_relInfo);
 
                    LocTriggerData.tg_newslot = ExecGetTriggerNewSlot(estate, relInfo);
                    if (map)
                    {
                        execute_attr_map_slot(map->attrMap,
                                              dst_slot,
                                              LocTriggerData.tg_newslot);
                    }
                    else
                        ExecCopySlot(LocTriggerData.tg_newslot, dst_slot);
                }
                else
                    LocTriggerData.tg_newslot = dst_slot;
                LocTriggerData.tg_newtuple =
                    ExecFetchSlotHeapTuple(LocTriggerData.tg_newslot, false, &should_free_new);
            }
            else
            {
                LocTriggerData.tg_newtuple = NULL;
            }
    }
 
    /*
     * Set up the tuplestore information to let the trigger have access to
     * transition tables.  When we first make a transition table available to
     * a trigger, mark it "closed" so that it cannot change anymore.  If any
     * additional events of the same type get queued in the current trigger
     * query level, they'll go into new transition tables.
     */
    LocTriggerData.tg_oldtable = LocTriggerData.tg_newtable = NULL;
    if (evtshared->ats_table)
    {
        if (LocTriggerData.tg_trigger->tgoldtable)
        {
            LocTriggerData.tg_oldtable = evtshared->ats_table->old_tuplestore;
            evtshared->ats_table->closed = true;
        }
 
        if (LocTriggerData.tg_trigger->tgnewtable)
        {
            LocTriggerData.tg_newtable = evtshared->ats_table->new_tuplestore;
            evtshared->ats_table->closed = true;
        }
    }
 
    /*
     * Setup the remaining trigger information
     */
    LocTriggerData.type = T_TriggerData;
    LocTriggerData.tg_event =
        evtshared->ats_event & (TRIGGER_EVENT_OPMASK | TRIGGER_EVENT_ROW);
    LocTriggerData.tg_relation = rel;
    if (TRIGGER_FOR_UPDATE(LocTriggerData.tg_trigger->tgtype))
        LocTriggerData.tg_updatedcols = evtshared->ats_modifiedcols;
 
    MemoryContextReset(per_tuple_context);
 
    /*
     * If necessary, become the role that was active when the trigger got
     * queued.  Note that the role might have been dropped since the trigger
     * was queued, but if that is a problem, we will get an error later.
     * Checking here would still leave a race condition.
     */
    GetUserIdAndSecContext(&save_rolid, &save_sec_context);
    if (save_rolid != evtshared->ats_rolid)
        SetUserIdAndSecContext(evtshared->ats_rolid,
                               save_sec_context | SECURITY_LOCAL_USERID_CHANGE);
 
    /*
     * Call the trigger and throw away any possibly returned updated tuple.
     * (Don't let ExecCallTriggerFunc measure EXPLAIN time.)
     */
    rettuple = ExecCallTriggerFunc(&LocTriggerData,
                                   tgindx,
                                   finfo,
                                   NULL,
                                   per_tuple_context);
    if (rettuple != NULL &&
        rettuple != LocTriggerData.tg_trigtuple &&
        rettuple != LocTriggerData.tg_newtuple)
        heap_freetuple(rettuple);
 
    /* Restore the current role if necessary */
    if (save_rolid != evtshared->ats_rolid)
        SetUserIdAndSecContext(save_rolid, save_sec_context);
 
    /*
     * Release resources
     */
    if (should_free_trig)
        heap_freetuple(LocTriggerData.tg_trigtuple);
    if (should_free_new)
        heap_freetuple(LocTriggerData.tg_newtuple);
 
    /* don't clear slots' contents if foreign table */
    if (trig_tuple_slot1 == NULL)
    {
        if (LocTriggerData.tg_trigslot)
            ExecClearTuple(LocTriggerData.tg_trigslot);
        if (LocTriggerData.tg_newslot)
            ExecClearTuple(LocTriggerData.tg_newslot);
    }
 
    /*
     * If doing EXPLAIN ANALYZE, stop charging time to this trigger, and count
     * one "tuple returned" (really the number of firings).
     */
    if (instr)
        InstrStopNode(instr + tgindx, 1);
}
 
 
/*
 * afterTriggerMarkEvents()
 *
 *  Scan the given event list for not yet invoked events.  Mark the ones
 *  that can be invoked now with the current firing ID.
 *
 *  If move_list isn't NULL, events that are not to be invoked now are
 *  transferred to move_list.
 *
 *  When immediate_only is true, do not invoke currently-deferred triggers.
 *  (This will be false only at main transaction exit.)
 *
 *  Returns true if any invokable events were found.
 */
static bool
afterTriggerMarkEvents(AfterTriggerEventList *events,
                       AfterTriggerEventList *move_list,
                       bool immediate_only)
{
    bool        found = false;
    bool        deferred_found = false;
    AfterTriggerEvent event;
    AfterTriggerEventChunk *chunk;
 
    for_each_event_chunk(event, chunk, *events)
    {
        AfterTriggerShared evtshared = GetTriggerSharedData(event);
        bool        defer_it = false;
 
        if (!(event->ate_flags &
              (AFTER_TRIGGER_DONE | AFTER_TRIGGER_IN_PROGRESS)))
        {
            /*
             * This trigger hasn't been called or scheduled yet. Check if we
             * should call it now.
             */
            if (immediate_only && afterTriggerCheckState(evtshared))
            {
                defer_it = true;
            }
            else
            {
                /*
                 * Mark it as to be fired in this firing cycle.
                 */
                evtshared->ats_firing_id = afterTriggers.firing_counter;
                event->ate_flags |= AFTER_TRIGGER_IN_PROGRESS;
                found = true;
            }
        }
 
        /*
         * If it's deferred, move it to move_list, if requested.
         */
        if (defer_it && move_list != NULL)
        {
            deferred_found = true;
            /* add it to move_list */
            afterTriggerAddEvent(move_list, event, evtshared);
            /* mark original copy "done" so we don't do it again */
            event->ate_flags |= AFTER_TRIGGER_DONE;
        }
    }
 
    /*
     * We could allow deferred triggers if, before the end of the
     * security-restricted operation, we were to verify that a SET CONSTRAINTS
     * ... IMMEDIATE has fired all such triggers.  For now, don't bother.
     */
    if (deferred_found && InSecurityRestrictedOperation())
        ereport(ERROR,
                (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
                 errmsg("cannot fire deferred trigger within security-restricted operation")));
 
    return found;
}
 
/*
 * afterTriggerInvokeEvents()
 *
 *  Scan the given event list for events that are marked as to be fired
 *  in the current firing cycle, and fire them.
 *
 *  If estate isn't NULL, we use its result relation info to avoid repeated
 *  openings and closing of trigger target relations.  If it is NULL, we
 *  make one locally to cache the info in case there are multiple trigger
 *  events per rel.
 *
 *  When delete_ok is true, it's safe to delete fully-processed events.
 *  (We are not very tense about that: we simply reset a chunk to be empty
 *  if all its events got fired.  The objective here is just to avoid useless
 *  rescanning of events when a trigger queues new events during transaction
 *  end, so it's not necessary to worry much about the case where only
 *  some events are fired.)
 *
 *  Returns true if no unfired events remain in the list (this allows us
 *  to avoid repeating afterTriggerMarkEvents).
 */
static bool
afterTriggerInvokeEvents(AfterTriggerEventList *events,
                         CommandId firing_id,
                         EState *estate,
                         bool delete_ok)
{
    bool        all_fired = true;
    AfterTriggerEventChunk *chunk;
    MemoryContext per_tuple_context;
    bool        local_estate = false;
    ResultRelInfo *rInfo = NULL;
    Relation    rel = NULL;
    TriggerDesc *trigdesc = NULL;
    FmgrInfo   *finfo = NULL;
    Instrumentation *instr = NULL;
    TupleTableSlot *slot1 = NULL,
               *slot2 = NULL;
 
    /* Make a local EState if need be */
    if (estate == NULL)
    {
        estate = CreateExecutorState();
        local_estate = true;
    }
 
    /* Make a per-tuple memory context for trigger function calls */
    per_tuple_context =
        AllocSetContextCreate(CurrentMemoryContext,
                              "AfterTriggerTupleContext",
                              ALLOCSET_DEFAULT_SIZES);
 
    for_each_chunk(chunk, *events)
    {
        AfterTriggerEvent event;
        bool        all_fired_in_chunk = true;
 
        for_each_event(event, chunk)
        {
            AfterTriggerShared evtshared = GetTriggerSharedData(event);
 
            /*
             * Is it one for me to fire?
             */
            if ((event->ate_flags & AFTER_TRIGGER_IN_PROGRESS) &&
                evtshared->ats_firing_id == firing_id)
            {
                ResultRelInfo *src_rInfo,
                           *dst_rInfo;
 
                /*
                 * So let's fire it... but first, find the correct relation if
                 * this is not the same relation as before.
                 */
                if (rel == NULL || RelationGetRelid(rel) != evtshared->ats_relid)
                {
                    rInfo = ExecGetTriggerResultRel(estate, evtshared->ats_relid,
                                                    NULL);
                    rel = rInfo->ri_RelationDesc;
                    /* Catch calls with insufficient relcache refcounting */
                    Assert(!RelationHasReferenceCountZero(rel));
                    trigdesc = rInfo->ri_TrigDesc;
                    /* caution: trigdesc could be NULL here */
                    finfo = rInfo->ri_TrigFunctions;
                    instr = rInfo->ri_TrigInstrument;
                    if (slot1 != NULL)
                    {
                        ExecDropSingleTupleTableSlot(slot1);
                        ExecDropSingleTupleTableSlot(slot2);
                        slot1 = slot2 = NULL;
                    }
                    if (rel->rd_rel->relkind == RELKIND_FOREIGN_TABLE)
                    {
                        slot1 = MakeSingleTupleTableSlot(rel->rd_att,
                                                         &TTSOpsMinimalTuple);
                        slot2 = MakeSingleTupleTableSlot(rel->rd_att,
                                                         &TTSOpsMinimalTuple);
                    }
                }
 
                /*
                 * Look up source and destination partition result rels of a
                 * cross-partition update event.
                 */
                if ((event->ate_flags & AFTER_TRIGGER_TUP_BITS) ==
                    AFTER_TRIGGER_CP_UPDATE)
                {
                    Assert(OidIsValid(event->ate_src_part) &&
                           OidIsValid(event->ate_dst_part));
                    src_rInfo = ExecGetTriggerResultRel(estate,
                                                        event->ate_src_part,
                                                        rInfo);
                    dst_rInfo = ExecGetTriggerResultRel(estate,
                                                        event->ate_dst_part,
                                                        rInfo);
                }
                else
                    src_rInfo = dst_rInfo = rInfo;
 
                /*
                 * Fire it.  Note that the AFTER_TRIGGER_IN_PROGRESS flag is
                 * still set, so recursive examinations of the event list
                 * won't try to re-fire it.
                 */
                AfterTriggerExecute(estate, event, rInfo,
                                    src_rInfo, dst_rInfo,
                                    trigdesc, finfo, instr,
                                    per_tuple_context, slot1, slot2);
 
                /*
                 * Mark the event as done.
                 */
                event->ate_flags &= ~AFTER_TRIGGER_IN_PROGRESS;
                event->ate_flags |= AFTER_TRIGGER_DONE;
            }
            else if (!(event->ate_flags & AFTER_TRIGGER_DONE))
            {
                /* something remains to be done */
                all_fired = all_fired_in_chunk = false;
            }
        }
 
        /* Clear the chunk if delete_ok and nothing left of interest */
        if (delete_ok && all_fired_in_chunk)
        {
            chunk->freeptr = CHUNK_DATA_START(chunk);
            chunk->endfree = chunk->endptr;
 
            /*
             * If it's last chunk, must sync event list's tailfree too.  Note
             * that delete_ok must NOT be passed as true if there could be
             * additional AfterTriggerEventList values pointing at this event
             * list, since we'd fail to fix their copies of tailfree.
             */
            if (chunk == events->tail)
                events->tailfree = chunk->freeptr;
        }
    }
    if (slot1 != NULL)
    {
        ExecDropSingleTupleTableSlot(slot1);
        ExecDropSingleTupleTableSlot(slot2);
    }
 
    /* Release working resources */
    MemoryContextDelete(per_tuple_context);
 
    if (local_estate)
    {
        ExecCloseResultRelations(estate);
        ExecResetTupleTable(estate->es_tupleTable, false);
        FreeExecutorState(estate);
    }
 
    return all_fired;
}
 
 
/*
 * GetAfterTriggersTableData
 *
 * Find or create an AfterTriggersTableData struct for the specified
 * trigger event (relation + operation type).  Ignore existing structs
 * marked "closed"; we don't want to put any additional tuples into them,
 * nor change their stmt-triggers-fired state.
 *
 * Note: the AfterTriggersTableData list is allocated in the current
 * (sub)transaction's CurTransactionContext.  This is OK because
 * we don't need it to live past AfterTriggerEndQuery.
 */
static AfterTriggersTableData *
GetAfterTriggersTableData(Oid relid, CmdType cmdType)
{
    AfterTriggersTableData *table;
    AfterTriggersQueryData *qs;
    MemoryContext oldcxt;
    ListCell   *lc;
 
    /* At this level, cmdType should not be, eg, CMD_MERGE */
    Assert(cmdType == CMD_INSERT ||
           cmdType == CMD_UPDATE ||
           cmdType == CMD_DELETE);
 
    /* Caller should have ensured query_depth is OK. */
    Assert(afterTriggers.query_depth >= 0 &&
           afterTriggers.query_depth < afterTriggers.maxquerydepth);
    qs = &afterTriggers.query_stack[afterTriggers.query_depth];
 
    foreach(lc, qs->tables)
    {
        table = (AfterTriggersTableData *) lfirst(lc);
        if (table->relid == relid && table->cmdType == cmdType &&
            !table->closed)
            return table;
    }
 
    oldcxt = MemoryContextSwitchTo(CurTransactionContext);
 
    table = palloc0_object(AfterTriggersTableData);
    table->relid = relid;
    table->cmdType = cmdType;
    qs->tables = lappend(qs->tables, table);
 
    MemoryContextSwitchTo(oldcxt);
 
    return table;
}
 
/*
 * Returns a TupleTableSlot suitable for holding the tuples to be put
 * into AfterTriggersTableData's transition table tuplestores.
 */
static TupleTableSlot *
GetAfterTriggersStoreSlot(AfterTriggersTableData *table,
                          TupleDesc tupdesc)
{
    /* Create it if not already done. */
    if (!table->storeslot)
    {
        MemoryContext oldcxt;
 
        /*
         * We need this slot only until AfterTriggerEndQuery, but making it
         * last till end-of-subxact is good enough.  It'll be freed by
         * AfterTriggerFreeQuery().  However, the passed-in tupdesc might have
         * a different lifespan, so we'd better make a copy of that.
         */
        oldcxt = MemoryContextSwitchTo(CurTransactionContext);
        tupdesc = CreateTupleDescCopy(tupdesc);
        table->storeslot = MakeSingleTupleTableSlot(tupdesc, &TTSOpsVirtual);
        MemoryContextSwitchTo(oldcxt);
    }
 
    return table->storeslot;
}
 
/*
 * MakeTransitionCaptureState
 *
 * Make a TransitionCaptureState object for the given TriggerDesc, target
 * relation, and operation type.  The TCS object holds all the state needed
 * to decide whether to capture tuples in transition tables.
 *
 * If there are no triggers in 'trigdesc' that request relevant transition
 * tables, then return NULL.
 *
 * The resulting object can be passed to the ExecAR* functions.  When
 * dealing with child tables, the caller can set tcs_original_insert_tuple
 * to avoid having to reconstruct the original tuple in the root table's
 * format.
 *
 * Note that we copy the flags from a parent table into this struct (rather
 * than subsequently using the relation's TriggerDesc directly) so that we can
 * use it to control collection of transition tuples from child tables.
 *
 * Per SQL spec, all operations of the same kind (INSERT/UPDATE/DELETE)
 * on the same table during one query should share one transition table.
 * Therefore, the Tuplestores are owned by an AfterTriggersTableData struct
 * looked up using the table OID + CmdType, and are merely referenced by
 * the TransitionCaptureState objects we hand out to callers.
 */
TransitionCaptureState *
MakeTransitionCaptureState(TriggerDesc *trigdesc, Oid relid, CmdType cmdType)
{
    TransitionCaptureState *state;
    bool        need_old_upd,
                need_new_upd,
                need_old_del,
                need_new_ins;
    AfterTriggersTableData *ins_table;
    AfterTriggersTableData *upd_table;
    AfterTriggersTableData *del_table;
    MemoryContext oldcxt;
    ResourceOwner saveResourceOwner;
 
    if (trigdesc == NULL)
        return NULL;
 
    /* Detect which table(s) we need. */
    switch (cmdType)
    {
        case CMD_INSERT:
            need_old_upd = need_old_del = need_new_upd = false;
            need_new_ins = trigdesc->trig_insert_new_table;
            break;
        case CMD_UPDATE:
            need_old_upd = trigdesc->trig_update_old_table;
            need_new_upd = trigdesc->trig_update_new_table;
            need_old_del = need_new_ins = false;
            break;
        case CMD_DELETE:
            need_old_del = trigdesc->trig_delete_old_table;
            need_old_upd = need_new_upd = need_new_ins = false;
            break;
        case CMD_MERGE:
            need_old_upd = trigdesc->trig_update_old_table;
            need_new_upd = trigdesc->trig_update_new_table;
            need_old_del = trigdesc->trig_delete_old_table;
            need_new_ins = trigdesc->trig_insert_new_table;
            break;
        default:
            elog(ERROR, "unexpected CmdType: %d", (int) cmdType);
            /* keep compiler quiet */
            need_old_upd = need_new_upd = need_old_del = need_new_ins = false;
            break;
    }
    if (!need_old_upd && !need_new_upd && !need_new_ins && !need_old_del)
        return NULL;
 
    /* Check state, like AfterTriggerSaveEvent. */
    if (afterTriggers.query_depth < 0)
        elog(ERROR, "MakeTransitionCaptureState() called outside of query");
 
    /* Be sure we have enough space to record events at this query depth. */
    if (afterTriggers.query_depth >= afterTriggers.maxquerydepth)
        AfterTriggerEnlargeQueryState();
 
    /*
     * Find or create AfterTriggersTableData struct(s) to hold the
     * tuplestore(s).  If there's a matching struct but it's marked closed,
     * ignore it; we need a newer one.
     *
     * Note: MERGE must use the same AfterTriggersTableData structs as INSERT,
     * UPDATE, and DELETE, so that any MERGE'd tuples are added to the same
     * tuplestores as tuples from any INSERT, UPDATE, or DELETE commands
     * running in the same top-level command (e.g., in a writable CTE).
     *
     * Note: the AfterTriggersTableData list, as well as the tuplestores, are
     * allocated in the current (sub)transaction's CurTransactionContext, and
     * the tuplestores are managed by the (sub)transaction's resource owner.
     * This is sufficient lifespan because we do not allow triggers using
     * transition tables to be deferrable; they will be fired during
     * AfterTriggerEndQuery, after which it's okay to delete the data.
     */
    if (need_new_ins)
        ins_table = GetAfterTriggersTableData(relid, CMD_INSERT);
    else
        ins_table = NULL;
 
    if (need_old_upd || need_new_upd)
        upd_table = GetAfterTriggersTableData(relid, CMD_UPDATE);
    else
        upd_table = NULL;
 
    if (need_old_del)
        del_table = GetAfterTriggersTableData(relid, CMD_DELETE);
    else
        del_table = NULL;
 
    /* Now create required tuplestore(s), if we don't have them already. */
    oldcxt = MemoryContextSwitchTo(CurTransactionContext);
    saveResourceOwner = CurrentResourceOwner;
    CurrentResourceOwner = CurTransactionResourceOwner;
 
    if (need_old_upd && upd_table->old_tuplestore == NULL)
        upd_table->old_tuplestore = tuplestore_begin_heap(false, false, work_mem);
    if (need_new_upd && upd_table->new_tuplestore == NULL)
        upd_table->new_tuplestore = tuplestore_begin_heap(false, false, work_mem);
    if (need_old_del && del_table->old_tuplestore == NULL)
        del_table->old_tuplestore = tuplestore_begin_heap(false, false, work_mem);
    if (need_new_ins && ins_table->new_tuplestore == NULL)
        ins_table->new_tuplestore = tuplestore_begin_heap(false, false, work_mem);
 
    CurrentResourceOwner = saveResourceOwner;
    MemoryContextSwitchTo(oldcxt);
 
    /* Now build the TransitionCaptureState struct, in caller's context */
    state = palloc0_object(TransitionCaptureState);
    state->tcs_delete_old_table = need_old_del;
    state->tcs_update_old_table = need_old_upd;
    state->tcs_update_new_table = need_new_upd;
    state->tcs_insert_new_table = need_new_ins;
    state->tcs_insert_private = ins_table;
    state->tcs_update_private = upd_table;
    state->tcs_delete_private = del_table;
 
    return state;
}
 
 
/* ----------
 * AfterTriggerBeginXact()
 *
 *  Called at transaction start (either BEGIN or implicit for single
 *  statement outside of transaction block).
 * ----------
 */
void
AfterTriggerBeginXact(void)
{
    /*
     * Initialize after-trigger state structure to empty
     */
    afterTriggers.firing_counter = (CommandId) 1;   /* mustn't be 0 */
    afterTriggers.query_depth = -1;
 
    /*
     * Verify that there is no leftover state remaining.  If these assertions
     * trip, it means that AfterTriggerEndXact wasn't called or didn't clean
     * up properly.
     */
    Assert(afterTriggers.state == NULL);
    Assert(afterTriggers.query_stack == NULL);
    Assert(afterTriggers.maxquerydepth == 0);
    Assert(afterTriggers.event_cxt == NULL);
    Assert(afterTriggers.events.head == NULL);
    Assert(afterTriggers.trans_stack == NULL);
    Assert(afterTriggers.maxtransdepth == 0);
}
 
 
/* ----------
 * AfterTriggerBeginQuery()
 *
 *  Called just before we start processing a single query within a
 *  transaction (or subtransaction).  Most of the real work gets deferred
 *  until somebody actually tries to queue a trigger event.
 * ----------
 */
void
AfterTriggerBeginQuery(void)
{
    /* Increase the query stack depth */
    afterTriggers.query_depth++;
}
 
 
/* ----------
 * AfterTriggerEndQuery()
 *
 *  Called after one query has been completely processed. At this time
 *  we invoke all AFTER IMMEDIATE trigger events queued by the query, and
 *  transfer deferred trigger events to the global deferred-trigger list.
 *
 *  Note that this must be called BEFORE closing down the executor
 *  with ExecutorEnd, because we make use of the EState's info about
 *  target relations.  Normally it is called from ExecutorFinish.
 * ----------
 */
void
AfterTriggerEndQuery(EState *estate)
{
    AfterTriggersQueryData *qs;
 
    /* Must be inside a query, too */
    Assert(afterTriggers.query_depth >= 0);
 
    /*
     * If we never even got as far as initializing the event stack, there
     * certainly won't be any events, so exit quickly.
     */
    if (afterTriggers.query_depth >= afterTriggers.maxquerydepth)
    {
        afterTriggers.query_depth--;
        return;
    }
 
    /*
     * Process all immediate-mode triggers queued by the query, and move the
     * deferred ones to the main list of deferred events.
     *
     * Notice that we decide which ones will be fired, and put the deferred
     * ones on the main list, before anything is actually fired.  This ensures
     * reasonably sane behavior if a trigger function does SET CONSTRAINTS ...
     * IMMEDIATE: all events we have decided to defer will be available for it
     * to fire.
     *
     * We loop in case a trigger queues more events at the same query level.
     * Ordinary trigger functions, including all PL/pgSQL trigger functions,
     * will instead fire any triggers in a dedicated query level.  Foreign key
     * enforcement triggers do add to the current query level, thanks to their
     * passing fire_triggers = false to SPI_execute_snapshot().  Other
     * C-language triggers might do likewise.
     *
     * If we find no firable events, we don't have to increment
     * firing_counter.
     */
    qs = &afterTriggers.query_stack[afterTriggers.query_depth];
 
    for (;;)
    {
        if (afterTriggerMarkEvents(&qs->events, &afterTriggers.events, true))
        {
            CommandId   firing_id = afterTriggers.firing_counter++;
            AfterTriggerEventChunk *oldtail = qs->events.tail;
 
            if (afterTriggerInvokeEvents(&qs->events, firing_id, estate, false))
                break;          /* all fired */
 
            /*
             * Firing a trigger could result in query_stack being repalloc'd,
             * so we must recalculate qs after each afterTriggerInvokeEvents
             * call.  Furthermore, it's unsafe to pass delete_ok = true here,
             * because that could cause afterTriggerInvokeEvents to try to
             * access qs->events after the stack has been repalloc'd.
             */
            qs = &afterTriggers.query_stack[afterTriggers.query_depth];
 
            /*
             * We'll need to scan the events list again.  To reduce the cost
             * of doing so, get rid of completely-fired chunks.  We know that
             * all events were marked IN_PROGRESS or DONE at the conclusion of
             * afterTriggerMarkEvents, so any still-interesting events must
             * have been added after that, and so must be in the chunk that
             * was then the tail chunk, or in later chunks.  So, zap all
             * chunks before oldtail.  This is approximately the same set of
             * events we would have gotten rid of by passing delete_ok = true.
             */
            Assert(oldtail != NULL);
            while (qs->events.head != oldtail)
                afterTriggerDeleteHeadEventChunk(qs);
        }
        else
            break;
    }
 
    /* Release query-level-local storage, including tuplestores if any */
    AfterTriggerFreeQuery(&afterTriggers.query_stack[afterTriggers.query_depth]);
 
    afterTriggers.query_depth--;
}
 
 
/*
 * AfterTriggerFreeQuery
 *  Release subsidiary storage for a trigger query level.
 *  This includes closing down tuplestores.
 *  Note: it's important for this to be safe if interrupted by an error
 *  and then called again for the same query level.
 */
static void
AfterTriggerFreeQuery(AfterTriggersQueryData *qs)
{
    Tuplestorestate *ts;
    List       *tables;
    ListCell   *lc;
 
    /* Drop the trigger events */
    afterTriggerFreeEventList(&qs->events);
 
    /* Drop FDW tuplestore if any */
    ts = qs->fdw_tuplestore;
    qs->fdw_tuplestore = NULL;
    if (ts)
        tuplestore_end(ts);
 
    /* Release per-table subsidiary storage */
    tables = qs->tables;
    foreach(lc, tables)
    {
        AfterTriggersTableData *table = (AfterTriggersTableData *) lfirst(lc);
 
        ts = table->old_tuplestore;
        table->old_tuplestore = NULL;
        if (ts)
            tuplestore_end(ts);
        ts = table->new_tuplestore;
        table->new_tuplestore = NULL;
        if (ts)
            tuplestore_end(ts);
        if (table->storeslot)
        {
            TupleTableSlot *slot = table->storeslot;
 
            table->storeslot = NULL;
            ExecDropSingleTupleTableSlot(slot);
        }
    }
 
    /*
     * Now free the AfterTriggersTableData structs and list cells.  Reset list
     * pointer first; if list_free_deep somehow gets an error, better to leak
     * that storage than have an infinite loop.
     */
    qs->tables = NIL;
    list_free_deep(tables);
}
 
 
/* ----------
 * AfterTriggerFireDeferred()
 *
 *  Called just before the current transaction is committed. At this
 *  time we invoke all pending DEFERRED triggers.
 *
 *  It is possible for other modules to queue additional deferred triggers
 *  during pre-commit processing; therefore xact.c may have to call this
 *  multiple times.
 * ----------
 */
void
AfterTriggerFireDeferred(void)
{
    AfterTriggerEventList *events;
    bool        snap_pushed = false;
 
    /* Must not be inside a query */
    Assert(afterTriggers.query_depth == -1);
 
    /*
     * If there are any triggers to fire, make sure we have set a snapshot for
     * them to use.  (Since PortalRunUtility doesn't set a snap for COMMIT, we
     * can't assume ActiveSnapshot is valid on entry.)
     */
    events = &afterTriggers.events;
    if (events->head != NULL)
    {
        PushActiveSnapshot(GetTransactionSnapshot());
        snap_pushed = true;
    }
 
    /*
     * Run all the remaining triggers.  Loop until they are all gone, in case
     * some trigger queues more for us to do.
     */
    while (afterTriggerMarkEvents(events, NULL, false))
    {
        CommandId   firing_id = afterTriggers.firing_counter++;
 
        if (afterTriggerInvokeEvents(events, firing_id, NULL, true))
            break;              /* all fired */
    }
 
    /*
     * We don't bother freeing the event list, since it will go away anyway
     * (and more efficiently than via pfree) in AfterTriggerEndXact.
     */
 
    if (snap_pushed)
        PopActiveSnapshot();
}
 
 
/* ----------
 * AfterTriggerEndXact()
 *
 *  The current transaction is finishing.
 *
 *  Any unfired triggers are canceled so we simply throw
 *  away anything we know.
 *
 *  Note: it is possible for this to be called repeatedly in case of
 *  error during transaction abort; therefore, do not complain if
 *  already closed down.
 * ----------
 */
void
AfterTriggerEndXact(bool isCommit)
{
    /*
     * Forget the pending-events list.
     *
     * Since all the info is in TopTransactionContext or children thereof, we
     * don't really need to do anything to reclaim memory.  However, the
     * pending-events list could be large, and so it's useful to discard it as
     * soon as possible --- especially if we are aborting because we ran out
     * of memory for the list!
     */
    if (afterTriggers.event_cxt)
    {
        MemoryContextDelete(afterTriggers.event_cxt);
        afterTriggers.event_cxt = NULL;
        afterTriggers.events.head = NULL;
        afterTriggers.events.tail = NULL;
        afterTriggers.events.tailfree = NULL;
    }
 
    /*
     * Forget any subtransaction state as well.  Since this can't be very
     * large, we let the eventual reset of TopTransactionContext free the
     * memory instead of doing it here.
     */
    afterTriggers.trans_stack = NULL;
    afterTriggers.maxtransdepth = 0;
 
 
    /*
     * Forget the query stack and constraint-related state information.  As
     * with the subtransaction state information, we don't bother freeing the
     * memory here.
     */
    afterTriggers.query_stack = NULL;
    afterTriggers.maxquerydepth = 0;
    afterTriggers.state = NULL;
 
    /* No more afterTriggers manipulation until next transaction starts. */
    afterTriggers.query_depth = -1;
}
 
/*
 * AfterTriggerBeginSubXact()
 *
 *  Start a subtransaction.
 */
void
AfterTriggerBeginSubXact(void)
{
    int         my_level = GetCurrentTransactionNestLevel();
 
    /*
     * Allocate more space in the trans_stack if needed.  (Note: because the
     * minimum nest level of a subtransaction is 2, we waste the first couple
     * entries of the array; not worth the notational effort to avoid it.)
     */
    while (my_level >= afterTriggers.maxtransdepth)
    {
        if (afterTriggers.maxtransdepth == 0)
        {
            /* Arbitrarily initialize for max of 8 subtransaction levels */
            afterTriggers.trans_stack = (AfterTriggersTransData *)
                MemoryContextAlloc(TopTransactionContext,
                                   8 * sizeof(AfterTriggersTransData));
            afterTriggers.maxtransdepth = 8;
        }
        else
        {
            /* repalloc will keep the stack in the same context */
            int         new_alloc = afterTriggers.maxtransdepth * 2;
 
            afterTriggers.trans_stack = (AfterTriggersTransData *)
                repalloc(afterTriggers.trans_stack,
                         new_alloc * sizeof(AfterTriggersTransData));
            afterTriggers.maxtransdepth = new_alloc;
        }
    }
 
    /*
     * Push the current information into the stack.  The SET CONSTRAINTS state
     * is not saved until/unless changed.  Likewise, we don't make a
     * per-subtransaction event context until needed.
     */
    afterTriggers.trans_stack[my_level].state = NULL;
    afterTriggers.trans_stack[my_level].events = afterTriggers.events;
    afterTriggers.trans_stack[my_level].query_depth = afterTriggers.query_depth;
    afterTriggers.trans_stack[my_level].firing_counter = afterTriggers.firing_counter;
}
 
/*
 * AfterTriggerEndSubXact()
 *
 *  The current subtransaction is ending.
 */
void
AfterTriggerEndSubXact(bool isCommit)
{
    int         my_level = GetCurrentTransactionNestLevel();
    SetConstraintState state;
    AfterTriggerEvent event;
    AfterTriggerEventChunk *chunk;
    CommandId   subxact_firing_id;
 
    /*
     * Pop the prior state if needed.
     */
    if (isCommit)
    {
        Assert(my_level < afterTriggers.maxtransdepth);
        /* If we saved a prior state, we don't need it anymore */
        state = afterTriggers.trans_stack[my_level].state;
        if (state != NULL)
            pfree(state);
        /* this avoids double pfree if error later: */
        afterTriggers.trans_stack[my_level].state = NULL;
        Assert(afterTriggers.query_depth ==
               afterTriggers.trans_stack[my_level].query_depth);
    }
    else
    {
        /*
         * Aborting.  It is possible subxact start failed before calling
         * AfterTriggerBeginSubXact, in which case we mustn't risk touching
         * trans_stack levels that aren't there.
         */
        if (my_level >= afterTriggers.maxtransdepth)
            return;
 
        /*
         * Release query-level storage for queries being aborted, and restore
         * query_depth to its pre-subxact value.  This assumes that a
         * subtransaction will not add events to query levels started in a
         * earlier transaction state.
         */
        while (afterTriggers.query_depth > afterTriggers.trans_stack[my_level].query_depth)
        {
            if (afterTriggers.query_depth < afterTriggers.maxquerydepth)
                AfterTriggerFreeQuery(&afterTriggers.query_stack[afterTriggers.query_depth]);
            afterTriggers.query_depth--;
        }
        Assert(afterTriggers.query_depth ==
               afterTriggers.trans_stack[my_level].query_depth);
 
        /*
         * Restore the global deferred-event list to its former length,
         * discarding any events queued by the subxact.
         */
        afterTriggerRestoreEventList(&afterTriggers.events,
                                     &afterTriggers.trans_stack[my_level].events);
 
        /*
         * Restore the trigger state.  If the saved state is NULL, then this
         * subxact didn't save it, so it doesn't need restoring.
         */
        state = afterTriggers.trans_stack[my_level].state;
        if (state != NULL)
        {
            pfree(afterTriggers.state);
            afterTriggers.state = state;
        }
        /* this avoids double pfree if error later: */
        afterTriggers.trans_stack[my_level].state = NULL;
 
        /*
         * Scan for any remaining deferred events that were marked DONE or IN
         * PROGRESS by this subxact or a child, and un-mark them. We can
         * recognize such events because they have a firing ID greater than or
         * equal to the firing_counter value we saved at subtransaction start.
         * (This essentially assumes that the current subxact includes all
         * subxacts started after it.)
         */
        subxact_firing_id = afterTriggers.trans_stack[my_level].firing_counter;
        for_each_event_chunk(event, chunk, afterTriggers.events)
        {
            AfterTriggerShared evtshared = GetTriggerSharedData(event);
 
            if (event->ate_flags &
                (AFTER_TRIGGER_DONE | AFTER_TRIGGER_IN_PROGRESS))
            {
                if (evtshared->ats_firing_id >= subxact_firing_id)
                    event->ate_flags &=
                        ~(AFTER_TRIGGER_DONE | AFTER_TRIGGER_IN_PROGRESS);
            }
        }
    }
}
 
/*
 * Get the transition table for the given event and depending on whether we are
 * processing the old or the new tuple.
 */
static Tuplestorestate *
GetAfterTriggersTransitionTable(int event,
                                TupleTableSlot *oldslot,
                                TupleTableSlot *newslot,
                                TransitionCaptureState *transition_capture)
{
    Tuplestorestate *tuplestore = NULL;
    bool        delete_old_table = transition_capture->tcs_delete_old_table;
    bool        update_old_table = transition_capture->tcs_update_old_table;
    bool        update_new_table = transition_capture->tcs_update_new_table;
    bool        insert_new_table = transition_capture->tcs_insert_new_table;
 
    /*
     * For INSERT events NEW should be non-NULL, for DELETE events OLD should
     * be non-NULL, whereas for UPDATE events normally both OLD and NEW are
     * non-NULL.  But for UPDATE events fired for capturing transition tuples
     * during UPDATE partition-key row movement, OLD is NULL when the event is
     * for a row being inserted, whereas NEW is NULL when the event is for a
     * row being deleted.
     */
    Assert(!(event == TRIGGER_EVENT_DELETE && delete_old_table &&
             TupIsNull(oldslot)));
    Assert(!(event == TRIGGER_EVENT_INSERT && insert_new_table &&
             TupIsNull(newslot)));
 
    if (!TupIsNull(oldslot))
    {
        Assert(TupIsNull(newslot));
        if (event == TRIGGER_EVENT_DELETE && delete_old_table)
            tuplestore = transition_capture->tcs_delete_private->old_tuplestore;
        else if (event == TRIGGER_EVENT_UPDATE && update_old_table)
            tuplestore = transition_capture->tcs_update_private->old_tuplestore;
    }
    else if (!TupIsNull(newslot))
    {
        Assert(TupIsNull(oldslot));
        if (event == TRIGGER_EVENT_INSERT && insert_new_table)
            tuplestore = transition_capture->tcs_insert_private->new_tuplestore;
        else if (event == TRIGGER_EVENT_UPDATE && update_new_table)
            tuplestore = transition_capture->tcs_update_private->new_tuplestore;
    }
 
    return tuplestore;
}
 
/*
 * Add the given heap tuple to the given tuplestore, applying the conversion
 * map if necessary.
 *
 * If original_insert_tuple is given, we can add that tuple without conversion.
 */
static void
TransitionTableAddTuple(EState *estate,
                        int event,
                        TransitionCaptureState *transition_capture,
                        ResultRelInfo *relinfo,
                        TupleTableSlot *slot,
                        TupleTableSlot *original_insert_tuple,
                        Tuplestorestate *tuplestore)
{
    TupleConversionMap *map;
 
    /*
     * Nothing needs to be done if we don't have a tuplestore.
     */
    if (tuplestore == NULL)
        return;
 
    if (original_insert_tuple)
        tuplestore_puttupleslot(tuplestore, original_insert_tuple);
    else if ((map = ExecGetChildToRootMap(relinfo)) != NULL)
    {
        AfterTriggersTableData *table;
        TupleTableSlot *storeslot;
 
        switch (event)
        {
            case TRIGGER_EVENT_INSERT:
                table = transition_capture->tcs_insert_private;
                break;
            case TRIGGER_EVENT_UPDATE:
                table = transition_capture->tcs_update_private;
                break;
            case TRIGGER_EVENT_DELETE:
                table = transition_capture->tcs_delete_private;
                break;
            default:
                elog(ERROR, "invalid after-trigger event code: %d", event);
                table = NULL;   /* keep compiler quiet */
                break;
        }
 
        storeslot = GetAfterTriggersStoreSlot(table, map->outdesc);
        execute_attr_map_slot(map->attrMap, slot, storeslot);
        tuplestore_puttupleslot(tuplestore, storeslot);
    }
    else
        tuplestore_puttupleslot(tuplestore, slot);
}
 
/* ----------
 * AfterTriggerEnlargeQueryState()
 *
 *  Prepare the necessary state so that we can record AFTER trigger events
 *  queued by a query.  It is allowed to have nested queries within a
 *  (sub)transaction, so we need to have separate state for each query
 *  nesting level.
 * ----------
 */
static void
AfterTriggerEnlargeQueryState(void)
{
    int         init_depth = afterTriggers.maxquerydepth;
 
    Assert(afterTriggers.query_depth >= afterTriggers.maxquerydepth);
 
    if (afterTriggers.maxquerydepth == 0)
    {
        int         new_alloc = Max(afterTriggers.query_depth + 1, 8);
 
        afterTriggers.query_stack = (AfterTriggersQueryData *)
            MemoryContextAlloc(TopTransactionContext,
                               new_alloc * sizeof(AfterTriggersQueryData));
        afterTriggers.maxquerydepth = new_alloc;
    }
    else
    {
        /* repalloc will keep the stack in the same context */
        int         old_alloc = afterTriggers.maxquerydepth;
        int         new_alloc = Max(afterTriggers.query_depth + 1,
                                    old_alloc * 2);
 
        afterTriggers.query_stack = (AfterTriggersQueryData *)
            repalloc(afterTriggers.query_stack,
                     new_alloc * sizeof(AfterTriggersQueryData));
        afterTriggers.maxquerydepth = new_alloc;
    }
 
    /* Initialize new array entries to empty */
    while (init_depth < afterTriggers.maxquerydepth)
    {
        AfterTriggersQueryData *qs = &afterTriggers.query_stack[init_depth];
 
        qs->events.head = NULL;
        qs->events.tail = NULL;
        qs->events.tailfree = NULL;
        qs->fdw_tuplestore = NULL;
        qs->tables = NIL;
 
        ++init_depth;
    }
}
 
/*
 * Create an empty SetConstraintState with room for numalloc trigstates
 */
static SetConstraintState
SetConstraintStateCreate(int numalloc)
{
    SetConstraintState state;
 
    /* Behave sanely with numalloc == 0 */
    if (numalloc <= 0)
        numalloc = 1;
 
    /*
     * We assume that zeroing will correctly initialize the state values.
     */
    state = (SetConstraintState)
        MemoryContextAllocZero(TopTransactionContext,
                               offsetof(SetConstraintStateData, trigstates) +
                               numalloc * sizeof(SetConstraintTriggerData));
 
    state->numalloc = numalloc;
 
    return state;
}
 
/*
 * Copy a SetConstraintState
 */
static SetConstraintState
SetConstraintStateCopy(SetConstraintState origstate)
{
    SetConstraintState state;
 
    state = SetConstraintStateCreate(origstate->numstates);
 
    state->all_isset = origstate->all_isset;
    state->all_isdeferred = origstate->all_isdeferred;
    state->numstates = origstate->numstates;
    memcpy(state->trigstates, origstate->trigstates,
           origstate->numstates * sizeof(SetConstraintTriggerData));
 
    return state;
}
 
/*
 * Add a per-trigger item to a SetConstraintState.  Returns possibly-changed
 * pointer to the state object (it will change if we have to repalloc).
 */
static SetConstraintState
SetConstraintStateAddItem(SetConstraintState state,
                          Oid tgoid, bool tgisdeferred)
{
    if (state->numstates >= state->numalloc)
    {
        int         newalloc = state->numalloc * 2;
 
        newalloc = Max(newalloc, 8);    /* in case original has size 0 */
        state = (SetConstraintState)
            repalloc(state,
                     offsetof(SetConstraintStateData, trigstates) +
                     newalloc * sizeof(SetConstraintTriggerData));
        state->numalloc = newalloc;
        Assert(state->numstates < state->numalloc);
    }
 
    state->trigstates[state->numstates].sct_tgoid = tgoid;
    state->trigstates[state->numstates].sct_tgisdeferred = tgisdeferred;
    state->numstates++;
 
    return state;
}
 
/* ----------
 * AfterTriggerSetState()
 *
 *  Execute the SET CONSTRAINTS ... utility command.
 * ----------
 */
void
AfterTriggerSetState(ConstraintsSetStmt *stmt)
{
    int         my_level = GetCurrentTransactionNestLevel();
 
    /* If we haven't already done so, initialize our state. */
    if (afterTriggers.state == NULL)
        afterTriggers.state = SetConstraintStateCreate(8);
 
    /*
     * If in a subtransaction, and we didn't save the current state already,
     * save it so it can be restored if the subtransaction aborts.
     */
    if (my_level > 1 &&
        afterTriggers.trans_stack[my_level].state == NULL)
    {
        afterTriggers.trans_stack[my_level].state =
            SetConstraintStateCopy(afterTriggers.state);
    }
 
    /*
     * Handle SET CONSTRAINTS ALL ...
     */
    if (stmt->constraints == NIL)
    {
        /*
         * Forget any previous SET CONSTRAINTS commands in this transaction.
         */
        afterTriggers.state->numstates = 0;
 
        /*
         * Set the per-transaction ALL state to known.
         */
        afterTriggers.state->all_isset = true;
        afterTriggers.state->all_isdeferred = stmt->deferred;
    }
    else
    {
        Relation    conrel;
        Relation    tgrel;
        List       *conoidlist = NIL;
        List       *tgoidlist = NIL;
        ListCell   *lc;
 
        /*
         * Handle SET CONSTRAINTS constraint-name [, ...]
         *
         * First, identify all the named constraints and make a list of their
         * OIDs.  Since, unlike the SQL spec, we allow multiple constraints of
         * the same name within a schema, the specifications are not
         * necessarily unique.  Our strategy is to target all matching
         * constraints within the first search-path schema that has any
         * matches, but disregard matches in schemas beyond the first match.
         * (This is a bit odd but it's the historical behavior.)
         *
         * A constraint in a partitioned table may have corresponding
         * constraints in the partitions.  Grab those too.
         */
        conrel = table_open(ConstraintRelationId, AccessShareLock);
 
        foreach(lc, stmt->constraints)
        {
            RangeVar   *constraint = lfirst(lc);
            bool        found;
            List       *namespacelist;
            ListCell   *nslc;
 
            if (constraint->catalogname)
            {
                if (strcmp(constraint->catalogname, get_database_name(MyDatabaseId)) != 0)
                    ereport(ERROR,
                            (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
                             errmsg("cross-database references are not implemented: \"%s.%s.%s\"",
                                    constraint->catalogname, constraint->schemaname,
                                    constraint->relname)));
            }
 
            /*
             * If we're given the schema name with the constraint, look only
             * in that schema.  If given a bare constraint name, use the
             * search path to find the first matching constraint.
             */
            if (constraint->schemaname)
            {
                Oid         namespaceId = LookupExplicitNamespace(constraint->schemaname,
                                                                  false);
 
                namespacelist = list_make1_oid(namespaceId);
            }
            else
            {
                namespacelist = fetch_search_path(true);
            }
 
            found = false;
            foreach(nslc, namespacelist)
            {
                Oid         namespaceId = lfirst_oid(nslc);
                SysScanDesc conscan;
                ScanKeyData skey[2];
                HeapTuple   tup;
 
                ScanKeyInit(&skey[0],
                            Anum_pg_constraint_conname,
                            BTEqualStrategyNumber, F_NAMEEQ,
                            CStringGetDatum(constraint->relname));
                ScanKeyInit(&skey[1],
                            Anum_pg_constraint_connamespace,
                            BTEqualStrategyNumber, F_OIDEQ,
                            ObjectIdGetDatum(namespaceId));
 
                conscan = systable_beginscan(conrel, ConstraintNameNspIndexId,
                                             true, NULL, 2, skey);
 
                while (HeapTupleIsValid(tup = systable_getnext(conscan)))
                {
                    Form_pg_constraint con = (Form_pg_constraint) GETSTRUCT(tup);
 
                    if (con->condeferrable)
                        conoidlist = lappend_oid(conoidlist, con->oid);
                    else if (stmt->deferred)
                        ereport(ERROR,
                                (errcode(ERRCODE_WRONG_OBJECT_TYPE),
                                 errmsg("constraint \"%s\" is not deferrable",
                                        constraint->relname)));
                    found = true;
                }
 
                systable_endscan(conscan);
 
                /*
                 * Once we've found a matching constraint we do not search
                 * later parts of the search path.
                 */
                if (found)
                    break;
            }
 
            list_free(namespacelist);
 
            /*
             * Not found ?
             */
            if (!found)
                ereport(ERROR,
                        (errcode(ERRCODE_UNDEFINED_OBJECT),
                         errmsg("constraint \"%s\" does not exist",
                                constraint->relname)));
        }
 
        /*
         * Scan for any possible descendants of the constraints.  We append
         * whatever we find to the same list that we're scanning; this has the
         * effect that we create new scans for those, too, so if there are
         * further descendents, we'll also catch them.
         */
        foreach(lc, conoidlist)
        {
            Oid         parent = lfirst_oid(lc);
            ScanKeyData key;
            SysScanDesc scan;
            HeapTuple   tuple;
 
            ScanKeyInit(&key,
                        Anum_pg_constraint_conparentid,
                        BTEqualStrategyNumber, F_OIDEQ,
                        ObjectIdGetDatum(parent));
 
            scan = systable_beginscan(conrel, ConstraintParentIndexId, true, NULL, 1, &key);
 
            while (HeapTupleIsValid(tuple = systable_getnext(scan)))
            {
                Form_pg_constraint con = (Form_pg_constraint) GETSTRUCT(tuple);
 
                conoidlist = lappend_oid(conoidlist, con->oid);
            }
 
            systable_endscan(scan);
        }
 
        table_close(conrel, AccessShareLock);
 
        /*
         * Now, locate the trigger(s) implementing each of these constraints,
         * and make a list of their OIDs.
         */
        tgrel = table_open(TriggerRelationId, AccessShareLock);
 
        foreach(lc, conoidlist)
        {
            Oid         conoid = lfirst_oid(lc);
            ScanKeyData skey;
            SysScanDesc tgscan;
            HeapTuple   htup;
 
            ScanKeyInit(&skey,
                        Anum_pg_trigger_tgconstraint,
                        BTEqualStrategyNumber, F_OIDEQ,
                        ObjectIdGetDatum(conoid));
 
            tgscan = systable_beginscan(tgrel, TriggerConstraintIndexId, true,
                                        NULL, 1, &skey);
 
            while (HeapTupleIsValid(htup = systable_getnext(tgscan)))
            {
                Form_pg_trigger pg_trigger = (Form_pg_trigger) GETSTRUCT(htup);
 
                /*
                 * Silently skip triggers that are marked as non-deferrable in
                 * pg_trigger.  This is not an error condition, since a
                 * deferrable RI constraint may have some non-deferrable
                 * actions.
                 */
                if (pg_trigger->tgdeferrable)
                    tgoidlist = lappend_oid(tgoidlist, pg_trigger->oid);
            }
 
            systable_endscan(tgscan);
        }
 
        table_close(tgrel, AccessShareLock);
 
        /*
         * Now we can set the trigger states of individual triggers for this
         * xact.
         */
        foreach(lc, tgoidlist)
        {
            Oid         tgoid = lfirst_oid(lc);
            SetConstraintState state = afterTriggers.state;
            bool        found = false;
            int         i;
 
            for (i = 0; i < state->numstates; i++)
            {
                if (state->trigstates[i].sct_tgoid == tgoid)
                {
                    state->trigstates[i].sct_tgisdeferred = stmt->deferred;
                    found = true;
                    break;
                }
            }
            if (!found)
            {
                afterTriggers.state =
                    SetConstraintStateAddItem(state, tgoid, stmt->deferred);
            }
        }
    }
 
    /*
     * SQL99 requires that when a constraint is set to IMMEDIATE, any deferred
     * checks against that constraint must be made when the SET CONSTRAINTS
     * command is executed -- i.e. the effects of the SET CONSTRAINTS command
     * apply retroactively.  We've updated the constraints state, so scan the
     * list of previously deferred events to fire any that have now become
     * immediate.
     *
     * Obviously, if this was SET ... DEFERRED then it can't have converted
     * any unfired events to immediate, so we need do nothing in that case.
     */
    if (!stmt->deferred)
    {
        AfterTriggerEventList *events = &afterTriggers.events;
        bool        snapshot_set = false;
 
        while (afterTriggerMarkEvents(events, NULL, true))
        {
            CommandId   firing_id = afterTriggers.firing_counter++;
 
            /*
             * Make sure a snapshot has been established in case trigger
             * functions need one.  Note that we avoid setting a snapshot if
             * we don't find at least one trigger that has to be fired now.
             * This is so that BEGIN; SET CONSTRAINTS ...; SET TRANSACTION
             * ISOLATION LEVEL SERIALIZABLE; ... works properly.  (If we are
             * at the start of a transaction it's not possible for any trigger
             * events to be queued yet.)
             */
            if (!snapshot_set)
            {
                PushActiveSnapshot(GetTransactionSnapshot());
                snapshot_set = true;
            }
 
            /*
             * We can delete fired events if we are at top transaction level,
             * but we'd better not if inside a subtransaction, since the
             * subtransaction could later get rolled back.
             */
            if (afterTriggerInvokeEvents(events, firing_id, NULL,
                                         !IsSubTransaction()))
                break;          /* all fired */
        }
 
        if (snapshot_set)
            PopActiveSnapshot();
    }
}
 
/* ----------
 * AfterTriggerPendingOnRel()
 *      Test to see if there are any pending after-trigger events for rel.
 *
 * This is used by TRUNCATE, CLUSTER, ALTER TABLE, etc to detect whether
 * it is unsafe to perform major surgery on a relation.  Note that only
 * local pending events are examined.  We assume that having exclusive lock
 * on a rel guarantees there are no unserviced events in other backends ---
 * but having a lock does not prevent there being such events in our own.
 *
 * In some scenarios it'd be reasonable to remove pending events (more
 * specifically, mark them DONE by the current subxact) but without a lot
 * of knowledge of the trigger semantics we can't do this in general.
 * ----------
 */
bool
AfterTriggerPendingOnRel(Oid relid)
{
    AfterTriggerEvent event;
    AfterTriggerEventChunk *chunk;
    int         depth;
 
    /* Scan queued events */
    for_each_event_chunk(event, chunk, afterTriggers.events)
    {
        AfterTriggerShared evtshared = GetTriggerSharedData(event);
 
        /*
         * We can ignore completed events.  (Even if a DONE flag is rolled
         * back by subxact abort, it's OK because the effects of the TRUNCATE
         * or whatever must get rolled back too.)
         */
        if (event->ate_flags & AFTER_TRIGGER_DONE)
            continue;
 
        if (evtshared->ats_relid == relid)
            return true;
    }
 
    /*
     * Also scan events queued by incomplete queries.  This could only matter
     * if TRUNCATE/etc is executed by a function or trigger within an updating
     * query on the same relation, which is pretty perverse, but let's check.
     */
    for (depth = 0; depth <= afterTriggers.query_depth && depth < afterTriggers.maxquerydepth; depth++)
    {
        for_each_event_chunk(event, chunk, afterTriggers.query_stack[depth].events)
        {
            AfterTriggerShared evtshared = GetTriggerSharedData(event);
 
            if (event->ate_flags & AFTER_TRIGGER_DONE)
                continue;
 
            if (evtshared->ats_relid == relid)
                return true;
        }
    }
 
    return false;
}
 
/* ----------
 * AfterTriggerSaveEvent()
 *
 *  Called by ExecA[RS]...Triggers() to queue up the triggers that should
 *  be fired for an event.
 *
 *  NOTE: this is called whenever there are any triggers associated with
 *  the event (even if they are disabled).  This function decides which
 *  triggers actually need to be queued.  It is also called after each row,
 *  even if there are no triggers for that event, if there are any AFTER
 *  STATEMENT triggers for the statement which use transition tables, so that
 *  the transition tuplestores can be built.  Furthermore, if the transition
 *  capture is happening for UPDATEd rows being moved to another partition due
 *  to the partition-key being changed, then this function is called once when
 *  the row is deleted (to capture OLD row), and once when the row is inserted
 *  into another partition (to capture NEW row).  This is done separately because
 *  DELETE and INSERT happen on different tables.
 *
 *  Transition tuplestores are built now, rather than when events are pulled
 *  off of the queue because AFTER ROW triggers are allowed to select from the
 *  transition tables for the statement.
 *
 *  This contains special support to queue the update events for the case where
 *  a partitioned table undergoing a cross-partition update may have foreign
 *  keys pointing into it.  Normally, a partitioned table's row triggers are
 *  not fired because the leaf partition(s) which are modified as a result of
 *  the operation on the partitioned table contain the same triggers which are
 *  fired instead. But that general scheme can cause problematic behavior with
 *  foreign key triggers during cross-partition updates, which are implemented
 *  as DELETE on the source partition followed by INSERT into the destination
 *  partition.  Specifically, firing DELETE triggers would lead to the wrong
 *  foreign key action to be enforced considering that the original command is
 *  UPDATE; in this case, this function is called with relinfo as the
 *  partitioned table, and src_partinfo and dst_partinfo referring to the
 *  source and target leaf partitions, respectively.
 *
 *  is_crosspart_update is true either when a DELETE event is fired on the
 *  source partition (which is to be ignored) or an UPDATE event is fired on
 *  the root partitioned table.
 * ----------
 */
static void
AfterTriggerSaveEvent(EState *estate, ResultRelInfo *relinfo,
                      ResultRelInfo *src_partinfo,
                      ResultRelInfo *dst_partinfo,
                      int event, bool row_trigger,
                      TupleTableSlot *oldslot, TupleTableSlot *newslot,
                      List *recheckIndexes, Bitmapset *modifiedCols,
                      TransitionCaptureState *transition_capture,
                      bool is_crosspart_update)
{
    Relation    rel = relinfo->ri_RelationDesc;
    TriggerDesc *trigdesc = relinfo->ri_TrigDesc;
    AfterTriggerEventData new_event;
    AfterTriggerSharedData new_shared;
    char        relkind = rel->rd_rel->relkind;
    int         tgtype_event;
    int         tgtype_level;
    int         i;
    Tuplestorestate *fdw_tuplestore = NULL;
 
    /*
     * Check state.  We use a normal test not Assert because it is possible to
     * reach here in the wrong state given misconfigured RI triggers, in
     * particular deferring a cascade action trigger.
     */
    if (afterTriggers.query_depth < 0)
        elog(ERROR, "AfterTriggerSaveEvent() called outside of query");
 
    /* Be sure we have enough space to record events at this query depth. */
    if (afterTriggers.query_depth >= afterTriggers.maxquerydepth)
        AfterTriggerEnlargeQueryState();
 
    /*
     * If the directly named relation has any triggers with transition tables,
     * then we need to capture transition tuples.
     */
    if (row_trigger && transition_capture != NULL)
    {
        TupleTableSlot *original_insert_tuple = transition_capture->tcs_original_insert_tuple;
 
        /*
         * Capture the old tuple in the appropriate transition table based on
         * the event.
         */
        if (!TupIsNull(oldslot))
        {
            Tuplestorestate *old_tuplestore;
 
            old_tuplestore = GetAfterTriggersTransitionTable(event,
                                                             oldslot,
                                                             NULL,
                                                             transition_capture);
            TransitionTableAddTuple(estate, event, transition_capture, relinfo,
                                    oldslot, NULL, old_tuplestore);
        }
 
        /*
         * Capture the new tuple in the appropriate transition table based on
         * the event.
         */
        if (!TupIsNull(newslot))
        {
            Tuplestorestate *new_tuplestore;
 
            new_tuplestore = GetAfterTriggersTransitionTable(event,
                                                             NULL,
                                                             newslot,
                                                             transition_capture);
            TransitionTableAddTuple(estate, event, transition_capture, relinfo,
                                    newslot, original_insert_tuple, new_tuplestore);
        }
 
        /*
         * If transition tables are the only reason we're here, return. As
         * mentioned above, we can also be here during update tuple routing in
         * presence of transition tables, in which case this function is
         * called separately for OLD and NEW, so we expect exactly one of them
         * to be NULL.
         */
        if (trigdesc == NULL ||
            (event == TRIGGER_EVENT_DELETE && !trigdesc->trig_delete_after_row) ||
            (event == TRIGGER_EVENT_INSERT && !trigdesc->trig_insert_after_row) ||
            (event == TRIGGER_EVENT_UPDATE && !trigdesc->trig_update_after_row) ||
            (event == TRIGGER_EVENT_UPDATE && (TupIsNull(oldslot) ^ TupIsNull(newslot))))
            return;
    }
 
    /*
     * We normally don't see partitioned tables here for row level triggers
     * except in the special case of a cross-partition update.  In that case,
     * nodeModifyTable.c:ExecCrossPartitionUpdateForeignKey() calls here to
     * queue an update event on the root target partitioned table, also
     * passing the source and destination partitions and their tuples.
     */
    Assert(!row_trigger ||
           rel->rd_rel->relkind != RELKIND_PARTITIONED_TABLE ||
           (is_crosspart_update &&
            TRIGGER_FIRED_BY_UPDATE(event) &&
            src_partinfo != NULL && dst_partinfo != NULL));
 
    /*
     * Validate the event code and collect the associated tuple CTIDs.
     *
     * The event code will be used both as a bitmask and an array offset, so
     * validation is important to make sure we don't walk off the edge of our
     * arrays.
     *
     * Also, if we're considering statement-level triggers, check whether we
     * already queued a set of them for this event, and cancel the prior set
     * if so.  This preserves the behavior that statement-level triggers fire
     * just once per statement and fire after row-level triggers.
     */
    switch (event)
    {
        case TRIGGER_EVENT_INSERT:
            tgtype_event = TRIGGER_TYPE_INSERT;
            if (row_trigger)
            {
                Assert(oldslot == NULL);
                Assert(newslot != NULL);
                ItemPointerCopy(&(newslot->tts_tid), &(new_event.ate_ctid1));
                ItemPointerSetInvalid(&(new_event.ate_ctid2));
            }
            else
            {
                Assert(oldslot == NULL);
                Assert(newslot == NULL);
                ItemPointerSetInvalid(&(new_event.ate_ctid1));
                ItemPointerSetInvalid(&(new_event.ate_ctid2));
                cancel_prior_stmt_triggers(RelationGetRelid(rel),
                                           CMD_INSERT, event);
            }
            break;
        case TRIGGER_EVENT_DELETE:
            tgtype_event = TRIGGER_TYPE_DELETE;
            if (row_trigger)
            {
                Assert(oldslot != NULL);
                Assert(newslot == NULL);
                ItemPointerCopy(&(oldslot->tts_tid), &(new_event.ate_ctid1));
                ItemPointerSetInvalid(&(new_event.ate_ctid2));
            }
            else
            {
                Assert(oldslot == NULL);
                Assert(newslot == NULL);
                ItemPointerSetInvalid(&(new_event.ate_ctid1));
                ItemPointerSetInvalid(&(new_event.ate_ctid2));
                cancel_prior_stmt_triggers(RelationGetRelid(rel),
                                           CMD_DELETE, event);
            }
            break;
        case TRIGGER_EVENT_UPDATE:
            tgtype_event = TRIGGER_TYPE_UPDATE;
            if (row_trigger)
            {
                Assert(oldslot != NULL);
                Assert(newslot != NULL);
                ItemPointerCopy(&(oldslot->tts_tid), &(new_event.ate_ctid1));
                ItemPointerCopy(&(newslot->tts_tid), &(new_event.ate_ctid2));
 
                /*
                 * Also remember the OIDs of partitions to fetch these tuples
                 * out of later in AfterTriggerExecute().
                 */
                if (rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
                {
                    Assert(src_partinfo != NULL && dst_partinfo != NULL);
                    new_event.ate_src_part =
                        RelationGetRelid(src_partinfo->ri_RelationDesc);
                    new_event.ate_dst_part =
                        RelationGetRelid(dst_partinfo->ri_RelationDesc);
                }
            }
            else
            {
                Assert(oldslot == NULL);
                Assert(newslot == NULL);
                ItemPointerSetInvalid(&(new_event.ate_ctid1));
                ItemPointerSetInvalid(&(new_event.ate_ctid2));
                cancel_prior_stmt_triggers(RelationGetRelid(rel),
                                           CMD_UPDATE, event);
            }
            break;
        case TRIGGER_EVENT_TRUNCATE:
            tgtype_event = TRIGGER_TYPE_TRUNCATE;
            Assert(oldslot == NULL);
            Assert(newslot == NULL);
            ItemPointerSetInvalid(&(new_event.ate_ctid1));
            ItemPointerSetInvalid(&(new_event.ate_ctid2));
            break;
        default:
            elog(ERROR, "invalid after-trigger event code: %d", event);
            tgtype_event = 0;   /* keep compiler quiet */
            break;
    }
 
    /* Determine flags */
    if (!(relkind == RELKIND_FOREIGN_TABLE && row_trigger))
    {
        if (row_trigger && event == TRIGGER_EVENT_UPDATE)
        {
            if (relkind == RELKIND_PARTITIONED_TABLE)
                new_event.ate_flags = AFTER_TRIGGER_CP_UPDATE;
            else
                new_event.ate_flags = AFTER_TRIGGER_2CTID;
        }
        else
            new_event.ate_flags = AFTER_TRIGGER_1CTID;
    }
 
    /* else, we'll initialize ate_flags for each trigger */
 
    tgtype_level = (row_trigger ? TRIGGER_TYPE_ROW : TRIGGER_TYPE_STATEMENT);
 
    /*
     * Must convert/copy the source and destination partition tuples into the
     * root partitioned table's format/slot, because the processing in the
     * loop below expects both oldslot and newslot tuples to be in that form.
     */
    if (row_trigger && rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
    {
        TupleTableSlot *rootslot;
        TupleConversionMap *map;
 
        rootslot = ExecGetTriggerOldSlot(estate, relinfo);
        map = ExecGetChildToRootMap(src_partinfo);
        if (map)
            oldslot = execute_attr_map_slot(map->attrMap,
                                            oldslot,
                                            rootslot);
        else
            oldslot = ExecCopySlot(rootslot, oldslot);
 
        rootslot = ExecGetTriggerNewSlot(estate, relinfo);
        map = ExecGetChildToRootMap(dst_partinfo);
        if (map)
            newslot = execute_attr_map_slot(map->attrMap,
                                            newslot,
                                            rootslot);
        else
            newslot = ExecCopySlot(rootslot, newslot);
    }
 
    for (i = 0; i < trigdesc->numtriggers; i++)
    {
        Trigger    *trigger = &trigdesc->triggers[i];
 
        if (!TRIGGER_TYPE_MATCHES(trigger->tgtype,
                                  tgtype_level,
                                  TRIGGER_TYPE_AFTER,
                                  tgtype_event))
            continue;
        if (!TriggerEnabled(estate, relinfo, trigger, event,
                            modifiedCols, oldslot, newslot))
            continue;
 
        if (relkind == RELKIND_FOREIGN_TABLE && row_trigger)
        {
            if (fdw_tuplestore == NULL)
            {
                fdw_tuplestore = GetCurrentFDWTuplestore();
                new_event.ate_flags = AFTER_TRIGGER_FDW_FETCH;
            }
            else
                /* subsequent event for the same tuple */
                new_event.ate_flags = AFTER_TRIGGER_FDW_REUSE;
        }
 
        /*
         * If the trigger is a foreign key enforcement trigger, there are
         * certain cases where we can skip queueing the event because we can
         * tell by inspection that the FK constraint will still pass. There
         * are also some cases during cross-partition updates of a partitioned
         * table where queuing the event can be skipped.
         */
        if (TRIGGER_FIRED_BY_UPDATE(event) || TRIGGER_FIRED_BY_DELETE(event))
        {
            switch (RI_FKey_trigger_type(trigger->tgfoid))
            {
                case RI_TRIGGER_PK:
 
                    /*
                     * For cross-partitioned updates of partitioned PK table,
                     * skip the event fired by the component delete on the
                     * source leaf partition unless the constraint originates
                     * in the partition itself (!tgisclone), because the
                     * update event that will be fired on the root
                     * (partitioned) target table will be used to perform the
                     * necessary foreign key enforcement action.
                     */
                    if (is_crosspart_update &&
                        TRIGGER_FIRED_BY_DELETE(event) &&
                        trigger->tgisclone)
                        continue;
 
                    /* Update or delete on trigger's PK table */
                    if (!RI_FKey_pk_upd_check_required(trigger, rel,
                                                       oldslot, newslot))
                    {
                        /* skip queuing this event */
                        continue;
                    }
                    break;
 
                case RI_TRIGGER_FK:
 
                    /*
                     * Update on trigger's FK table.  We can skip the update
                     * event fired on a partitioned table during a
                     * cross-partition of that table, because the insert event
                     * that is fired on the destination leaf partition would
                     * suffice to perform the necessary foreign key check.
                     * Moreover, RI_FKey_fk_upd_check_required() expects to be
                     * passed a tuple that contains system attributes, most of
                     * which are not present in the virtual slot belonging to
                     * a partitioned table.
                     */
                    if (rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE ||
                        !RI_FKey_fk_upd_check_required(trigger, rel,
                                                       oldslot, newslot))
                    {
                        /* skip queuing this event */
                        continue;
                    }
                    break;
 
                case RI_TRIGGER_NONE:
 
                    /*
                     * Not an FK trigger.  No need to queue the update event
                     * fired during a cross-partitioned update of a
                     * partitioned table, because the same row trigger must be
                     * present in the leaf partition(s) that are affected as
                     * part of this update and the events fired on them are
                     * queued instead.
                     */
                    if (row_trigger &&
                        rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
                        continue;
                    break;
            }
        }
 
        /*
         * If the trigger is a deferred unique constraint check trigger, only
         * queue it if the unique constraint was potentially violated, which
         * we know from index insertion time.
         */
        if (trigger->tgfoid == F_UNIQUE_KEY_RECHECK)
        {
            if (!list_member_oid(recheckIndexes, trigger->tgconstrindid))
                continue;       /* Uniqueness definitely not violated */
        }
 
        /*
         * Fill in event structure and add it to the current query's queue.
         * Note we set ats_table to NULL whenever this trigger doesn't use
         * transition tables, to improve sharability of the shared event data.
         */
        new_shared.ats_event =
            (event & TRIGGER_EVENT_OPMASK) |
            (row_trigger ? TRIGGER_EVENT_ROW : 0) |
            (trigger->tgdeferrable ? AFTER_TRIGGER_DEFERRABLE : 0) |
            (trigger->tginitdeferred ? AFTER_TRIGGER_INITDEFERRED : 0);
        new_shared.ats_tgoid = trigger->tgoid;
        new_shared.ats_relid = RelationGetRelid(rel);
        new_shared.ats_rolid = GetUserId();
        new_shared.ats_firing_id = 0;
        if ((trigger->tgoldtable || trigger->tgnewtable) &&
            transition_capture != NULL)
        {
            switch (event)
            {
                case TRIGGER_EVENT_INSERT:
                    new_shared.ats_table = transition_capture->tcs_insert_private;
                    break;
                case TRIGGER_EVENT_UPDATE:
                    new_shared.ats_table = transition_capture->tcs_update_private;
                    break;
                case TRIGGER_EVENT_DELETE:
                    new_shared.ats_table = transition_capture->tcs_delete_private;
                    break;
                default:
                    /* Must be TRUNCATE, see switch above */
                    new_shared.ats_table = NULL;
                    break;
            }
        }
        else
            new_shared.ats_table = NULL;
        new_shared.ats_modifiedcols = modifiedCols;
 
        afterTriggerAddEvent(&afterTriggers.query_stack[afterTriggers.query_depth].events,
                             &new_event, &new_shared);
    }
 
    /*
     * Finally, spool any foreign tuple(s).  The tuplestore squashes them to
     * minimal tuples, so this loses any system columns.  The executor lost
     * those columns before us, for an unrelated reason, so this is fine.
     */
    if (fdw_tuplestore)
    {
        if (oldslot != NULL)
            tuplestore_puttupleslot(fdw_tuplestore, oldslot);
        if (newslot != NULL)
            tuplestore_puttupleslot(fdw_tuplestore, newslot);
    }
}
 
/*
 * Detect whether we already queued BEFORE STATEMENT triggers for the given
 * relation + operation, and set the flag so the next call will report "true".
 */
static bool
before_stmt_triggers_fired(Oid relid, CmdType cmdType)
{
    bool        result;
    AfterTriggersTableData *table;
 
    /* Check state, like AfterTriggerSaveEvent. */
    if (afterTriggers.query_depth < 0)
        elog(ERROR, "before_stmt_triggers_fired() called outside of query");
 
    /* Be sure we have enough space to record events at this query depth. */
    if (afterTriggers.query_depth >= afterTriggers.maxquerydepth)
        AfterTriggerEnlargeQueryState();
 
    /*
     * We keep this state in the AfterTriggersTableData that also holds
     * transition tables for the relation + operation.  In this way, if we are
     * forced to make a new set of transition tables because more tuples get
     * entered after we've already fired triggers, we will allow a new set of
     * statement triggers to get queued.
     */
    table = GetAfterTriggersTableData(relid, cmdType);
    result = table->before_trig_done;
    table->before_trig_done = true;
    return result;
}
 
/*
 * If we previously queued a set of AFTER STATEMENT triggers for the given
 * relation + operation, and they've not been fired yet, cancel them.  The
 * caller will queue a fresh set that's after any row-level triggers that may
 * have been queued by the current sub-statement, preserving (as much as
 * possible) the property that AFTER ROW triggers fire before AFTER STATEMENT
 * triggers, and that the latter only fire once.  This deals with the
 * situation where several FK enforcement triggers sequentially queue triggers
 * for the same table into the same trigger query level.  We can't fully
 * prevent odd behavior though: if there are AFTER ROW triggers taking
 * transition tables, we don't want to change the transition tables once the
 * first such trigger has seen them.  In such a case, any additional events
 * will result in creating new transition tables and allowing new firings of
 * statement triggers.
 *
 * This also saves the current event list location so that a later invocation
 * of this function can cheaply find the triggers we're about to queue and
 * cancel them.
 */
static void
cancel_prior_stmt_triggers(Oid relid, CmdType cmdType, int tgevent)
{
    AfterTriggersTableData *table;
    AfterTriggersQueryData *qs = &afterTriggers.query_stack[afterTriggers.query_depth];
 
    /*
     * We keep this state in the AfterTriggersTableData that also holds
     * transition tables for the relation + operation.  In this way, if we are
     * forced to make a new set of transition tables because more tuples get
     * entered after we've already fired triggers, we will allow a new set of
     * statement triggers to get queued without canceling the old ones.
     */
    table = GetAfterTriggersTableData(relid, cmdType);
 
    if (table->after_trig_done)
    {
        /*
         * We want to start scanning from the tail location that existed just
         * before we inserted any statement triggers.  But the events list
         * might've been entirely empty then, in which case scan from the
         * current head.
         */
        AfterTriggerEvent event;
        AfterTriggerEventChunk *chunk;
 
        if (table->after_trig_events.tail)
        {
            chunk = table->after_trig_events.tail;
            event = (AfterTriggerEvent) table->after_trig_events.tailfree;
        }
        else
        {
            chunk = qs->events.head;
            event = NULL;
        }
 
        for_each_chunk_from(chunk)
        {
            if (event == NULL)
                event = (AfterTriggerEvent) CHUNK_DATA_START(chunk);
            for_each_event_from(event, chunk)
            {
                AfterTriggerShared evtshared = GetTriggerSharedData(event);
 
                /*
                 * Exit loop when we reach events that aren't AS triggers for
                 * the target relation.
                 */
                if (evtshared->ats_relid != relid)
                    goto done;
                if ((evtshared->ats_event & TRIGGER_EVENT_OPMASK) != tgevent)
                    goto done;
                if (!TRIGGER_FIRED_FOR_STATEMENT(evtshared->ats_event))
                    goto done;
                if (!TRIGGER_FIRED_AFTER(evtshared->ats_event))
                    goto done;
                /* OK, mark it DONE */
                event->ate_flags &= ~AFTER_TRIGGER_IN_PROGRESS;
                event->ate_flags |= AFTER_TRIGGER_DONE;
            }
            /* signal we must reinitialize event ptr for next chunk */
            event = NULL;
        }
    }
done:
 
    /* In any case, save current insertion point for next time */
    table->after_trig_done = true;
    table->after_trig_events = qs->events;
}
 
/*
 * GUC assign_hook for session_replication_role
 */
void
assign_session_replication_role(int newval, void *extra)
{
    /*
     * Must flush the plan cache when changing replication role; but don't
     * flush unnecessarily.
     */
    if (SessionReplicationRole != newval)
        ResetPlanCache();
}
 
/*
 * SQL function pg_trigger_depth()
 */
Datum
pg_trigger_depth(PG_FUNCTION_ARGS)
{
    PG_RETURN_INT32(MyTriggerDepth);
}
 
/*
 * Check whether a trigger modified a virtual generated column and replace the
 * value with null if so.
 *
 * We need to check this so that we don't end up storing a non-null value in a
 * virtual generated column.
 *
 * We don't need to check for stored generated columns, since those will be
 * overwritten later anyway.
 */
static HeapTuple
check_modified_virtual_generated(TupleDesc tupdesc, HeapTuple tuple)
{
    if (!(tupdesc->constr && tupdesc->constr->has_generated_virtual))
        return tuple;
 
    for (int i = 0; i < tupdesc->natts; i++)
    {
        if (TupleDescAttr(tupdesc, i)->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
        {
            if (!heap_attisnull(tuple, i + 1, tupdesc))
            {
                int         replCol = i + 1;
                Datum       replValue = 0;
                bool        replIsnull = true;
 
                tuple = heap_modify_tuple_by_cols(tuple, tupdesc, 1, &replCol, &replValue, &replIsnull);
            }
        }
    }
 
    return tuple;
}