heap.c

Go to the documentation of this file.

/*-------------------------------------------------------------------------
 *
 * heap.c
 *    code to create and destroy POSTGRES heap relations
 *
 * Portions Copyright (c) 1996-2026, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 *
 * IDENTIFICATION
 *    src/backend/catalog/heap.c
 *
 *
 * INTERFACE ROUTINES
 *      heap_create()           - Create an uncataloged heap relation
 *      heap_create_with_catalog() - Create a cataloged relation
 *      heap_drop_with_catalog() - Removes named relation from catalogs
 *
 * NOTES
 *    this code taken from access/heap/create.c, which contains
 *    the old heap_create_with_catalog, amcreate, and amdestroy.
 *    those routines will soon call these routines using the function
 *    manager,
 *    just like the poorly named "NewXXX" routines do.  The
 *    "New" routines are all going to die soon, once and for all!
 *      -cim 1/13/91
 *
 *-------------------------------------------------------------------------
 */
#include "postgres.h"
 
#include "access/genam.h"
#include "access/multixact.h"
#include "access/relation.h"
#include "access/table.h"
#include "access/tableam.h"
#include "catalog/binary_upgrade.h"
#include "catalog/catalog.h"
#include "catalog/heap.h"
#include "catalog/index.h"
#include "catalog/objectaccess.h"
#include "catalog/partition.h"
#include "catalog/pg_am.h"
#include "catalog/pg_attrdef.h"
#include "catalog/pg_collation.h"
#include "catalog/pg_constraint.h"
#include "catalog/pg_foreign_table.h"
#include "catalog/pg_inherits.h"
#include "catalog/pg_namespace.h"
#include "catalog/pg_opclass.h"
#include "catalog/pg_partitioned_table.h"
#include "catalog/pg_statistic.h"
#include "catalog/pg_subscription_rel.h"
#include "catalog/pg_tablespace.h"
#include "catalog/pg_type.h"
#include "catalog/storage.h"
#include "commands/tablecmds.h"
#include "commands/typecmds.h"
#include "common/int.h"
#include "miscadmin.h"
#include "nodes/nodeFuncs.h"
#include "optimizer/optimizer.h"
#include "parser/parse_coerce.h"
#include "parser/parse_collate.h"
#include "parser/parse_expr.h"
#include "parser/parse_relation.h"
#include "parser/parsetree.h"
#include "partitioning/partdesc.h"
#include "pgstat.h"
#include "storage/lmgr.h"
#include "storage/predicate.h"
#include "utils/array.h"
#include "utils/builtins.h"
#include "utils/fmgroids.h"
#include "utils/inval.h"
#include "utils/lsyscache.h"
#include "utils/syscache.h"
 
 
/* Potentially set by pg_upgrade_support functions */
Oid         binary_upgrade_next_heap_pg_class_oid = InvalidOid;
Oid         binary_upgrade_next_toast_pg_class_oid = InvalidOid;
RelFileNumber binary_upgrade_next_heap_pg_class_relfilenumber = InvalidRelFileNumber;
RelFileNumber binary_upgrade_next_toast_pg_class_relfilenumber = InvalidRelFileNumber;
 
static void AddNewRelationTuple(Relation pg_class_desc,
                                Relation new_rel_desc,
                                Oid new_rel_oid,
                                Oid new_type_oid,
                                Oid reloftype,
                                Oid relowner,
                                char relkind,
                                TransactionId relfrozenxid,
                                TransactionId relminmxid,
                                Datum relacl,
                                Datum reloptions);
static ObjectAddress AddNewRelationType(const char *typeName,
                                        Oid typeNamespace,
                                        Oid new_rel_oid,
                                        char new_rel_kind,
                                        Oid ownerid,
                                        Oid new_row_type,
                                        Oid new_array_type);
static void RelationRemoveInheritance(Oid relid);
static Oid  StoreRelCheck(Relation rel, const char *ccname, Node *expr,
                          bool is_enforced, bool is_validated, bool is_local,
                          int16 inhcount, bool is_no_inherit, bool is_internal);
static void StoreConstraints(Relation rel, List *cooked_constraints,
                             bool is_internal);
static bool MergeWithExistingConstraint(Relation rel, const char *ccname, Node *expr,
                                        bool allow_merge, bool is_local,
                                        bool is_enforced,
                                        bool is_initially_valid,
                                        bool is_no_inherit);
static void SetRelationNumChecks(Relation rel, int numchecks);
static Node *cookConstraint(ParseState *pstate,
                            Node *raw_constraint,
                            char *relname);
 
 
/* ----------------------------------------------------------------
 *              XXX UGLY HARD CODED BADNESS FOLLOWS XXX
 *
 *      these should all be moved to someplace in the lib/catalog
 *      module, if not obliterated first.
 * ----------------------------------------------------------------
 */
 
 
/*
 * Note:
 *      Should the system special case these attributes in the future?
 *      Advantage:  consume much less space in the ATTRIBUTE relation.
 *      Disadvantage:  special cases will be all over the place.
 */
 
/*
 * The initializers below do not include trailing variable length fields,
 * but that's OK - we're never going to reference anything beyond the
 * fixed-size portion of the structure anyway.  Fields that can default
 * to zeroes are also not mentioned.
 */
 
static const FormData_pg_attribute a1 = {
    .attname = {"ctid"},
    .atttypid = TIDOID,
    .attlen = sizeof(ItemPointerData),
    .attnum = SelfItemPointerAttributeNumber,
    .atttypmod = -1,
    .attbyval = false,
    .attalign = TYPALIGN_SHORT,
    .attstorage = TYPSTORAGE_PLAIN,
    .attnotnull = true,
    .attislocal = true,
};
 
static const FormData_pg_attribute a2 = {
    .attname = {"xmin"},
    .atttypid = XIDOID,
    .attlen = sizeof(TransactionId),
    .attnum = MinTransactionIdAttributeNumber,
    .atttypmod = -1,
    .attbyval = true,
    .attalign = TYPALIGN_INT,
    .attstorage = TYPSTORAGE_PLAIN,
    .attnotnull = true,
    .attislocal = true,
};
 
static const FormData_pg_attribute a3 = {
    .attname = {"cmin"},
    .atttypid = CIDOID,
    .attlen = sizeof(CommandId),
    .attnum = MinCommandIdAttributeNumber,
    .atttypmod = -1,
    .attbyval = true,
    .attalign = TYPALIGN_INT,
    .attstorage = TYPSTORAGE_PLAIN,
    .attnotnull = true,
    .attislocal = true,
};
 
static const FormData_pg_attribute a4 = {
    .attname = {"xmax"},
    .atttypid = XIDOID,
    .attlen = sizeof(TransactionId),
    .attnum = MaxTransactionIdAttributeNumber,
    .atttypmod = -1,
    .attbyval = true,
    .attalign = TYPALIGN_INT,
    .attstorage = TYPSTORAGE_PLAIN,
    .attnotnull = true,
    .attislocal = true,
};
 
static const FormData_pg_attribute a5 = {
    .attname = {"cmax"},
    .atttypid = CIDOID,
    .attlen = sizeof(CommandId),
    .attnum = MaxCommandIdAttributeNumber,
    .atttypmod = -1,
    .attbyval = true,
    .attalign = TYPALIGN_INT,
    .attstorage = TYPSTORAGE_PLAIN,
    .attnotnull = true,
    .attislocal = true,
};
 
/*
 * We decided to call this attribute "tableoid" rather than say
 * "classoid" on the basis that in the future there may be more than one
 * table of a particular class/type. In any case table is still the word
 * used in SQL.
 */
static const FormData_pg_attribute a6 = {
    .attname = {"tableoid"},
    .atttypid = OIDOID,
    .attlen = sizeof(Oid),
    .attnum = TableOidAttributeNumber,
    .atttypmod = -1,
    .attbyval = true,
    .attalign = TYPALIGN_INT,
    .attstorage = TYPSTORAGE_PLAIN,
    .attnotnull = true,
    .attislocal = true,
};
 
static const FormData_pg_attribute *const SysAtt[] = {&a1, &a2, &a3, &a4, &a5, &a6};
 
/*
 * This function returns a Form_pg_attribute pointer for a system attribute.
 * Note that we elog if the presented attno is invalid, which would only
 * happen if there's a problem upstream.
 */
const FormData_pg_attribute *
SystemAttributeDefinition(AttrNumber attno)
{
    if (attno >= 0 || attno < -(int) lengthof(SysAtt))
        elog(ERROR, "invalid system attribute number %d", attno);
    return SysAtt[-attno - 1];
}
 
/*
 * If the given name is a system attribute name, return a Form_pg_attribute
 * pointer for a prototype definition.  If not, return NULL.
 */
const FormData_pg_attribute *
SystemAttributeByName(const char *attname)
{
    int         j;
 
    for (j = 0; j < (int) lengthof(SysAtt); j++)
    {
        const FormData_pg_attribute *att = SysAtt[j];
 
        if (strcmp(NameStr(att->attname), attname) == 0)
            return att;
    }
 
    return NULL;
}
 
 
/* ----------------------------------------------------------------
 *              XXX END OF UGLY HARD CODED BADNESS XXX
 * ----------------------------------------------------------------
 */
 
 
/* ----------------------------------------------------------------
 *      heap_create     - Create an uncataloged heap relation
 *
 *      Note API change: the caller must now always provide the OID
 *      to use for the relation.  The relfilenumber may be (and in
 *      the simplest cases is) left unspecified.
 *
 *      create_storage indicates whether or not to create the storage.
 *      However, even if create_storage is true, no storage will be
 *      created if the relkind is one that doesn't have storage.
 *
 *      rel->rd_rel is initialized by RelationBuildLocalRelation,
 *      and is mostly zeroes at return.
 * ----------------------------------------------------------------
 */
Relation
heap_create(const char *relname,
            Oid relnamespace,
            Oid reltablespace,
            Oid relid,
            RelFileNumber relfilenumber,
            Oid accessmtd,
            TupleDesc tupDesc,
            char relkind,
            char relpersistence,
            bool shared_relation,
            bool mapped_relation,
            bool allow_system_table_mods,
            TransactionId *relfrozenxid,
            MultiXactId *relminmxid,
            bool create_storage)
{
    Relation    rel;
 
    /* The caller must have provided an OID for the relation. */
    Assert(OidIsValid(relid));
 
    /*
     * Don't allow creating relations in pg_catalog directly, even though it
     * is allowed to move user defined relations there. Semantics with search
     * paths including pg_catalog are too confusing for now.
     *
     * But allow creating indexes on relations in pg_catalog even if
     * allow_system_table_mods = off, upper layers already guarantee it's on a
     * user defined relation, not a system one.
     */
    if (!allow_system_table_mods &&
        ((IsCatalogNamespace(relnamespace) && relkind != RELKIND_INDEX) ||
         IsToastNamespace(relnamespace)) &&
        IsNormalProcessingMode())
        ereport(ERROR,
                (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
                 errmsg("permission denied to create \"%s.%s\"",
                        get_namespace_name(relnamespace), relname),
                 errdetail("System catalog modifications are currently disallowed.")));
 
    *relfrozenxid = InvalidTransactionId;
    *relminmxid = InvalidMultiXactId;
 
    /*
     * Force reltablespace to zero if the relation kind does not support
     * tablespaces.  This is mainly just for cleanliness' sake.
     */
    if (!RELKIND_HAS_TABLESPACE(relkind))
        reltablespace = InvalidOid;
 
    /* Don't create storage for relkinds without physical storage. */
    if (!RELKIND_HAS_STORAGE(relkind))
        create_storage = false;
    else
    {
        /*
         * If relfilenumber is unspecified by the caller then create storage
         * with oid same as relid.
         */
        if (!RelFileNumberIsValid(relfilenumber))
            relfilenumber = relid;
    }
 
    /*
     * Never allow a pg_class entry to explicitly specify the database's
     * default tablespace in reltablespace; force it to zero instead. This
     * ensures that if the database is cloned with a different default
     * tablespace, the pg_class entry will still match where CREATE DATABASE
     * will put the physically copied relation.
     *
     * Yes, this is a bit of a hack.
     */
    if (reltablespace == MyDatabaseTableSpace)
        reltablespace = InvalidOid;
 
    /*
     * build the relcache entry.
     */
    rel = RelationBuildLocalRelation(relname,
                                     relnamespace,
                                     tupDesc,
                                     relid,
                                     accessmtd,
                                     relfilenumber,
                                     reltablespace,
                                     shared_relation,
                                     mapped_relation,
                                     relpersistence,
                                     relkind);
 
    /*
     * Have the storage manager create the relation's disk file, if needed.
     *
     * For tables, the AM callback creates both the main and the init fork.
     * For others, only the main fork is created; the other forks will be
     * created on demand.
     */
    if (create_storage)
    {
        if (RELKIND_HAS_TABLE_AM(rel->rd_rel->relkind))
            table_relation_set_new_filelocator(rel, &rel->rd_locator,
                                               relpersistence,
                                               relfrozenxid, relminmxid);
        else if (RELKIND_HAS_STORAGE(rel->rd_rel->relkind))
            RelationCreateStorage(rel->rd_locator, relpersistence, true);
        else
            Assert(false);
    }
 
    /*
     * If a tablespace is specified, removal of that tablespace is normally
     * protected by the existence of a physical file; but for relations with
     * no files, add a pg_shdepend entry to account for that.
     */
    if (!create_storage && reltablespace != InvalidOid)
        recordDependencyOnTablespace(RelationRelationId, relid,
                                     reltablespace);
 
    /* ensure that stats are dropped if transaction aborts */
    pgstat_create_relation(rel);
 
    return rel;
}
 
/* ----------------------------------------------------------------
 *      heap_create_with_catalog        - Create a cataloged relation
 *
 *      this is done in multiple steps:
 *
 *      1) CheckAttributeNamesTypes() is used to make certain the tuple
 *         descriptor contains a valid set of attribute names and types
 *
 *      2) pg_class is opened and get_relname_relid()
 *         performs a scan to ensure that no relation with the
 *         same name already exists.
 *
 *      3) heap_create() is called to create the new relation on disk.
 *
 *      4) TypeCreate() is called to define a new type corresponding
 *         to the new relation.
 *
 *      5) AddNewRelationTuple() is called to register the
 *         relation in pg_class.
 *
 *      6) AddNewAttributeTuples() is called to register the
 *         new relation's schema in pg_attribute.
 *
 *      7) StoreConstraints() is called         - vadim 08/22/97
 *
 *      8) the relations are closed and the new relation's oid
 *         is returned.
 *
 * ----------------------------------------------------------------
 */
 
/* --------------------------------
 *      CheckAttributeNamesTypes
 *
 *      this is used to make certain the tuple descriptor contains a
 *      valid set of attribute names and datatypes.  a problem simply
 *      generates ereport(ERROR) which aborts the current transaction.
 *
 *      relkind is the relkind of the relation to be created.
 *      flags controls which datatypes are allowed, cf CheckAttributeType.
 * --------------------------------
 */
void
CheckAttributeNamesTypes(TupleDesc tupdesc, char relkind,
                         int flags)
{
    int         i;
    int         j;
    int         natts = tupdesc->natts;
 
    /* Sanity check on column count */
    if (natts < 0 || natts > MaxHeapAttributeNumber)
        ereport(ERROR,
                (errcode(ERRCODE_TOO_MANY_COLUMNS),
                 errmsg("tables can have at most %d columns",
                        MaxHeapAttributeNumber)));
 
    /*
     * first check for collision with system attribute names
     *
     * Skip this for a view or type relation, since those don't have system
     * attributes.
     */
    if (relkind != RELKIND_VIEW && relkind != RELKIND_COMPOSITE_TYPE)
    {
        for (i = 0; i < natts; i++)
        {
            Form_pg_attribute attr = TupleDescAttr(tupdesc, i);
 
            if (SystemAttributeByName(NameStr(attr->attname)) != NULL)
                ereport(ERROR,
                        (errcode(ERRCODE_DUPLICATE_COLUMN),
                         errmsg("column name \"%s\" conflicts with a system column name",
                                NameStr(attr->attname))));
        }
    }
 
    /*
     * next check for repeated attribute names
     */
    for (i = 1; i < natts; i++)
    {
        for (j = 0; j < i; j++)
        {
            if (strcmp(NameStr(TupleDescAttr(tupdesc, j)->attname),
                       NameStr(TupleDescAttr(tupdesc, i)->attname)) == 0)
                ereport(ERROR,
                        (errcode(ERRCODE_DUPLICATE_COLUMN),
                         errmsg("column name \"%s\" specified more than once",
                                NameStr(TupleDescAttr(tupdesc, j)->attname))));
        }
    }
 
    /*
     * next check the attribute types
     */
    for (i = 0; i < natts; i++)
    {
        Form_pg_attribute attr = TupleDescAttr(tupdesc, i);
 
        if (attr->attisdropped)
            continue;
        CheckAttributeType(NameStr(attr->attname),
                           attr->atttypid,
                           attr->attcollation,
                           NIL, /* assume we're creating a new rowtype */
                           flags | (attr->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL ? CHKATYPE_IS_VIRTUAL : 0));
    }
}
 
/* --------------------------------
 *      CheckAttributeType
 *
 *      Verify that the proposed datatype of an attribute is legal.
 *      This is needed mainly because there are types (and pseudo-types)
 *      in the catalogs that we do not support as elements of real tuples.
 *      We also check some other properties required of a table column.
 *
 * If the attribute is being proposed for addition to an existing table or
 * composite type, pass a one-element list of the rowtype OID as
 * containing_rowtypes.  When checking a to-be-created rowtype, it's
 * sufficient to pass NIL, because there could not be any recursive reference
 * to a not-yet-existing rowtype.
 *
 * flags is a bitmask controlling which datatypes we allow.  For the most
 * part, pseudo-types are disallowed as attribute types, but there are some
 * exceptions: ANYARRAYOID, RECORDOID, and RECORDARRAYOID can be allowed
 * in some cases.  (This works because values of those type classes are
 * self-identifying to some extent.  However, RECORDOID and RECORDARRAYOID
 * are reliably identifiable only within a session, since the identity info
 * may use a typmod that is only locally assigned.  The caller is expected
 * to know whether these cases are safe.)
 *
 * flags can also control the phrasing of the error messages.  If
 * CHKATYPE_IS_PARTKEY is specified, "attname" should be a partition key
 * column number as text, not a real column name.
 * --------------------------------
 */
void
CheckAttributeType(const char *attname,
                   Oid atttypid, Oid attcollation,
                   List *containing_rowtypes,
                   int flags)
{
    char        att_typtype = get_typtype(atttypid);
    Oid         att_typelem;
 
    /* since this function recurses, it could be driven to stack overflow */
    check_stack_depth();
 
    if (att_typtype == TYPTYPE_PSEUDO)
    {
        /*
         * We disallow pseudo-type columns, with the exception of ANYARRAY,
         * RECORD, and RECORD[] when the caller says that those are OK.
         *
         * We don't need to worry about recursive containment for RECORD and
         * RECORD[] because (a) no named composite type should be allowed to
         * contain those, and (b) two "anonymous" record types couldn't be
         * considered to be the same type, so infinite recursion isn't
         * possible.
         */
        if (!((atttypid == ANYARRAYOID && (flags & CHKATYPE_ANYARRAY)) ||
              (atttypid == RECORDOID && (flags & CHKATYPE_ANYRECORD)) ||
              (atttypid == RECORDARRAYOID && (flags & CHKATYPE_ANYRECORD))))
        {
            if (flags & CHKATYPE_IS_PARTKEY)
                ereport(ERROR,
                        (errcode(ERRCODE_INVALID_TABLE_DEFINITION),
                /* translator: first %s is an integer not a name */
                         errmsg("partition key column %s has pseudo-type %s",
                                attname, format_type_be(atttypid))));
            else
                ereport(ERROR,
                        (errcode(ERRCODE_INVALID_TABLE_DEFINITION),
                         errmsg("column \"%s\" has pseudo-type %s",
                                attname, format_type_be(atttypid))));
        }
    }
    else if (att_typtype == TYPTYPE_DOMAIN)
    {
        /*
         * Prevent virtual generated columns from having a domain type.  We
         * would have to enforce domain constraints when columns underlying
         * the generated column change.  This could possibly be implemented,
         * but it's not.
         */
        if (flags & CHKATYPE_IS_VIRTUAL)
            ereport(ERROR,
                    errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
                    errmsg("virtual generated column \"%s\" cannot have a domain type", attname));
 
        /*
         * If it's a domain, recurse to check its base type.
         */
        CheckAttributeType(attname, getBaseType(atttypid), attcollation,
                           containing_rowtypes,
                           flags);
    }
    else if (att_typtype == TYPTYPE_COMPOSITE)
    {
        /*
         * For a composite type, recurse into its attributes.
         */
        Relation    relation;
        TupleDesc   tupdesc;
        int         i;
 
        /*
         * Check for self-containment.  Eventually we might be able to allow
         * this (just return without complaint, if so) but it's not clear how
         * many other places would require anti-recursion defenses before it
         * would be safe to allow tables to contain their own rowtype.
         */
        if (list_member_oid(containing_rowtypes, atttypid))
            ereport(ERROR,
                    (errcode(ERRCODE_INVALID_TABLE_DEFINITION),
                     errmsg("composite type %s cannot be made a member of itself",
                            format_type_be(atttypid))));
 
        containing_rowtypes = lappend_oid(containing_rowtypes, atttypid);
 
        relation = relation_open(get_typ_typrelid(atttypid), AccessShareLock);
 
        tupdesc = RelationGetDescr(relation);
 
        for (i = 0; i < tupdesc->natts; i++)
        {
            Form_pg_attribute attr = TupleDescAttr(tupdesc, i);
 
            if (attr->attisdropped)
                continue;
            CheckAttributeType(NameStr(attr->attname),
                               attr->atttypid, attr->attcollation,
                               containing_rowtypes,
                               flags & ~CHKATYPE_IS_PARTKEY);
        }
 
        relation_close(relation, AccessShareLock);
 
        containing_rowtypes = list_delete_last(containing_rowtypes);
    }
    else if (att_typtype == TYPTYPE_RANGE)
    {
        /*
         * If it's a range, recurse to check its subtype.
         */
        CheckAttributeType(attname, get_range_subtype(atttypid),
                           get_range_collation(atttypid),
                           containing_rowtypes,
                           flags);
    }
    else if (att_typtype == TYPTYPE_MULTIRANGE)
    {
        /*
         * If it's a multirange, recurse to check its plain range type.
         */
        CheckAttributeType(attname, get_multirange_range(atttypid),
                           InvalidOid,  /* range types are not collatable */
                           containing_rowtypes,
                           flags);
    }
    else if (OidIsValid((att_typelem = get_element_type(atttypid))))
    {
        /*
         * Must recurse into array types, too, in case they are composite.
         */
        CheckAttributeType(attname, att_typelem, attcollation,
                           containing_rowtypes,
                           flags);
    }
 
    /*
     * For consistency with check_virtual_generated_security().
     */
    if ((flags & CHKATYPE_IS_VIRTUAL) && atttypid >= FirstUnpinnedObjectId)
        ereport(ERROR,
                errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
                errmsg("virtual generated column \"%s\" cannot have a user-defined type", attname),
                errdetail("Virtual generated columns that make use of user-defined types are not yet supported."));
 
    /*
     * This might not be strictly invalid per SQL standard, but it is pretty
     * useless, and it cannot be dumped, so we must disallow it.
     */
    if (!OidIsValid(attcollation) && type_is_collatable(atttypid))
    {
        if (flags & CHKATYPE_IS_PARTKEY)
            ereport(ERROR,
                    (errcode(ERRCODE_INVALID_TABLE_DEFINITION),
            /* translator: first %s is an integer not a name */
                     errmsg("no collation was derived for partition key column %s with collatable type %s",
                            attname, format_type_be(atttypid)),
                     errhint("Use the COLLATE clause to set the collation explicitly.")));
        else
            ereport(ERROR,
                    (errcode(ERRCODE_INVALID_TABLE_DEFINITION),
                     errmsg("no collation was derived for column \"%s\" with collatable type %s",
                            attname, format_type_be(atttypid)),
                     errhint("Use the COLLATE clause to set the collation explicitly.")));
    }
}
 
/*
 * InsertPgAttributeTuples
 *      Construct and insert a set of tuples in pg_attribute.
 *
 * Caller has already opened and locked pg_attribute.  tupdesc contains the
 * attributes to insert.  tupdesc_extra supplies the values for certain
 * variable-length/nullable pg_attribute fields and must contain the same
 * number of elements as tupdesc or be NULL.  The other variable-length fields
 * of pg_attribute are always initialized to null values.
 *
 * indstate is the index state for CatalogTupleInsertWithInfo.  It can be
 * passed as NULL, in which case we'll fetch the necessary info.  (Don't do
 * this when inserting multiple attributes, because it's a tad more
 * expensive.)
 *
 * new_rel_oid is the relation OID assigned to the attributes inserted.
 * If set to InvalidOid, the relation OID from tupdesc is used instead.
 */
void
InsertPgAttributeTuples(Relation pg_attribute_rel,
                        TupleDesc tupdesc,
                        Oid new_rel_oid,
                        const FormExtraData_pg_attribute tupdesc_extra[],
                        CatalogIndexState indstate)
{
    TupleTableSlot **slot;
    TupleDesc   td;
    int         nslots;
    int         natts = 0;
    int         slotCount = 0;
    bool        close_index = false;
 
    td = RelationGetDescr(pg_attribute_rel);
 
    /* Initialize the number of slots to use */
    nslots = Min(tupdesc->natts,
                 (MAX_CATALOG_MULTI_INSERT_BYTES / sizeof(FormData_pg_attribute)));
    slot = palloc_array(TupleTableSlot *, nslots);
    for (int i = 0; i < nslots; i++)
        slot[i] = MakeSingleTupleTableSlot(td, &TTSOpsHeapTuple);
 
    while (natts < tupdesc->natts)
    {
        Form_pg_attribute attrs = TupleDescAttr(tupdesc, natts);
        const FormExtraData_pg_attribute *attrs_extra = tupdesc_extra ? &tupdesc_extra[natts] : NULL;
 
        ExecClearTuple(slot[slotCount]);
 
        memset(slot[slotCount]->tts_isnull, false,
               slot[slotCount]->tts_tupleDescriptor->natts * sizeof(bool));
 
        if (new_rel_oid != InvalidOid)
            slot[slotCount]->tts_values[Anum_pg_attribute_attrelid - 1] = ObjectIdGetDatum(new_rel_oid);
        else
            slot[slotCount]->tts_values[Anum_pg_attribute_attrelid - 1] = ObjectIdGetDatum(attrs->attrelid);
 
        slot[slotCount]->tts_values[Anum_pg_attribute_attname - 1] = NameGetDatum(&attrs->attname);
        slot[slotCount]->tts_values[Anum_pg_attribute_atttypid - 1] = ObjectIdGetDatum(attrs->atttypid);
        slot[slotCount]->tts_values[Anum_pg_attribute_attlen - 1] = Int16GetDatum(attrs->attlen);
        slot[slotCount]->tts_values[Anum_pg_attribute_attnum - 1] = Int16GetDatum(attrs->attnum);
        slot[slotCount]->tts_values[Anum_pg_attribute_atttypmod - 1] = Int32GetDatum(attrs->atttypmod);
        slot[slotCount]->tts_values[Anum_pg_attribute_attndims - 1] = Int16GetDatum(attrs->attndims);
        slot[slotCount]->tts_values[Anum_pg_attribute_attbyval - 1] = BoolGetDatum(attrs->attbyval);
        slot[slotCount]->tts_values[Anum_pg_attribute_attalign - 1] = CharGetDatum(attrs->attalign);
        slot[slotCount]->tts_values[Anum_pg_attribute_attstorage - 1] = CharGetDatum(attrs->attstorage);
        slot[slotCount]->tts_values[Anum_pg_attribute_attcompression - 1] = CharGetDatum(attrs->attcompression);
        slot[slotCount]->tts_values[Anum_pg_attribute_attnotnull - 1] = BoolGetDatum(attrs->attnotnull);
        slot[slotCount]->tts_values[Anum_pg_attribute_atthasdef - 1] = BoolGetDatum(attrs->atthasdef);
        slot[slotCount]->tts_values[Anum_pg_attribute_atthasmissing - 1] = BoolGetDatum(attrs->atthasmissing);
        slot[slotCount]->tts_values[Anum_pg_attribute_attidentity - 1] = CharGetDatum(attrs->attidentity);
        slot[slotCount]->tts_values[Anum_pg_attribute_attgenerated - 1] = CharGetDatum(attrs->attgenerated);
        slot[slotCount]->tts_values[Anum_pg_attribute_attisdropped - 1] = BoolGetDatum(attrs->attisdropped);
        slot[slotCount]->tts_values[Anum_pg_attribute_attislocal - 1] = BoolGetDatum(attrs->attislocal);
        slot[slotCount]->tts_values[Anum_pg_attribute_attinhcount - 1] = Int16GetDatum(attrs->attinhcount);
        slot[slotCount]->tts_values[Anum_pg_attribute_attcollation - 1] = ObjectIdGetDatum(attrs->attcollation);
        if (attrs_extra)
        {
            slot[slotCount]->tts_values[Anum_pg_attribute_attstattarget - 1] = attrs_extra->attstattarget.value;
            slot[slotCount]->tts_isnull[Anum_pg_attribute_attstattarget - 1] = attrs_extra->attstattarget.isnull;
 
            slot[slotCount]->tts_values[Anum_pg_attribute_attoptions - 1] = attrs_extra->attoptions.value;
            slot[slotCount]->tts_isnull[Anum_pg_attribute_attoptions - 1] = attrs_extra->attoptions.isnull;
        }
        else
        {
            slot[slotCount]->tts_isnull[Anum_pg_attribute_attstattarget - 1] = true;
            slot[slotCount]->tts_isnull[Anum_pg_attribute_attoptions - 1] = true;
        }
 
        /*
         * The remaining fields are not set for new columns.
         */
        slot[slotCount]->tts_isnull[Anum_pg_attribute_attacl - 1] = true;
        slot[slotCount]->tts_isnull[Anum_pg_attribute_attfdwoptions - 1] = true;
        slot[slotCount]->tts_isnull[Anum_pg_attribute_attmissingval - 1] = true;
 
        ExecStoreVirtualTuple(slot[slotCount]);
        slotCount++;
 
        /*
         * If slots are full or the end of processing has been reached, insert
         * a batch of tuples.
         */
        if (slotCount == nslots || natts == tupdesc->natts - 1)
        {
            /* fetch index info only when we know we need it */
            if (!indstate)
            {
                indstate = CatalogOpenIndexes(pg_attribute_rel);
                close_index = true;
            }
 
            /* insert the new tuples and update the indexes */
            CatalogTuplesMultiInsertWithInfo(pg_attribute_rel, slot, slotCount,
                                             indstate);
            slotCount = 0;
        }
 
        natts++;
    }
 
    if (close_index)
        CatalogCloseIndexes(indstate);
    for (int i = 0; i < nslots; i++)
        ExecDropSingleTupleTableSlot(slot[i]);
    pfree(slot);
}
 
/* --------------------------------
 *      AddNewAttributeTuples
 *
 *      this registers the new relation's schema by adding
 *      tuples to pg_attribute.
 * --------------------------------
 */
static void
AddNewAttributeTuples(Oid new_rel_oid,
                      TupleDesc tupdesc,
                      char relkind)
{
    Relation    rel;
    CatalogIndexState indstate;
    int         natts = tupdesc->natts;
    ObjectAddress myself,
                referenced;
 
    /*
     * open pg_attribute and its indexes.
     */
    rel = table_open(AttributeRelationId, RowExclusiveLock);
 
    indstate = CatalogOpenIndexes(rel);
 
    InsertPgAttributeTuples(rel, tupdesc, new_rel_oid, NULL, indstate);
 
    /* add dependencies on their datatypes and collations */
    for (int i = 0; i < natts; i++)
    {
        Form_pg_attribute attr = TupleDescAttr(tupdesc, i);
 
        /* Add dependency info */
        ObjectAddressSubSet(myself, RelationRelationId, new_rel_oid, i + 1);
        ObjectAddressSet(referenced, TypeRelationId, attr->atttypid);
        recordDependencyOn(&myself, &referenced, DEPENDENCY_NORMAL);
 
        /* The default collation is pinned, so don't bother recording it */
        if (OidIsValid(attr->attcollation) &&
            attr->attcollation != DEFAULT_COLLATION_OID)
        {
            ObjectAddressSet(referenced, CollationRelationId,
                             attr->attcollation);
            recordDependencyOn(&myself, &referenced, DEPENDENCY_NORMAL);
        }
    }
 
    /*
     * Next we add the system attributes.  Skip all for a view or type
     * relation.  We don't bother with making datatype dependencies here,
     * since presumably all these types are pinned.
     */
    if (relkind != RELKIND_VIEW && relkind != RELKIND_COMPOSITE_TYPE)
    {
        TupleDesc   td;
 
        td = CreateTupleDesc(lengthof(SysAtt), (FormData_pg_attribute **) &SysAtt);
 
        InsertPgAttributeTuples(rel, td, new_rel_oid, NULL, indstate);
        FreeTupleDesc(td);
    }
 
    /*
     * clean up
     */
    CatalogCloseIndexes(indstate);
 
    table_close(rel, RowExclusiveLock);
}
 
/* --------------------------------
 *      InsertPgClassTuple
 *
 *      Construct and insert a new tuple in pg_class.
 *
 * Caller has already opened and locked pg_class.
 * Tuple data is taken from new_rel_desc->rd_rel, except for the
 * variable-width fields which are not present in a cached reldesc.
 * relacl and reloptions are passed in Datum form (to avoid having
 * to reference the data types in heap.h).  Pass (Datum) 0 to set them
 * to NULL.
 * --------------------------------
 */
void
InsertPgClassTuple(Relation pg_class_desc,
                   Relation new_rel_desc,
                   Oid new_rel_oid,
                   Datum relacl,
                   Datum reloptions)
{
    Form_pg_class rd_rel = new_rel_desc->rd_rel;
    Datum       values[Natts_pg_class];
    bool        nulls[Natts_pg_class];
    HeapTuple   tup;
 
    /* This is a tad tedious, but way cleaner than what we used to do... */
    memset(values, 0, sizeof(values));
    memset(nulls, false, sizeof(nulls));
 
    values[Anum_pg_class_oid - 1] = ObjectIdGetDatum(new_rel_oid);
    values[Anum_pg_class_relname - 1] = NameGetDatum(&rd_rel->relname);
    values[Anum_pg_class_relnamespace - 1] = ObjectIdGetDatum(rd_rel->relnamespace);
    values[Anum_pg_class_reltype - 1] = ObjectIdGetDatum(rd_rel->reltype);
    values[Anum_pg_class_reloftype - 1] = ObjectIdGetDatum(rd_rel->reloftype);
    values[Anum_pg_class_relowner - 1] = ObjectIdGetDatum(rd_rel->relowner);
    values[Anum_pg_class_relam - 1] = ObjectIdGetDatum(rd_rel->relam);
    values[Anum_pg_class_relfilenode - 1] = ObjectIdGetDatum(rd_rel->relfilenode);
    values[Anum_pg_class_reltablespace - 1] = ObjectIdGetDatum(rd_rel->reltablespace);
    values[Anum_pg_class_relpages - 1] = Int32GetDatum(rd_rel->relpages);
    values[Anum_pg_class_reltuples - 1] = Float4GetDatum(rd_rel->reltuples);
    values[Anum_pg_class_relallvisible - 1] = Int32GetDatum(rd_rel->relallvisible);
    values[Anum_pg_class_relallfrozen - 1] = Int32GetDatum(rd_rel->relallfrozen);
    values[Anum_pg_class_reltoastrelid - 1] = ObjectIdGetDatum(rd_rel->reltoastrelid);
    values[Anum_pg_class_relhasindex - 1] = BoolGetDatum(rd_rel->relhasindex);
    values[Anum_pg_class_relisshared - 1] = BoolGetDatum(rd_rel->relisshared);
    values[Anum_pg_class_relpersistence - 1] = CharGetDatum(rd_rel->relpersistence);
    values[Anum_pg_class_relkind - 1] = CharGetDatum(rd_rel->relkind);
    values[Anum_pg_class_relnatts - 1] = Int16GetDatum(rd_rel->relnatts);
    values[Anum_pg_class_relchecks - 1] = Int16GetDatum(rd_rel->relchecks);
    values[Anum_pg_class_relhasrules - 1] = BoolGetDatum(rd_rel->relhasrules);
    values[Anum_pg_class_relhastriggers - 1] = BoolGetDatum(rd_rel->relhastriggers);
    values[Anum_pg_class_relrowsecurity - 1] = BoolGetDatum(rd_rel->relrowsecurity);
    values[Anum_pg_class_relforcerowsecurity - 1] = BoolGetDatum(rd_rel->relforcerowsecurity);
    values[Anum_pg_class_relhassubclass - 1] = BoolGetDatum(rd_rel->relhassubclass);
    values[Anum_pg_class_relispopulated - 1] = BoolGetDatum(rd_rel->relispopulated);
    values[Anum_pg_class_relreplident - 1] = CharGetDatum(rd_rel->relreplident);
    values[Anum_pg_class_relispartition - 1] = BoolGetDatum(rd_rel->relispartition);
    values[Anum_pg_class_relrewrite - 1] = ObjectIdGetDatum(rd_rel->relrewrite);
    values[Anum_pg_class_relfrozenxid - 1] = TransactionIdGetDatum(rd_rel->relfrozenxid);
    values[Anum_pg_class_relminmxid - 1] = MultiXactIdGetDatum(rd_rel->relminmxid);
    if (relacl != (Datum) 0)
        values[Anum_pg_class_relacl - 1] = relacl;
    else
        nulls[Anum_pg_class_relacl - 1] = true;
    if (reloptions != (Datum) 0)
        values[Anum_pg_class_reloptions - 1] = reloptions;
    else
        nulls[Anum_pg_class_reloptions - 1] = true;
 
    /* relpartbound is set by updating this tuple, if necessary */
    nulls[Anum_pg_class_relpartbound - 1] = true;
 
    tup = heap_form_tuple(RelationGetDescr(pg_class_desc), values, nulls);
 
    /* finally insert the new tuple, update the indexes, and clean up */
    CatalogTupleInsert(pg_class_desc, tup);
 
    heap_freetuple(tup);
}
 
/* --------------------------------
 *      AddNewRelationTuple
 *
 *      this registers the new relation in the catalogs by
 *      adding a tuple to pg_class.
 * --------------------------------
 */
static void
AddNewRelationTuple(Relation pg_class_desc,
                    Relation new_rel_desc,
                    Oid new_rel_oid,
                    Oid new_type_oid,
                    Oid reloftype,
                    Oid relowner,
                    char relkind,
                    TransactionId relfrozenxid,
                    TransactionId relminmxid,
                    Datum relacl,
                    Datum reloptions)
{
    Form_pg_class new_rel_reltup;
 
    /*
     * first we update some of the information in our uncataloged relation's
     * relation descriptor.
     */
    new_rel_reltup = new_rel_desc->rd_rel;
 
    /* The relation is empty */
    new_rel_reltup->relpages = 0;
    new_rel_reltup->reltuples = -1;
    new_rel_reltup->relallvisible = 0;
    new_rel_reltup->relallfrozen = 0;
 
    /* Sequences always have a known size */
    if (relkind == RELKIND_SEQUENCE)
    {
        new_rel_reltup->relpages = 1;
        new_rel_reltup->reltuples = 1;
    }
 
    new_rel_reltup->relfrozenxid = relfrozenxid;
    new_rel_reltup->relminmxid = relminmxid;
    new_rel_reltup->relowner = relowner;
    new_rel_reltup->reltype = new_type_oid;
    new_rel_reltup->reloftype = reloftype;
 
    /* relispartition is always set by updating this tuple later */
    new_rel_reltup->relispartition = false;
 
    /* fill rd_att's type ID with something sane even if reltype is zero */
    new_rel_desc->rd_att->tdtypeid = new_type_oid ? new_type_oid : RECORDOID;
    new_rel_desc->rd_att->tdtypmod = -1;
 
    /* Now build and insert the tuple */
    InsertPgClassTuple(pg_class_desc, new_rel_desc, new_rel_oid,
                       relacl, reloptions);
}
 
 
/* --------------------------------
 *      AddNewRelationType -
 *
 *      define a composite type corresponding to the new relation
 * --------------------------------
 */
static ObjectAddress
AddNewRelationType(const char *typeName,
                   Oid typeNamespace,
                   Oid new_rel_oid,
                   char new_rel_kind,
                   Oid ownerid,
                   Oid new_row_type,
                   Oid new_array_type)
{
    return
        TypeCreate(new_row_type,    /* optional predetermined OID */
                   typeName,    /* type name */
                   typeNamespace,   /* type namespace */
                   new_rel_oid, /* relation oid */
                   new_rel_kind,    /* relation kind */
                   ownerid,     /* owner's ID */
                   -1,          /* internal size (varlena) */
                   TYPTYPE_COMPOSITE,   /* type-type (composite) */
                   TYPCATEGORY_COMPOSITE,   /* type-category (ditto) */
                   false,       /* composite types are never preferred */
                   DEFAULT_TYPDELIM,    /* default array delimiter */
                   F_RECORD_IN, /* input procedure */
                   F_RECORD_OUT,    /* output procedure */
                   F_RECORD_RECV,   /* receive procedure */
                   F_RECORD_SEND,   /* send procedure */
                   InvalidOid,  /* typmodin procedure - none */
                   InvalidOid,  /* typmodout procedure - none */
                   InvalidOid,  /* analyze procedure - default */
                   InvalidOid,  /* subscript procedure - none */
                   InvalidOid,  /* array element type - irrelevant */
                   false,       /* this is not an array type */
                   new_array_type,  /* array type if any */
                   InvalidOid,  /* domain base type - irrelevant */
                   NULL,        /* default value - none */
                   NULL,        /* default binary representation */
                   false,       /* passed by reference */
                   TYPALIGN_DOUBLE, /* alignment - must be the largest! */
                   TYPSTORAGE_EXTENDED, /* fully TOASTable */
                   -1,          /* typmod */
                   0,           /* array dimensions for typBaseType */
                   false,       /* Type NOT NULL */
                   InvalidOid); /* rowtypes never have a collation */
}
 
/* --------------------------------
 *      heap_create_with_catalog
 *
 *      creates a new cataloged relation.  see comments above.
 *
 * Arguments:
 *  relname: name to give to new rel
 *  relnamespace: OID of namespace it goes in
 *  reltablespace: OID of tablespace it goes in
 *  relid: OID to assign to new rel, or InvalidOid to select a new OID
 *  reltypeid: OID to assign to rel's rowtype, or InvalidOid to select one
 *  reloftypeid: if a typed table, OID of underlying type; else InvalidOid
 *  ownerid: OID of new rel's owner
 *  accessmtd: OID of new rel's access method
 *  tupdesc: tuple descriptor (source of column definitions)
 *  cooked_constraints: list of precooked check constraints and defaults
 *  relkind: relkind for new rel
 *  relpersistence: rel's persistence status (permanent, temp, or unlogged)
 *  shared_relation: true if it's to be a shared relation
 *  mapped_relation: true if the relation will use the relfilenumber map
 *  oncommit: ON COMMIT marking (only relevant if it's a temp table)
 *  reloptions: reloptions in Datum form, or (Datum) 0 if none
 *  use_user_acl: true if should look for user-defined default permissions;
 *      if false, relacl is always set NULL
 *  allow_system_table_mods: true to allow creation in system namespaces
 *  is_internal: is this a system-generated catalog?
 *  relrewrite: link to original relation during a table rewrite
 *
 * Output parameters:
 *  typaddress: if not null, gets the object address of the new pg_type entry
 *  (this must be null if the relkind is one that doesn't get a pg_type entry)
 *
 * Returns the OID of the new relation
 * --------------------------------
 */
Oid
heap_create_with_catalog(const char *relname,
                         Oid relnamespace,
                         Oid reltablespace,
                         Oid relid,
                         Oid reltypeid,
                         Oid reloftypeid,
                         Oid ownerid,
                         Oid accessmtd,
                         TupleDesc tupdesc,
                         List *cooked_constraints,
                         char relkind,
                         char relpersistence,
                         bool shared_relation,
                         bool mapped_relation,
                         OnCommitAction oncommit,
                         Datum reloptions,
                         bool use_user_acl,
                         bool allow_system_table_mods,
                         bool is_internal,
                         Oid relrewrite,
                         ObjectAddress *typaddress)
{
    Relation    pg_class_desc;
    Relation    new_rel_desc;
    Acl        *relacl;
    Oid         existing_relid;
    Oid         old_type_oid;
    Oid         new_type_oid;
 
    /* By default set to InvalidOid unless overridden by binary-upgrade */
    RelFileNumber relfilenumber = InvalidRelFileNumber;
    TransactionId relfrozenxid;
    MultiXactId relminmxid;
 
    pg_class_desc = table_open(RelationRelationId, RowExclusiveLock);
 
    /*
     * sanity checks
     */
    Assert(IsNormalProcessingMode() || IsBootstrapProcessingMode());
 
    /*
     * Validate proposed tupdesc for the desired relkind.  If
     * allow_system_table_mods is on, allow ANYARRAY to be used; this is a
     * hack to allow creating pg_statistic and cloning it during VACUUM FULL.
     */
    CheckAttributeNamesTypes(tupdesc, relkind,
                             allow_system_table_mods ? CHKATYPE_ANYARRAY : 0);
 
    /*
     * This would fail later on anyway, if the relation already exists.  But
     * by catching it here we can emit a nicer error message.
     */
    existing_relid = get_relname_relid(relname, relnamespace);
    if (existing_relid != InvalidOid)
        ereport(ERROR,
                (errcode(ERRCODE_DUPLICATE_TABLE),
                 errmsg("relation \"%s\" already exists", relname)));
 
    /*
     * Since we are going to create a rowtype as well, also check for
     * collision with an existing type name.  If there is one and it's an
     * autogenerated array, we can rename it out of the way; otherwise we can
     * at least give a good error message.
     */
    old_type_oid = GetSysCacheOid2(TYPENAMENSP, Anum_pg_type_oid,
                                   CStringGetDatum(relname),
                                   ObjectIdGetDatum(relnamespace));
    if (OidIsValid(old_type_oid))
    {
        if (!moveArrayTypeName(old_type_oid, relname, relnamespace))
            ereport(ERROR,
                    (errcode(ERRCODE_DUPLICATE_OBJECT),
                     errmsg("type \"%s\" already exists", relname),
                     errhint("A relation has an associated type of the same name, "
                             "so you must use a name that doesn't conflict "
                             "with any existing type.")));
    }
 
    /*
     * Shared relations must be in pg_global (last-ditch check)
     */
    if (shared_relation && reltablespace != GLOBALTABLESPACE_OID)
        elog(ERROR, "shared relations must be placed in pg_global tablespace");
 
    /*
     * Allocate an OID for the relation, unless we were told what to use.
     *
     * The OID will be the relfilenumber as well, so make sure it doesn't
     * collide with either pg_class OIDs or existing physical files.
     */
    if (!OidIsValid(relid))
    {
        /* Use binary-upgrade override for pg_class.oid and relfilenumber */
        if (IsBinaryUpgrade)
        {
            /*
             * Indexes are not supported here; they use
             * binary_upgrade_next_index_pg_class_oid.
             */
            Assert(relkind != RELKIND_INDEX);
            Assert(relkind != RELKIND_PARTITIONED_INDEX);
 
            if (relkind == RELKIND_TOASTVALUE)
            {
                /* There might be no TOAST table, so we have to test for it. */
                if (OidIsValid(binary_upgrade_next_toast_pg_class_oid))
                {
                    relid = binary_upgrade_next_toast_pg_class_oid;
                    binary_upgrade_next_toast_pg_class_oid = InvalidOid;
 
                    if (!RelFileNumberIsValid(binary_upgrade_next_toast_pg_class_relfilenumber))
                        ereport(ERROR,
                                (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
                                 errmsg("toast relfilenumber value not set when in binary upgrade mode")));
 
                    relfilenumber = binary_upgrade_next_toast_pg_class_relfilenumber;
                    binary_upgrade_next_toast_pg_class_relfilenumber = InvalidRelFileNumber;
                }
            }
            else
            {
                if (!OidIsValid(binary_upgrade_next_heap_pg_class_oid))
                    ereport(ERROR,
                            (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
                             errmsg("pg_class heap OID value not set when in binary upgrade mode")));
 
                relid = binary_upgrade_next_heap_pg_class_oid;
                binary_upgrade_next_heap_pg_class_oid = InvalidOid;
 
                if (RELKIND_HAS_STORAGE(relkind))
                {
                    if (!RelFileNumberIsValid(binary_upgrade_next_heap_pg_class_relfilenumber))
                        ereport(ERROR,
                                (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
                                 errmsg("relfilenumber value not set when in binary upgrade mode")));
 
                    relfilenumber = binary_upgrade_next_heap_pg_class_relfilenumber;
                    binary_upgrade_next_heap_pg_class_relfilenumber = InvalidRelFileNumber;
                }
            }
        }
 
        if (!OidIsValid(relid))
            relid = GetNewRelFileNumber(reltablespace, pg_class_desc,
                                        relpersistence);
    }
 
    /*
     * Other sessions' catalog scans can't find this until we commit.  Hence,
     * it doesn't hurt to hold AccessExclusiveLock.  Do it here so callers
     * can't accidentally vary in their lock mode or acquisition timing.
     */
    LockRelationOid(relid, AccessExclusiveLock);
 
    /*
     * Determine the relation's initial permissions.
     */
    if (use_user_acl)
    {
        switch (relkind)
        {
            case RELKIND_RELATION:
            case RELKIND_VIEW:
            case RELKIND_MATVIEW:
            case RELKIND_FOREIGN_TABLE:
            case RELKIND_PARTITIONED_TABLE:
                relacl = get_user_default_acl(OBJECT_TABLE, ownerid,
                                              relnamespace);
                break;
            case RELKIND_SEQUENCE:
                relacl = get_user_default_acl(OBJECT_SEQUENCE, ownerid,
                                              relnamespace);
                break;
            default:
                relacl = NULL;
                break;
        }
    }
    else
        relacl = NULL;
 
    /*
     * Create the relcache entry (mostly dummy at this point) and the physical
     * disk file.  (If we fail further down, it's the smgr's responsibility to
     * remove the disk file again.)
     *
     * NB: Note that passing create_storage = true is correct even for binary
     * upgrade.  The storage we create here will be replaced later, but we
     * need to have something on disk in the meanwhile.
     */
    new_rel_desc = heap_create(relname,
                               relnamespace,
                               reltablespace,
                               relid,
                               relfilenumber,
                               accessmtd,
                               tupdesc,
                               relkind,
                               relpersistence,
                               shared_relation,
                               mapped_relation,
                               allow_system_table_mods,
                               &relfrozenxid,
                               &relminmxid,
                               true);
 
    Assert(relid == RelationGetRelid(new_rel_desc));
 
    new_rel_desc->rd_rel->relrewrite = relrewrite;
 
    /*
     * Decide whether to create a pg_type entry for the relation's rowtype.
     * These types are made except where the use of a relation as such is an
     * implementation detail: toast tables, sequences, indexes, and property
     * graphs.
     */
    if (!(relkind == RELKIND_SEQUENCE ||
          relkind == RELKIND_TOASTVALUE ||
          relkind == RELKIND_INDEX ||
          relkind == RELKIND_PARTITIONED_INDEX ||
          relkind == RELKIND_PROPGRAPH))
    {
        Oid         new_array_oid;
        ObjectAddress new_type_addr;
        char       *relarrayname;
 
        /*
         * We'll make an array over the composite type, too.  For largely
         * historical reasons, the array type's OID is assigned first.
         */
        new_array_oid = AssignTypeArrayOid();
 
        /*
         * Make the pg_type entry for the composite type.  The OID of the
         * composite type can be preselected by the caller, but if reltypeid
         * is InvalidOid, we'll generate a new OID for it.
         *
         * NOTE: we could get a unique-index failure here, in case someone
         * else is creating the same type name in parallel but hadn't
         * committed yet when we checked for a duplicate name above.
         */
        new_type_addr = AddNewRelationType(relname,
                                           relnamespace,
                                           relid,
                                           relkind,
                                           ownerid,
                                           reltypeid,
                                           new_array_oid);
        new_type_oid = new_type_addr.objectId;
        if (typaddress)
            *typaddress = new_type_addr;
 
        /* Now create the array type. */
        relarrayname = makeArrayTypeName(relname, relnamespace);
 
        TypeCreate(new_array_oid,   /* force the type's OID to this */
                   relarrayname,    /* Array type name */
                   relnamespace,    /* Same namespace as parent */
                   InvalidOid,  /* Not composite, no relationOid */
                   0,           /* relkind, also N/A here */
                   ownerid,     /* owner's ID */
                   -1,          /* Internal size (varlena) */
                   TYPTYPE_BASE,    /* Not composite - typelem is */
                   TYPCATEGORY_ARRAY,   /* type-category (array) */
                   false,       /* array types are never preferred */
                   DEFAULT_TYPDELIM,    /* default array delimiter */
                   F_ARRAY_IN,  /* array input proc */
                   F_ARRAY_OUT, /* array output proc */
                   F_ARRAY_RECV,    /* array recv (bin) proc */
                   F_ARRAY_SEND,    /* array send (bin) proc */
                   InvalidOid,  /* typmodin procedure - none */
                   InvalidOid,  /* typmodout procedure - none */
                   F_ARRAY_TYPANALYZE,  /* array analyze procedure */
                   F_ARRAY_SUBSCRIPT_HANDLER,   /* array subscript procedure */
                   new_type_oid,    /* array element type - the rowtype */
                   true,        /* yes, this is an array type */
                   InvalidOid,  /* this has no array type */
                   InvalidOid,  /* domain base type - irrelevant */
                   NULL,        /* default value - none */
                   NULL,        /* default binary representation */
                   false,       /* passed by reference */
                   TYPALIGN_DOUBLE, /* alignment - must be the largest! */
                   TYPSTORAGE_EXTENDED, /* fully TOASTable */
                   -1,          /* typmod */
                   0,           /* array dimensions for typBaseType */
                   false,       /* Type NOT NULL */
                   InvalidOid); /* rowtypes never have a collation */
 
        pfree(relarrayname);
    }
    else
    {
        /* Caller should not be expecting a type to be created. */
        Assert(reltypeid == InvalidOid);
        Assert(typaddress == NULL);
 
        new_type_oid = InvalidOid;
    }
 
    /*
     * now create an entry in pg_class for the relation.
     *
     * NOTE: we could get a unique-index failure here, in case someone else is
     * creating the same relation name in parallel but hadn't committed yet
     * when we checked for a duplicate name above.
     */
    AddNewRelationTuple(pg_class_desc,
                        new_rel_desc,
                        relid,
                        new_type_oid,
                        reloftypeid,
                        ownerid,
                        relkind,
                        relfrozenxid,
                        relminmxid,
                        PointerGetDatum(relacl),
                        reloptions);
 
    /*
     * now add tuples to pg_attribute for the attributes in our new relation.
     */
    AddNewAttributeTuples(relid, new_rel_desc->rd_att, relkind);
 
    /*
     * Make a dependency link to force the relation to be deleted if its
     * namespace is.  Also make a dependency link to its owner, as well as
     * dependencies for any roles mentioned in the default ACL.
     *
     * For composite types, these dependencies are tracked for the pg_type
     * entry, so we needn't record them here.  Likewise, TOAST tables don't
     * need a namespace dependency (they live in a pinned namespace) nor an
     * owner dependency (they depend indirectly through the parent table), nor
     * should they have any ACL entries.  The same applies for extension
     * dependencies.
     *
     * Also, skip this in bootstrap mode, since we don't make dependencies
     * while bootstrapping.
     */
    if (relkind != RELKIND_COMPOSITE_TYPE &&
        relkind != RELKIND_TOASTVALUE &&
        !IsBootstrapProcessingMode())
    {
        ObjectAddress myself,
                    referenced;
        ObjectAddresses *addrs;
 
        ObjectAddressSet(myself, RelationRelationId, relid);
 
        recordDependencyOnOwner(RelationRelationId, relid, ownerid);
 
        recordDependencyOnNewAcl(RelationRelationId, relid, 0, ownerid, relacl);
 
        recordDependencyOnCurrentExtension(&myself, false);
 
        addrs = new_object_addresses();
 
        ObjectAddressSet(referenced, NamespaceRelationId, relnamespace);
        add_exact_object_address(&referenced, addrs);
 
        if (reloftypeid)
        {
            ObjectAddressSet(referenced, TypeRelationId, reloftypeid);
            add_exact_object_address(&referenced, addrs);
        }
 
        /*
         * Make a dependency link to force the relation to be deleted if its
         * access method is.
         *
         * No need to add an explicit dependency for the toast table, as the
         * main table depends on it.  Partitioned tables may not have an
         * access method set.
         */
        if ((RELKIND_HAS_TABLE_AM(relkind) && relkind != RELKIND_TOASTVALUE) ||
            (relkind == RELKIND_PARTITIONED_TABLE && OidIsValid(accessmtd)))
        {
            ObjectAddressSet(referenced, AccessMethodRelationId, accessmtd);
            add_exact_object_address(&referenced, addrs);
        }
 
        record_object_address_dependencies(&myself, addrs, DEPENDENCY_NORMAL);
        free_object_addresses(addrs);
    }
 
    /* Post creation hook for new relation */
    InvokeObjectPostCreateHookArg(RelationRelationId, relid, 0, is_internal);
 
    /*
     * Store any supplied CHECK constraints and defaults.
     *
     * NB: this may do a CommandCounterIncrement and rebuild the relcache
     * entry, so the relation must be valid and self-consistent at this point.
     * In particular, there are not yet constraints and defaults anywhere.
     */
    StoreConstraints(new_rel_desc, cooked_constraints, is_internal);
 
    /*
     * If there's a special on-commit action, remember it
     */
    if (oncommit != ONCOMMIT_NOOP)
        register_on_commit_action(relid, oncommit);
 
    /*
     * ok, the relation has been cataloged, so close our relations and return
     * the OID of the newly created relation.
     */
    table_close(new_rel_desc, NoLock);  /* do not unlock till end of xact */
    table_close(pg_class_desc, RowExclusiveLock);
 
    return relid;
}
 
/*
 *      RelationRemoveInheritance
 *
 * Formerly, this routine checked for child relations and aborted the
 * deletion if any were found.  Now we rely on the dependency mechanism
 * to check for or delete child relations.  By the time we get here,
 * there are no children and we need only remove any pg_inherits rows
 * linking this relation to its parent(s).
 */
static void
RelationRemoveInheritance(Oid relid)
{
    Relation    catalogRelation;
    SysScanDesc scan;
    ScanKeyData key;
    HeapTuple   tuple;
 
    catalogRelation = table_open(InheritsRelationId, RowExclusiveLock);
 
    ScanKeyInit(&key,
                Anum_pg_inherits_inhrelid,
                BTEqualStrategyNumber, F_OIDEQ,
                ObjectIdGetDatum(relid));
 
    scan = systable_beginscan(catalogRelation, InheritsRelidSeqnoIndexId, true,
                              NULL, 1, &key);
 
    while (HeapTupleIsValid(tuple = systable_getnext(scan)))
        CatalogTupleDelete(catalogRelation, &tuple->t_self);
 
    systable_endscan(scan);
    table_close(catalogRelation, RowExclusiveLock);
}
 
/*
 *      DeleteRelationTuple
 *
 * Remove pg_class row for the given relid.
 *
 * Note: this is shared by relation deletion and index deletion.  It's
 * not intended for use anyplace else.
 */
void
DeleteRelationTuple(Oid relid)
{
    Relation    pg_class_desc;
    HeapTuple   tup;
 
    /* Grab an appropriate lock on the pg_class relation */
    pg_class_desc = table_open(RelationRelationId, RowExclusiveLock);
 
    tup = SearchSysCache1(RELOID, ObjectIdGetDatum(relid));
    if (!HeapTupleIsValid(tup))
        elog(ERROR, "cache lookup failed for relation %u", relid);
 
    /* delete the relation tuple from pg_class, and finish up */
    CatalogTupleDelete(pg_class_desc, &tup->t_self);
 
    ReleaseSysCache(tup);
 
    table_close(pg_class_desc, RowExclusiveLock);
}
 
/*
 *      DeleteAttributeTuples
 *
 * Remove pg_attribute rows for the given relid.
 *
 * Note: this is shared by relation deletion and index deletion.  It's
 * not intended for use anyplace else.
 */
void
DeleteAttributeTuples(Oid relid)
{
    Relation    attrel;
    SysScanDesc scan;
    ScanKeyData key[1];
    HeapTuple   atttup;
 
    /* Grab an appropriate lock on the pg_attribute relation */
    attrel = table_open(AttributeRelationId, RowExclusiveLock);
 
    /* Use the index to scan only attributes of the target relation */
    ScanKeyInit(&key[0],
                Anum_pg_attribute_attrelid,
                BTEqualStrategyNumber, F_OIDEQ,
                ObjectIdGetDatum(relid));
 
    scan = systable_beginscan(attrel, AttributeRelidNumIndexId, true,
                              NULL, 1, key);
 
    /* Delete all the matching tuples */
    while ((atttup = systable_getnext(scan)) != NULL)
        CatalogTupleDelete(attrel, &atttup->t_self);
 
    /* Clean up after the scan */
    systable_endscan(scan);
    table_close(attrel, RowExclusiveLock);
}
 
/*
 *      DeleteSystemAttributeTuples
 *
 * Remove pg_attribute rows for system columns of the given relid.
 *
 * Note: this is only used when converting a table to a view.  Views don't
 * have system columns, so we should remove them from pg_attribute.
 */
void
DeleteSystemAttributeTuples(Oid relid)
{
    Relation    attrel;
    SysScanDesc scan;
    ScanKeyData key[2];
    HeapTuple   atttup;
 
    /* Grab an appropriate lock on the pg_attribute relation */
    attrel = table_open(AttributeRelationId, RowExclusiveLock);
 
    /* Use the index to scan only system attributes of the target relation */
    ScanKeyInit(&key[0],
                Anum_pg_attribute_attrelid,
                BTEqualStrategyNumber, F_OIDEQ,
                ObjectIdGetDatum(relid));
    ScanKeyInit(&key[1],
                Anum_pg_attribute_attnum,
                BTLessEqualStrategyNumber, F_INT2LE,
                Int16GetDatum(0));
 
    scan = systable_beginscan(attrel, AttributeRelidNumIndexId, true,
                              NULL, 2, key);
 
    /* Delete all the matching tuples */
    while ((atttup = systable_getnext(scan)) != NULL)
        CatalogTupleDelete(attrel, &atttup->t_self);
 
    /* Clean up after the scan */
    systable_endscan(scan);
    table_close(attrel, RowExclusiveLock);
}
 
/*
 *      RemoveAttributeById
 *
 * This is the guts of ALTER TABLE DROP COLUMN: actually mark the attribute
 * deleted in pg_attribute.  We also remove pg_statistic entries for it.
 * (Everything else needed, such as getting rid of any pg_attrdef entry,
 * is handled by dependency.c.)
 */
void
RemoveAttributeById(Oid relid, AttrNumber attnum)
{
    Relation    rel;
    Relation    attr_rel;
    HeapTuple   tuple;
    Form_pg_attribute attStruct;
    char        newattname[NAMEDATALEN];
    Datum       valuesAtt[Natts_pg_attribute] = {0};
    bool        nullsAtt[Natts_pg_attribute] = {0};
    bool        replacesAtt[Natts_pg_attribute] = {0};
 
    /*
     * Grab an exclusive lock on the target table, which we will NOT release
     * until end of transaction.  (In the simple case where we are directly
     * dropping this column, ATExecDropColumn already did this ... but when
     * cascading from a drop of some other object, we may not have any lock.)
     */
    rel = relation_open(relid, AccessExclusiveLock);
 
    attr_rel = table_open(AttributeRelationId, RowExclusiveLock);
 
    tuple = SearchSysCacheCopy2(ATTNUM,
                                ObjectIdGetDatum(relid),
                                Int16GetDatum(attnum));
    if (!HeapTupleIsValid(tuple))   /* shouldn't happen */
        elog(ERROR, "cache lookup failed for attribute %d of relation %u",
             attnum, relid);
    attStruct = (Form_pg_attribute) GETSTRUCT(tuple);
 
    /* Mark the attribute as dropped */
    attStruct->attisdropped = true;
 
    /*
     * Set the type OID to invalid.  A dropped attribute's type link cannot be
     * relied on (once the attribute is dropped, the type might be too).
     * Fortunately we do not need the type row --- the only really essential
     * information is the type's typlen and typalign, which are preserved in
     * the attribute's attlen and attalign.  We set atttypid to zero here as a
     * means of catching code that incorrectly expects it to be valid.
     */
    attStruct->atttypid = InvalidOid;
 
    /* Remove any not-null constraint the column may have */
    attStruct->attnotnull = false;
 
    /* Unset this so no one tries to look up the generation expression */
    attStruct->attgenerated = '\0';
 
    /*
     * Change the column name to something that isn't likely to conflict
     */
    snprintf(newattname, sizeof(newattname),
             "........pg.dropped.%d........", attnum);
    namestrcpy(&(attStruct->attname), newattname);
 
    /* Clear the missing value */
    attStruct->atthasmissing = false;
    nullsAtt[Anum_pg_attribute_attmissingval - 1] = true;
    replacesAtt[Anum_pg_attribute_attmissingval - 1] = true;
 
    /*
     * Clear the other nullable fields.  This saves some space in pg_attribute
     * and removes no longer useful information.
     */
    nullsAtt[Anum_pg_attribute_attstattarget - 1] = true;
    replacesAtt[Anum_pg_attribute_attstattarget - 1] = true;
    nullsAtt[Anum_pg_attribute_attacl - 1] = true;
    replacesAtt[Anum_pg_attribute_attacl - 1] = true;
    nullsAtt[Anum_pg_attribute_attoptions - 1] = true;
    replacesAtt[Anum_pg_attribute_attoptions - 1] = true;
    nullsAtt[Anum_pg_attribute_attfdwoptions - 1] = true;
    replacesAtt[Anum_pg_attribute_attfdwoptions - 1] = true;
 
    tuple = heap_modify_tuple(tuple, RelationGetDescr(attr_rel),
                              valuesAtt, nullsAtt, replacesAtt);
 
    CatalogTupleUpdate(attr_rel, &tuple->t_self, tuple);
 
    /*
     * Because updating the pg_attribute row will trigger a relcache flush for
     * the target relation, we need not do anything else to notify other
     * backends of the change.
     */
 
    table_close(attr_rel, RowExclusiveLock);
 
    RemoveStatistics(relid, attnum);
 
    relation_close(rel, NoLock);
}
 
/*
 * heap_drop_with_catalog   - removes specified relation from catalogs
 *
 * Note that this routine is not responsible for dropping objects that are
 * linked to the pg_class entry via dependencies (for example, indexes and
 * constraints).  Those are deleted by the dependency-tracing logic in
 * dependency.c before control gets here.  In general, therefore, this routine
 * should never be called directly; go through performDeletion() instead.
 */
void
heap_drop_with_catalog(Oid relid)
{
    Relation    rel;
    HeapTuple   tuple;
    Oid         parentOid = InvalidOid,
                defaultPartOid = InvalidOid;
 
    /*
     * To drop a partition safely, we must grab exclusive lock on its parent,
     * because another backend might be about to execute a query on the parent
     * table.  If it relies on previously cached partition descriptor, then it
     * could attempt to access the just-dropped relation as its partition. We
     * must therefore take a table lock strong enough to prevent all queries
     * on the table from proceeding until we commit and send out a
     * shared-cache-inval notice that will make them update their partition
     * descriptors.
     */
    tuple = SearchSysCache1(RELOID, ObjectIdGetDatum(relid));
    if (!HeapTupleIsValid(tuple))
        elog(ERROR, "cache lookup failed for relation %u", relid);
    if (((Form_pg_class) GETSTRUCT(tuple))->relispartition)
    {
        /*
         * We have to lock the parent if the partition is being detached,
         * because it's possible that some query still has a partition
         * descriptor that includes this partition.
         */
        parentOid = get_partition_parent(relid, true);
        LockRelationOid(parentOid, AccessExclusiveLock);
 
        /*
         * If this is not the default partition, dropping it will change the
         * default partition's partition constraint, so we must lock it.
         */
        defaultPartOid = get_default_partition_oid(parentOid);
        if (OidIsValid(defaultPartOid) && relid != defaultPartOid)
            LockRelationOid(defaultPartOid, AccessExclusiveLock);
    }
 
    ReleaseSysCache(tuple);
 
    /*
     * Open and lock the relation.
     */
    rel = relation_open(relid, AccessExclusiveLock);
 
    /*
     * There can no longer be anyone *else* touching the relation, but we
     * might still have open queries or cursors, or pending trigger events, in
     * our own session.
     */
    CheckTableNotInUse(rel, "DROP TABLE");
 
    /*
     * This effectively deletes all rows in the table, and may be done in a
     * serializable transaction.  In that case we must record a rw-conflict in
     * to this transaction from each transaction holding a predicate lock on
     * the table.
     */
    CheckTableForSerializableConflictIn(rel);
 
    /*
     * Delete pg_foreign_table tuple first.
     */
    if (rel->rd_rel->relkind == RELKIND_FOREIGN_TABLE)
    {
        Relation    ftrel;
        HeapTuple   fttuple;
 
        ftrel = table_open(ForeignTableRelationId, RowExclusiveLock);
 
        fttuple = SearchSysCache1(FOREIGNTABLEREL, ObjectIdGetDatum(relid));
        if (!HeapTupleIsValid(fttuple))
            elog(ERROR, "cache lookup failed for foreign table %u", relid);
 
        CatalogTupleDelete(ftrel, &fttuple->t_self);
 
        ReleaseSysCache(fttuple);
        table_close(ftrel, RowExclusiveLock);
    }
 
    /*
     * If a partitioned table, delete the pg_partitioned_table tuple.
     */
    if (rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
        RemovePartitionKeyByRelId(relid);
 
    /*
     * If the relation being dropped is the default partition itself,
     * invalidate its entry in pg_partitioned_table.
     */
    if (relid == defaultPartOid)
        update_default_partition_oid(parentOid, InvalidOid);
 
    /*
     * Schedule unlinking of the relation's physical files at commit.
     */
    if (RELKIND_HAS_STORAGE(rel->rd_rel->relkind))
        RelationDropStorage(rel);
 
    /* ensure that stats are dropped if transaction commits */
    pgstat_drop_relation(rel);
 
    /*
     * Close relcache entry, but *keep* AccessExclusiveLock on the relation
     * until transaction commit.  This ensures no one else will try to do
     * something with the doomed relation.
     */
    relation_close(rel, NoLock);
 
    /*
     * Remove any associated relation synchronization states.
     */
    RemoveSubscriptionRel(InvalidOid, relid);
 
    /*
     * Forget any ON COMMIT action for the rel
     */
    remove_on_commit_action(relid);
 
    /*
     * Flush the relation from the relcache.  We want to do this before
     * starting to remove catalog entries, just to be certain that no relcache
     * entry rebuild will happen partway through.  (That should not really
     * matter, since we don't do CommandCounterIncrement here, but let's be
     * safe.)
     */
    RelationForgetRelation(relid);
 
    /*
     * remove inheritance information
     */
    RelationRemoveInheritance(relid);
 
    /*
     * delete statistics
     */
    RemoveStatistics(relid, 0);
 
    /*
     * delete attribute tuples
     */
    DeleteAttributeTuples(relid);
 
    /*
     * delete relation tuple
     */
    DeleteRelationTuple(relid);
 
    if (OidIsValid(parentOid))
    {
        /*
         * If this is not the default partition, the partition constraint of
         * the default partition has changed to include the portion of the key
         * space previously covered by the dropped partition.
         */
        if (OidIsValid(defaultPartOid) && relid != defaultPartOid)
            CacheInvalidateRelcacheByRelid(defaultPartOid);
 
        /*
         * Invalidate the parent's relcache so that the partition is no longer
         * included in its partition descriptor.
         */
        CacheInvalidateRelcacheByRelid(parentOid);
        /* keep the lock */
    }
}
 
 
/*
 * RelationClearMissing
 *
 * Set atthasmissing and attmissingval to false/null for all attributes
 * where they are currently set. This can be safely and usefully done if
 * the table is rewritten (e.g. by VACUUM FULL or CLUSTER) where we know there
 * are no rows left with less than a full complement of attributes.
 *
 * The caller must have an AccessExclusive lock on the relation.
 */
void
RelationClearMissing(Relation rel)
{
    Relation    attr_rel;
    Oid         relid = RelationGetRelid(rel);
    int         natts = RelationGetNumberOfAttributes(rel);
    int         attnum;
    Datum       repl_val[Natts_pg_attribute];
    bool        repl_null[Natts_pg_attribute];
    bool        repl_repl[Natts_pg_attribute];
    Form_pg_attribute attrtuple;
    HeapTuple   tuple,
                newtuple;
 
    memset(repl_val, 0, sizeof(repl_val));
    memset(repl_null, false, sizeof(repl_null));
    memset(repl_repl, false, sizeof(repl_repl));
 
    repl_val[Anum_pg_attribute_atthasmissing - 1] = BoolGetDatum(false);
    repl_null[Anum_pg_attribute_attmissingval - 1] = true;
 
    repl_repl[Anum_pg_attribute_atthasmissing - 1] = true;
    repl_repl[Anum_pg_attribute_attmissingval - 1] = true;
 
 
    /* Get a lock on pg_attribute */
    attr_rel = table_open(AttributeRelationId, RowExclusiveLock);
 
    /* process each non-system attribute, including any dropped columns */
    for (attnum = 1; attnum <= natts; attnum++)
    {
        tuple = SearchSysCache2(ATTNUM,
                                ObjectIdGetDatum(relid),
                                Int16GetDatum(attnum));
        if (!HeapTupleIsValid(tuple))   /* shouldn't happen */
            elog(ERROR, "cache lookup failed for attribute %d of relation %u",
                 attnum, relid);
 
        attrtuple = (Form_pg_attribute) GETSTRUCT(tuple);
 
        /* ignore any where atthasmissing is not true */
        if (attrtuple->atthasmissing)
        {
            newtuple = heap_modify_tuple(tuple, RelationGetDescr(attr_rel),
                                         repl_val, repl_null, repl_repl);
 
            CatalogTupleUpdate(attr_rel, &newtuple->t_self, newtuple);
 
            heap_freetuple(newtuple);
        }
 
        ReleaseSysCache(tuple);
    }
 
    /*
     * Our update of the pg_attribute rows will force a relcache rebuild, so
     * there's nothing else to do here.
     */
    table_close(attr_rel, RowExclusiveLock);
}
 
/*
 * StoreAttrMissingVal
 *
 * Set the missing value of a single attribute.
 */
void
StoreAttrMissingVal(Relation rel, AttrNumber attnum, Datum missingval)
{
    Datum       valuesAtt[Natts_pg_attribute] = {0};
    bool        nullsAtt[Natts_pg_attribute] = {0};
    bool        replacesAtt[Natts_pg_attribute] = {0};
    Relation    attrrel;
    Form_pg_attribute attStruct;
    HeapTuple   atttup,
                newtup;
 
    /* This is only supported for plain tables */
    Assert(rel->rd_rel->relkind == RELKIND_RELATION);
 
    /* Fetch the pg_attribute row */
    attrrel = table_open(AttributeRelationId, RowExclusiveLock);
 
    atttup = SearchSysCache2(ATTNUM,
                             ObjectIdGetDatum(RelationGetRelid(rel)),
                             Int16GetDatum(attnum));
    if (!HeapTupleIsValid(atttup))  /* shouldn't happen */
        elog(ERROR, "cache lookup failed for attribute %d of relation %u",
             attnum, RelationGetRelid(rel));
    attStruct = (Form_pg_attribute) GETSTRUCT(atttup);
 
    /* Make a one-element array containing the value */
    missingval = PointerGetDatum(construct_array(&missingval,
                                                 1,
                                                 attStruct->atttypid,
                                                 attStruct->attlen,
                                                 attStruct->attbyval,
                                                 attStruct->attalign));
 
    /* Update the pg_attribute row */
    valuesAtt[Anum_pg_attribute_atthasmissing - 1] = BoolGetDatum(true);
    replacesAtt[Anum_pg_attribute_atthasmissing - 1] = true;
 
    valuesAtt[Anum_pg_attribute_attmissingval - 1] = missingval;
    replacesAtt[Anum_pg_attribute_attmissingval - 1] = true;
 
    newtup = heap_modify_tuple(atttup, RelationGetDescr(attrrel),
                               valuesAtt, nullsAtt, replacesAtt);
    CatalogTupleUpdate(attrrel, &newtup->t_self, newtup);
 
    /* clean up */
    ReleaseSysCache(atttup);
    table_close(attrrel, RowExclusiveLock);
}
 
/*
 * SetAttrMissing
 *
 * Set the missing value of a single attribute. This should only be used by
 * binary upgrade. Takes an AccessExclusive lock on the relation owning the
 * attribute.
 */
void
SetAttrMissing(Oid relid, char *attname, char *value)
{
    Datum       valuesAtt[Natts_pg_attribute] = {0};
    bool        nullsAtt[Natts_pg_attribute] = {0};
    bool        replacesAtt[Natts_pg_attribute] = {0};
    Datum       missingval;
    Form_pg_attribute attStruct;
    Relation    attrrel,
                tablerel;
    HeapTuple   atttup,
                newtup;
 
    /* lock the table the attribute belongs to */
    tablerel = table_open(relid, AccessExclusiveLock);
 
    /* Don't do anything unless it's a plain table */
    if (tablerel->rd_rel->relkind != RELKIND_RELATION)
    {
        table_close(tablerel, AccessExclusiveLock);
        return;
    }
 
    /* Lock the attribute row and get the data */
    attrrel = table_open(AttributeRelationId, RowExclusiveLock);
    atttup = SearchSysCacheAttName(relid, attname);
    if (!HeapTupleIsValid(atttup))
        elog(ERROR, "cache lookup failed for attribute %s of relation %u",
             attname, relid);
    attStruct = (Form_pg_attribute) GETSTRUCT(atttup);
 
    /* get an array value from the value string */
    missingval = OidFunctionCall3(F_ARRAY_IN,
                                  CStringGetDatum(value),
                                  ObjectIdGetDatum(attStruct->atttypid),
                                  Int32GetDatum(attStruct->atttypmod));
 
    /* update the tuple - set atthasmissing and attmissingval */
    valuesAtt[Anum_pg_attribute_atthasmissing - 1] = BoolGetDatum(true);
    replacesAtt[Anum_pg_attribute_atthasmissing - 1] = true;
    valuesAtt[Anum_pg_attribute_attmissingval - 1] = missingval;
    replacesAtt[Anum_pg_attribute_attmissingval - 1] = true;
 
    newtup = heap_modify_tuple(atttup, RelationGetDescr(attrrel),
                               valuesAtt, nullsAtt, replacesAtt);
    CatalogTupleUpdate(attrrel, &newtup->t_self, newtup);
 
    /* clean up */
    ReleaseSysCache(atttup);
    table_close(attrrel, RowExclusiveLock);
    table_close(tablerel, AccessExclusiveLock);
}
 
/*
 * Store a check-constraint expression for the given relation.
 *
 * Caller is responsible for updating the count of constraints
 * in the pg_class entry for the relation.
 *
 * The OID of the new constraint is returned.
 */
static Oid
StoreRelCheck(Relation rel, const char *ccname, Node *expr,
              bool is_enforced, bool is_validated, bool is_local,
              int16 inhcount, bool is_no_inherit, bool is_internal)
{
    char       *ccbin;
    List       *varList;
    int         keycount;
    int16      *attNos;
    Oid         constrOid;
 
    /*
     * Flatten expression to string form for storage.
     */
    ccbin = nodeToString(expr);
 
    /*
     * Find columns of rel that are used in expr
     *
     * NB: pull_var_clause is okay here only because we don't allow subselects
     * in check constraints; it would fail to examine the contents of
     * subselects.
     */
    varList = pull_var_clause(expr, 0);
    keycount = list_length(varList);
 
    if (keycount > 0)
    {
        ListCell   *vl;
        int         i = 0;
 
        attNos = (int16 *) palloc(keycount * sizeof(int16));
        foreach(vl, varList)
        {
            Var        *var = (Var *) lfirst(vl);
            int         j;
 
            for (j = 0; j < i; j++)
                if (attNos[j] == var->varattno)
                    break;
            if (j == i)
                attNos[i++] = var->varattno;
        }
        keycount = i;
    }
    else
        attNos = NULL;
 
    /*
     * Partitioned tables do not contain any rows themselves, so a NO INHERIT
     * constraint makes no sense.
     */
    if (is_no_inherit &&
        rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
        ereport(ERROR,
                (errcode(ERRCODE_INVALID_TABLE_DEFINITION),
                 errmsg("cannot add NO INHERIT constraint to partitioned table \"%s\"",
                        RelationGetRelationName(rel))));
 
    /*
     * Create the Check Constraint
     */
    constrOid =
        CreateConstraintEntry(ccname,   /* Constraint Name */
                              RelationGetNamespace(rel),    /* namespace */
                              CONSTRAINT_CHECK, /* Constraint Type */
                              false,    /* Is Deferrable */
                              false,    /* Is Deferred */
                              is_enforced,  /* Is Enforced */
                              is_validated,
                              InvalidOid,   /* no parent constraint */
                              RelationGetRelid(rel),    /* relation */
                              attNos,   /* attrs in the constraint */
                              keycount, /* # key attrs in the constraint */
                              keycount, /* # total attrs in the constraint */
                              InvalidOid,   /* not a domain constraint */
                              InvalidOid,   /* no associated index */
                              InvalidOid,   /* Foreign key fields */
                              NULL,
                              NULL,
                              NULL,
                              NULL,
                              0,
                              ' ',
                              ' ',
                              NULL,
                              0,
                              ' ',
                              NULL, /* not an exclusion constraint */
                              expr, /* Tree form of check constraint */
                              ccbin,    /* Binary form of check constraint */
                              is_local, /* conislocal */
                              inhcount, /* coninhcount */
                              is_no_inherit,    /* connoinherit */
                              false,    /* conperiod */
                              is_internal); /* internally constructed? */
 
    pfree(ccbin);
 
    return constrOid;
}
 
/*
 * Store a not-null constraint for the given relation
 *
 * The OID of the new constraint is returned.
 */
static Oid
StoreRelNotNull(Relation rel, const char *nnname, AttrNumber attnum,
                bool is_validated, bool is_local, int inhcount,
                bool is_no_inherit)
{
    Oid         constrOid;
 
    Assert(attnum > InvalidAttrNumber);
 
    constrOid =
        CreateConstraintEntry(nnname,
                              RelationGetNamespace(rel),
                              CONSTRAINT_NOTNULL,
                              false,
                              false,
                              true, /* Is Enforced */
                              is_validated,
                              InvalidOid,
                              RelationGetRelid(rel),
                              &attnum,
                              1,
                              1,
                              InvalidOid,   /* not a domain constraint */
                              InvalidOid,   /* no associated index */
                              InvalidOid,   /* Foreign key fields */
                              NULL,
                              NULL,
                              NULL,
                              NULL,
                              0,
                              ' ',
                              ' ',
                              NULL,
                              0,
                              ' ',
                              NULL, /* not an exclusion constraint */
                              NULL,
                              NULL,
                              is_local,
                              inhcount,
                              is_no_inherit,
                              false,
                              false);
    return constrOid;
}
 
/*
 * Store defaults and CHECK constraints (passed as a list of CookedConstraint).
 *
 * Each CookedConstraint struct is modified to store the new catalog tuple OID.
 *
 * NOTE: only pre-cooked expressions will be passed this way, which is to
 * say expressions inherited from an existing relation.  Newly parsed
 * expressions can be added later, by direct calls to StoreAttrDefault
 * and StoreRelCheck (see AddRelationNewConstraints()).
 */
static void
StoreConstraints(Relation rel, List *cooked_constraints, bool is_internal)
{
    int         numchecks = 0;
    ListCell   *lc;
 
    if (cooked_constraints == NIL)
        return;                 /* nothing to do */
 
    /*
     * Deparsing of constraint expressions will fail unless the just-created
     * pg_attribute tuples for this relation are made visible.  So, bump the
     * command counter.  CAUTION: this will cause a relcache entry rebuild.
     */
    CommandCounterIncrement();
 
    foreach(lc, cooked_constraints)
    {
        CookedConstraint *con = (CookedConstraint *) lfirst(lc);
 
        switch (con->contype)
        {
            case CONSTR_DEFAULT:
                con->conoid = StoreAttrDefault(rel, con->attnum, con->expr,
                                               is_internal);
                break;
            case CONSTR_CHECK:
                con->conoid =
                    StoreRelCheck(rel, con->name, con->expr,
                                  con->is_enforced, !con->skip_validation,
                                  con->is_local, con->inhcount,
                                  con->is_no_inherit, is_internal);
                numchecks++;
                break;
 
            default:
                elog(ERROR, "unrecognized constraint type: %d",
                     (int) con->contype);
        }
    }
 
    if (numchecks > 0)
        SetRelationNumChecks(rel, numchecks);
}
 
/*
 * AddRelationNewConstraints
 *
 * Add new column default expressions and/or constraint check expressions
 * to an existing relation.  This is defined to do both for efficiency in
 * DefineRelation, but of course you can do just one or the other by passing
 * empty lists.
 *
 * rel: relation to be modified
 * newColDefaults: list of RawColumnDefault structures
 * newConstraints: list of Constraint nodes
 * allow_merge: true if check constraints may be merged with existing ones
 * is_local: true if definition is local, false if it's inherited
 * is_internal: true if result of some internal process, not a user request
 * queryString: used during expression transformation of default values and
 *      cooked CHECK constraints
 *
 * All entries in newColDefaults will be processed.  Entries in newConstraints
 * will be processed only if they are CONSTR_CHECK or CONSTR_NOTNULL types.
 *
 * Returns a list of CookedConstraint nodes that shows the cooked form of
 * the default and constraint expressions added to the relation.
 *
 * NB: caller should have opened rel with some self-conflicting lock mode,
 * and should hold that lock till end of transaction; for normal cases that'll
 * be AccessExclusiveLock, but if caller knows that the constraint is already
 * enforced by some other means, it can be ShareUpdateExclusiveLock.  Also, we
 * assume the caller has done a CommandCounterIncrement if necessary to make
 * the relation's catalog tuples visible.
 */
List *
AddRelationNewConstraints(Relation rel,
                          List *newColDefaults,
                          List *newConstraints,
                          bool allow_merge,
                          bool is_local,
                          bool is_internal,
                          const char *queryString)
{
    List       *cookedConstraints = NIL;
    TupleDesc   tupleDesc;
    TupleConstr *oldconstr;
    int         numoldchecks;
    ParseState *pstate;
    ParseNamespaceItem *nsitem;
    int         numchecks;
    List       *checknames;
    List       *nnnames;
    Node       *expr;
    CookedConstraint *cooked;
 
    /*
     * Get info about existing constraints.
     */
    tupleDesc = RelationGetDescr(rel);
    oldconstr = tupleDesc->constr;
    if (oldconstr)
        numoldchecks = oldconstr->num_check;
    else
        numoldchecks = 0;
 
    /*
     * Create a dummy ParseState and insert the target relation as its sole
     * rangetable entry.  We need a ParseState for transformExpr.
     */
    pstate = make_parsestate(NULL);
    pstate->p_sourcetext = queryString;
    nsitem = addRangeTableEntryForRelation(pstate,
                                           rel,
                                           AccessShareLock,
                                           NULL,
                                           false,
                                           true);
    addNSItemToQuery(pstate, nsitem, true, true, true);
 
    /*
     * Process column default expressions.
     */
    foreach_ptr(RawColumnDefault, colDef, newColDefaults)
    {
        Form_pg_attribute atp = TupleDescAttr(rel->rd_att, colDef->attnum - 1);
        Oid         defOid;
 
        expr = cookDefault(pstate, colDef->raw_default,
                           atp->atttypid, atp->atttypmod,
                           NameStr(atp->attname),
                           atp->attgenerated);
 
        /*
         * If the expression is just a NULL constant, we do not bother to make
         * an explicit pg_attrdef entry, since the default behavior is
         * equivalent.  This applies to column defaults, but not for
         * generation expressions.
         *
         * Note a nonobvious property of this test: if the column is of a
         * domain type, what we'll get is not a bare null Const but a
         * CoerceToDomain expr, so we will not discard the default.  This is
         * critical because the column default needs to be retained to
         * override any default that the domain might have.
         */
        if (expr == NULL ||
            (!colDef->generated &&
             IsA(expr, Const) &&
             castNode(Const, expr)->constisnull))
            continue;
 
        defOid = StoreAttrDefault(rel, colDef->attnum, expr, is_internal);
 
        cooked = palloc_object(CookedConstraint);
        cooked->contype = CONSTR_DEFAULT;
        cooked->conoid = defOid;
        cooked->name = NULL;
        cooked->attnum = colDef->attnum;
        cooked->expr = expr;
        cooked->is_enforced = true;
        cooked->skip_validation = false;
        cooked->is_local = is_local;
        cooked->inhcount = is_local ? 0 : 1;
        cooked->is_no_inherit = false;
        cookedConstraints = lappend(cookedConstraints, cooked);
    }
 
    /*
     * Process constraint expressions.
     */
    numchecks = numoldchecks;
    checknames = NIL;
    nnnames = NIL;
    foreach_node(Constraint, cdef, newConstraints)
    {
        Oid         constrOid;
 
        if (cdef->contype == CONSTR_CHECK)
        {
            char       *ccname;
 
            if (cdef->raw_expr != NULL)
            {
                Assert(cdef->cooked_expr == NULL);
 
                /*
                 * Transform raw parsetree to executable expression, and
                 * verify it's valid as a CHECK constraint.
                 */
                expr = cookConstraint(pstate, cdef->raw_expr,
                                      RelationGetRelationName(rel));
            }
            else
            {
                Assert(cdef->cooked_expr != NULL);
 
                /*
                 * Here, we assume the parser will only pass us valid CHECK
                 * expressions, so we do no particular checking.
                 */
                expr = stringToNode(cdef->cooked_expr);
            }
 
            /*
             * Check name uniqueness, or generate a name if none was given.
             */
            if (cdef->conname != NULL)
            {
                ccname = cdef->conname;
                /* Check against other new constraints */
                /* Needed because we don't do CommandCounterIncrement in loop */
                foreach_ptr(char, chkname, checknames)
                {
                    if (strcmp(chkname, ccname) == 0)
                        ereport(ERROR,
                                (errcode(ERRCODE_DUPLICATE_OBJECT),
                                 errmsg("check constraint \"%s\" already exists",
                                        ccname)));
                }
 
                /* save name for future checks */
                checknames = lappend(checknames, ccname);
 
                /*
                 * Check against pre-existing constraints.  If we are allowed
                 * to merge with an existing constraint, there's no more to do
                 * here. (We omit the duplicate constraint from the result,
                 * which is what ATAddCheckNNConstraint wants.)
                 */
                if (MergeWithExistingConstraint(rel, ccname, expr,
                                                allow_merge, is_local,
                                                cdef->is_enforced,
                                                cdef->initially_valid,
                                                cdef->is_no_inherit))
                    continue;
            }
            else
            {
                /*
                 * When generating a name, we want to create "tab_col_check"
                 * for a column constraint and "tab_check" for a table
                 * constraint.  We no longer have any info about the syntactic
                 * positioning of the constraint phrase, so we approximate
                 * this by seeing whether the expression references more than
                 * one column.  (If the user played by the rules, the result
                 * is the same...)
                 *
                 * Note: pull_var_clause() doesn't descend into sublinks, but
                 * we eliminated those above; and anyway this only needs to be
                 * an approximate answer.
                 */
                List       *vars;
                char       *colname;
 
                vars = pull_var_clause(expr, 0);
 
                /* eliminate duplicates */
                vars = list_union(NIL, vars);
 
                if (list_length(vars) == 1)
                    colname = get_attname(RelationGetRelid(rel),
                                          ((Var *) linitial(vars))->varattno,
                                          true);
                else
                    colname = NULL;
 
                ccname = ChooseConstraintName(RelationGetRelationName(rel),
                                              colname,
                                              "check",
                                              RelationGetNamespace(rel),
                                              checknames);
 
                /* save name for future checks */
                checknames = lappend(checknames, ccname);
            }
 
            /*
             * OK, store it.
             */
            constrOid =
                StoreRelCheck(rel, ccname, expr, cdef->is_enforced,
                              cdef->initially_valid, is_local,
                              is_local ? 0 : 1, cdef->is_no_inherit,
                              is_internal);
 
            numchecks++;
 
            cooked = palloc_object(CookedConstraint);
            cooked->contype = CONSTR_CHECK;
            cooked->conoid = constrOid;
            cooked->name = ccname;
            cooked->attnum = 0;
            cooked->expr = expr;
            cooked->is_enforced = cdef->is_enforced;
            cooked->skip_validation = cdef->skip_validation;
            cooked->is_local = is_local;
            cooked->inhcount = is_local ? 0 : 1;
            cooked->is_no_inherit = cdef->is_no_inherit;
            cookedConstraints = lappend(cookedConstraints, cooked);
        }
        else if (cdef->contype == CONSTR_NOTNULL)
        {
            CookedConstraint *nncooked;
            AttrNumber  colnum;
            int16       inhcount = is_local ? 0 : 1;
            char       *nnname;
 
            /* Determine which column to modify */
            colnum = get_attnum(RelationGetRelid(rel), strVal(linitial(cdef->keys)));
            if (colnum == InvalidAttrNumber)
                ereport(ERROR,
                        errcode(ERRCODE_UNDEFINED_COLUMN),
                        errmsg("column \"%s\" of relation \"%s\" does not exist",
                               strVal(linitial(cdef->keys)), RelationGetRelationName(rel)));
            if (colnum < InvalidAttrNumber)
                ereport(ERROR,
                        errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
                        errmsg("cannot add not-null constraint on system column \"%s\"",
                               strVal(linitial(cdef->keys))));
 
            Assert(cdef->initially_valid != cdef->skip_validation);
 
            /*
             * If the column already has a not-null constraint, we don't want
             * to add another one; adjust inheritance status as needed.  This
             * also checks whether the existing constraint matches the
             * requested validity.
             */
            if (AdjustNotNullInheritance(RelationGetRelid(rel), colnum,
                                         cdef->conname,
                                         is_local, cdef->is_no_inherit,
                                         cdef->skip_validation))
                continue;
 
            /*
             * If a constraint name is specified, check that it isn't already
             * used.  Otherwise, choose a non-conflicting one ourselves.
             */
            if (cdef->conname)
            {
                if (ConstraintNameIsUsed(CONSTRAINT_RELATION,
                                         RelationGetRelid(rel),
                                         cdef->conname))
                    ereport(ERROR,
                            errcode(ERRCODE_DUPLICATE_OBJECT),
                            errmsg("constraint \"%s\" for relation \"%s\" already exists",
                                   cdef->conname, RelationGetRelationName(rel)));
                nnname = cdef->conname;
            }
            else
                nnname = ChooseConstraintName(RelationGetRelationName(rel),
                                              strVal(linitial(cdef->keys)),
                                              "not_null",
                                              RelationGetNamespace(rel),
                                              nnnames);
            nnnames = lappend(nnnames, nnname);
 
            constrOid =
                StoreRelNotNull(rel, nnname, colnum,
                                cdef->initially_valid,
                                is_local,
                                inhcount,
                                cdef->is_no_inherit);
 
            nncooked = palloc_object(CookedConstraint);
            nncooked->contype = CONSTR_NOTNULL;
            nncooked->conoid = constrOid;
            nncooked->name = nnname;
            nncooked->attnum = colnum;
            nncooked->expr = NULL;
            nncooked->is_enforced = true;
            nncooked->skip_validation = cdef->skip_validation;
            nncooked->is_local = is_local;
            nncooked->inhcount = inhcount;
            nncooked->is_no_inherit = cdef->is_no_inherit;
 
            cookedConstraints = lappend(cookedConstraints, nncooked);
        }
    }
 
    /*
     * Update the count of constraints in the relation's pg_class tuple. We do
     * this even if there was no change, in order to ensure that an SI update
     * message is sent out for the pg_class tuple, which will force other
     * backends to rebuild their relcache entries for the rel. (This is
     * critical if we added defaults but not constraints.)
     */
    SetRelationNumChecks(rel, numchecks);
 
    return cookedConstraints;
}
 
/*
 * Check for a pre-existing check constraint that conflicts with a proposed
 * new one, and either adjust its conislocal/coninhcount settings or throw
 * error as needed.
 *
 * Returns true if merged (constraint is a duplicate), or false if it's
 * got a so-far-unique name, or throws error if conflict.
 *
 * XXX See MergeConstraintsIntoExisting too if you change this code.
 */
static bool
MergeWithExistingConstraint(Relation rel, const char *ccname, Node *expr,
                            bool allow_merge, bool is_local,
                            bool is_enforced,
                            bool is_initially_valid,
                            bool is_no_inherit)
{
    bool        found;
    Relation    conDesc;
    SysScanDesc conscan;
    ScanKeyData skey[3];
    HeapTuple   tup;
 
    /* Search for a pg_constraint entry with same name and relation */
    conDesc = table_open(ConstraintRelationId, RowExclusiveLock);
 
    found = false;
 
    ScanKeyInit(&skey[0],
                Anum_pg_constraint_conrelid,
                BTEqualStrategyNumber, F_OIDEQ,
                ObjectIdGetDatum(RelationGetRelid(rel)));
    ScanKeyInit(&skey[1],
                Anum_pg_constraint_contypid,
                BTEqualStrategyNumber, F_OIDEQ,
                ObjectIdGetDatum(InvalidOid));
    ScanKeyInit(&skey[2],
                Anum_pg_constraint_conname,
                BTEqualStrategyNumber, F_NAMEEQ,
                CStringGetDatum(ccname));
 
    conscan = systable_beginscan(conDesc, ConstraintRelidTypidNameIndexId, true,
                                 NULL, 3, skey);
 
    /* There can be at most one matching row */
    if (HeapTupleIsValid(tup = systable_getnext(conscan)))
    {
        Form_pg_constraint con = (Form_pg_constraint) GETSTRUCT(tup);
 
        /* Found it.  Conflicts if not identical check constraint */
        if (con->contype == CONSTRAINT_CHECK)
        {
            Datum       val;
            bool        isnull;
 
            val = fastgetattr(tup,
                              Anum_pg_constraint_conbin,
                              conDesc->rd_att, &isnull);
            if (isnull)
                elog(ERROR, "null conbin for rel %s",
                     RelationGetRelationName(rel));
            if (equal(expr, stringToNode(TextDatumGetCString(val))))
                found = true;
        }
 
        /*
         * If the existing constraint is purely inherited (no local
         * definition) then interpret addition of a local constraint as a
         * legal merge.  This allows ALTER ADD CONSTRAINT on parent and child
         * tables to be given in either order with same end state.  However if
         * the relation is a partition, all inherited constraints are always
         * non-local, including those that were merged.
         */
        if (is_local && !con->conislocal && !rel->rd_rel->relispartition)
            allow_merge = true;
 
        if (!found || !allow_merge)
            ereport(ERROR,
                    (errcode(ERRCODE_DUPLICATE_OBJECT),
                     errmsg("constraint \"%s\" for relation \"%s\" already exists",
                            ccname, RelationGetRelationName(rel))));
 
        /* If the child constraint is "no inherit" then cannot merge */
        if (con->connoinherit)
            ereport(ERROR,
                    (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
                     errmsg("constraint \"%s\" conflicts with non-inherited constraint on relation \"%s\"",
                            ccname, RelationGetRelationName(rel))));
 
        /*
         * Must not change an existing inherited constraint to "no inherit"
         * status.  That's because inherited constraints should be able to
         * propagate to lower-level children.
         */
        if (con->coninhcount > 0 && is_no_inherit)
            ereport(ERROR,
                    (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
                     errmsg("constraint \"%s\" conflicts with inherited constraint on relation \"%s\"",
                            ccname, RelationGetRelationName(rel))));
 
        /*
         * If the child constraint is "not valid" then cannot merge with a
         * valid parent constraint.
         */
        if (is_initially_valid && con->conenforced && !con->convalidated)
            ereport(ERROR,
                    (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
                     errmsg("constraint \"%s\" conflicts with NOT VALID constraint on relation \"%s\"",
                            ccname, RelationGetRelationName(rel))));
 
        /*
         * A non-enforced child constraint cannot be merged with an enforced
         * parent constraint. However, the reverse is allowed, where the child
         * constraint is enforced.
         */
        if ((!is_local && is_enforced && !con->conenforced) ||
            (is_local && !is_enforced && con->conenforced))
            ereport(ERROR,
                    (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
                     errmsg("constraint \"%s\" conflicts with NOT ENFORCED constraint on relation \"%s\"",
                            ccname, RelationGetRelationName(rel))));
 
        /* OK to update the tuple */
        ereport(NOTICE,
                (errmsg("merging constraint \"%s\" with inherited definition",
                        ccname)));
 
        tup = heap_copytuple(tup);
        con = (Form_pg_constraint) GETSTRUCT(tup);
 
        /*
         * In case of partitions, an inherited constraint must be inherited
         * only once since it cannot have multiple parents and it is never
         * considered local.
         */
        if (rel->rd_rel->relispartition)
        {
            con->coninhcount = 1;
            con->conislocal = false;
        }
        else
        {
            if (is_local)
                con->conislocal = true;
            else if (pg_add_s16_overflow(con->coninhcount, 1,
                                         &con->coninhcount))
                ereport(ERROR,
                        errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
                        errmsg("too many inheritance parents"));
        }
 
        if (is_no_inherit)
        {
            Assert(is_local);
            con->connoinherit = true;
        }
 
        /*
         * If the child constraint is required to be enforced while the parent
         * constraint is not, this should be allowed by marking the child
         * constraint as enforced. In the reverse case, an error would have
         * already been thrown before reaching this point.
         */
        if (is_enforced && !con->conenforced)
        {
            Assert(is_local);
            con->conenforced = true;
            con->convalidated = true;
        }
 
        CatalogTupleUpdate(conDesc, &tup->t_self, tup);
    }
 
    systable_endscan(conscan);
    table_close(conDesc, RowExclusiveLock);
 
    return found;
}
 
/*
 * Create the not-null constraints when creating a new relation
 *
 * These come from two sources: the 'constraints' list (of Constraint) is
 * specified directly by the user; the 'old_notnulls' list (of
 * CookedConstraint) comes from inheritance.  We create one constraint
 * for each column, giving priority to user-specified ones, and setting
 * inhcount according to how many parents cause each column to get a
 * not-null constraint.  If a user-specified name clashes with another
 * user-specified name, an error is raised.  'existing_constraints'
 * is a list of already defined constraint names, which should be avoided
 * when generating further ones.
 *
 * Returns a list of AttrNumber for columns that need to have the attnotnull
 * flag set.
 */
List *
AddRelationNotNullConstraints(Relation rel, List *constraints,
                              List *old_notnulls, List *existing_constraints)
{
    List       *givennames;
    List       *nnnames;
    List       *nncols = NIL;
 
    /*
     * We track two lists of names: nnnames keeps all the constraint names,
     * givennames tracks user-generated names.  The distinction is important,
     * because we must raise error for user-generated name conflicts, but for
     * system-generated name conflicts we just generate another.
     */
    nnnames = list_copy(existing_constraints);  /* don't scribble on input */
    givennames = NIL;
 
    /*
     * First, create all not-null constraints that are directly specified by
     * the user.  Note that inheritance might have given us another source for
     * each, so we must scan the old_notnulls list and increment inhcount for
     * each element with identical attnum.  We delete from there any element
     * that we process.
     *
     * We don't use foreach() here because we have two nested loops over the
     * constraint list, with possible element deletions in the inner one. If
     * we used foreach_delete_current() it could only fix up the state of one
     * of the loops, so it seems cleaner to use looping over list indexes for
     * both loops.  Note that any deletion will happen beyond where the outer
     * loop is, so its index never needs adjustment.
     */
    for (int outerpos = 0; outerpos < list_length(constraints); outerpos++)
    {
        Constraint *constr;
        AttrNumber  attnum;
        char       *conname;
        int         inhcount = 0;
 
        constr = list_nth_node(Constraint, constraints, outerpos);
 
        Assert(constr->contype == CONSTR_NOTNULL);
 
        attnum = get_attnum(RelationGetRelid(rel),
                            strVal(linitial(constr->keys)));
        if (attnum == InvalidAttrNumber)
            ereport(ERROR,
                    errcode(ERRCODE_UNDEFINED_COLUMN),
                    errmsg("column \"%s\" of relation \"%s\" does not exist",
                           strVal(linitial(constr->keys)),
                           RelationGetRelationName(rel)));
        if (attnum < InvalidAttrNumber)
            ereport(ERROR,
                    errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
                    errmsg("cannot add not-null constraint on system column \"%s\"",
                           strVal(linitial(constr->keys))));
 
        /*
         * A column can only have one not-null constraint, so discard any
         * additional ones that appear for columns we already saw; but check
         * that the NO INHERIT flags match.
         */
        for (int restpos = outerpos + 1; restpos < list_length(constraints);)
        {
            Constraint *other;
 
            other = list_nth_node(Constraint, constraints, restpos);
            if (strcmp(strVal(linitial(constr->keys)),
                       strVal(linitial(other->keys))) == 0)
            {
                if (other->is_no_inherit != constr->is_no_inherit)
                    ereport(ERROR,
                            errcode(ERRCODE_SYNTAX_ERROR),
                            errmsg("conflicting NO INHERIT declaration for not-null constraint on column \"%s\"",
                                   strVal(linitial(constr->keys))));
 
                /*
                 * Preserve constraint name if one is specified, but raise an
                 * error if conflicting ones are specified.
                 */
                if (other->conname)
                {
                    if (!constr->conname)
                        constr->conname = pstrdup(other->conname);
                    else if (strcmp(constr->conname, other->conname) != 0)
                        ereport(ERROR,
                                errcode(ERRCODE_SYNTAX_ERROR),
                                errmsg("conflicting not-null constraint names \"%s\" and \"%s\"",
                                       constr->conname, other->conname));
                }
 
                /* XXX do we need to verify any other fields? */
                constraints = list_delete_nth_cell(constraints, restpos);
            }
            else
                restpos++;
        }
 
        /*
         * Search in the list of inherited constraints for any entries on the
         * same column; determine an inheritance count from that.  Also, if at
         * least one parent has a constraint for this column, then we must not
         * accept a user specification for a NO INHERIT one.  Any constraint
         * from parents that we process here is deleted from the list: we no
         * longer need to process it in the loop below.
         */
        foreach_ptr(CookedConstraint, old, old_notnulls)
        {
            if (old->attnum == attnum)
            {
                /*
                 * If we get a constraint from the parent, having a local NO
                 * INHERIT one doesn't work.
                 */
                if (constr->is_no_inherit)
                    ereport(ERROR,
                            (errcode(ERRCODE_DATATYPE_MISMATCH),
                             errmsg("cannot define not-null constraint with NO INHERIT on column \"%s\"",
                                    strVal(linitial(constr->keys))),
                             errdetail("The column has an inherited not-null constraint.")));
 
                inhcount++;
                old_notnulls = foreach_delete_current(old_notnulls, old);
            }
        }
 
        /*
         * Determine a constraint name, which may have been specified by the
         * user, or raise an error if a conflict exists with another
         * user-specified name.
         */
        if (constr->conname)
        {
            foreach_ptr(char, thisname, givennames)
            {
                if (strcmp(thisname, constr->conname) == 0)
                    ereport(ERROR,
                            errcode(ERRCODE_DUPLICATE_OBJECT),
                            errmsg("constraint \"%s\" for relation \"%s\" already exists",
                                   constr->conname,
                                   RelationGetRelationName(rel)));
            }
 
            conname = constr->conname;
            givennames = lappend(givennames, conname);
        }
        else
            conname = ChooseConstraintName(RelationGetRelationName(rel),
                                           get_attname(RelationGetRelid(rel),
                                                       attnum, false),
                                           "not_null",
                                           RelationGetNamespace(rel),
                                           nnnames);
        nnnames = lappend(nnnames, conname);
 
        StoreRelNotNull(rel, conname,
                        attnum, true, true,
                        inhcount, constr->is_no_inherit);
 
        nncols = lappend_int(nncols, attnum);
    }
 
    /*
     * If any column remains in the old_notnulls list, we must create a not-
     * null constraint marked not-local for that column.  Because multiple
     * parents could specify a not-null constraint for the same column, we
     * must count how many there are and set an appropriate inhcount
     * accordingly, deleting elements we've already processed.
     *
     * We don't use foreach() here because we have two nested loops over the
     * constraint list, with possible element deletions in the inner one. If
     * we used foreach_delete_current() it could only fix up the state of one
     * of the loops, so it seems cleaner to use looping over list indexes for
     * both loops.  Note that any deletion will happen beyond where the outer
     * loop is, so its index never needs adjustment.
     */
    for (int outerpos = 0; outerpos < list_length(old_notnulls); outerpos++)
    {
        CookedConstraint *cooked;
        char       *conname = NULL;
        int         inhcount = 1;
 
        cooked = (CookedConstraint *) list_nth(old_notnulls, outerpos);
        Assert(cooked->contype == CONSTR_NOTNULL);
        Assert(cooked->name);
 
        /*
         * Preserve the first non-conflicting constraint name we come across.
         */
        if (conname == NULL)
            conname = cooked->name;
 
        for (int restpos = outerpos + 1; restpos < list_length(old_notnulls);)
        {
            CookedConstraint *other;
 
            other = (CookedConstraint *) list_nth(old_notnulls, restpos);
            Assert(other->name);
            if (other->attnum == cooked->attnum)
            {
                if (conname == NULL)
                    conname = other->name;
 
                inhcount++;
                old_notnulls = list_delete_nth_cell(old_notnulls, restpos);
            }
            else
                restpos++;
        }
 
        /* If we got a name, make sure it isn't one we've already used */
        if (conname != NULL)
        {
            foreach_ptr(char, thisname, nnnames)
            {
                if (strcmp(thisname, conname) == 0)
                {
                    conname = NULL;
                    break;
                }
            }
        }
 
        /* and choose a name, if needed */
        if (conname == NULL)
            conname = ChooseConstraintName(RelationGetRelationName(rel),
                                           get_attname(RelationGetRelid(rel),
                                                       cooked->attnum, false),
                                           "not_null",
                                           RelationGetNamespace(rel),
                                           nnnames);
        nnnames = lappend(nnnames, conname);
 
        /* ignore the origin constraint's is_local and inhcount */
        StoreRelNotNull(rel, conname, cooked->attnum, true,
                        false, inhcount, false);
 
        nncols = lappend_int(nncols, cooked->attnum);
    }
 
    return nncols;
}
 
/*
 * Update the count of constraints in the relation's pg_class tuple.
 *
 * Caller had better hold exclusive lock on the relation.
 *
 * An important side effect is that a SI update message will be sent out for
 * the pg_class tuple, which will force other backends to rebuild their
 * relcache entries for the rel.  Also, this backend will rebuild its
 * own relcache entry at the next CommandCounterIncrement.
 */
static void
SetRelationNumChecks(Relation rel, int numchecks)
{
    Relation    relrel;
    HeapTuple   reltup;
    Form_pg_class relStruct;
 
    relrel = table_open(RelationRelationId, RowExclusiveLock);
    reltup = SearchSysCacheCopy1(RELOID,
                                 ObjectIdGetDatum(RelationGetRelid(rel)));
    if (!HeapTupleIsValid(reltup))
        elog(ERROR, "cache lookup failed for relation %u",
             RelationGetRelid(rel));
    relStruct = (Form_pg_class) GETSTRUCT(reltup);
 
    if (relStruct->relchecks != numchecks)
    {
        relStruct->relchecks = numchecks;
 
        CatalogTupleUpdate(relrel, &reltup->t_self, reltup);
    }
    else
    {
        /* Skip the disk update, but force relcache inval anyway */
        CacheInvalidateRelcache(rel);
    }
 
    heap_freetuple(reltup);
    table_close(relrel, RowExclusiveLock);
}
 
/*
 * Check for references to generated columns
 */
static bool
check_nested_generated_walker(Node *node, void *context)
{
    ParseState *pstate = context;
 
    if (node == NULL)
        return false;
    else if (IsA(node, Var))
    {
        Var        *var = (Var *) node;
        Oid         relid;
        AttrNumber  attnum;
 
        relid = rt_fetch(var->varno, pstate->p_rtable)->relid;
        if (!OidIsValid(relid))
            return false;       /* XXX shouldn't we raise an error? */
 
        attnum = var->varattno;
 
        if (attnum > 0 && get_attgenerated(relid, attnum))
            ereport(ERROR,
                    (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
                     errmsg("cannot use generated column \"%s\" in column generation expression",
                            get_attname(relid, attnum, false)),
                     errdetail("A generated column cannot reference another generated column."),
                     parser_errposition(pstate, var->location)));
        /* A whole-row Var is necessarily self-referential, so forbid it */
        if (attnum == 0)
            ereport(ERROR,
                    (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
                     errmsg("cannot use whole-row variable in column generation expression"),
                     errdetail("This would cause the generated column to depend on its own value."),
                     parser_errposition(pstate, var->location)));
        /* System columns were already checked in the parser */
 
        return false;
    }
    else
        return expression_tree_walker(node, check_nested_generated_walker,
                                      context);
}
 
static void
check_nested_generated(ParseState *pstate, Node *node)
{
    check_nested_generated_walker(node, pstate);
}
 
/*
 * Check security of virtual generated column expression.
 *
 * Just like selecting from a view is exploitable (CVE-2024-7348), selecting
 * from a table with virtual generated columns is exploitable.  Users who are
 * concerned about this can avoid selecting from views, but telling them to
 * avoid selecting from tables is less practical.
 *
 * To address this, this restricts generation expressions for virtual
 * generated columns are restricted to using built-in functions and types.  We
 * assume that built-in functions and types cannot be exploited for this
 * purpose.  Note the overall security also requires that all functions in use
 * a immutable.  (For example, there are some built-in non-immutable functions
 * that can run arbitrary SQL.)  The immutability is checked elsewhere, since
 * that is a property that needs to hold independent of security
 * considerations.
 *
 * In the future, this could be expanded by some new mechanism to declare
 * other functions and types as safe or trusted for this purpose, but that is
 * to be designed.
 */
 
/*
 * Callback for check_functions_in_node() that determines whether a function
 * is user-defined.
 */
static bool
contains_user_functions_checker(Oid func_id, void *context)
{
    return (func_id >= FirstUnpinnedObjectId);
}
 
/*
 * Checks for all the things we don't want in the generation expressions of
 * virtual generated columns for security reasons.  Errors out if it finds
 * one.
 */
static bool
check_virtual_generated_security_walker(Node *node, void *context)
{
    ParseState *pstate = context;
 
    if (node == NULL)
        return false;
 
    if (!IsA(node, List))
    {
        if (check_functions_in_node(node, contains_user_functions_checker, NULL))
            ereport(ERROR,
                    errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
                    errmsg("generation expression uses user-defined function"),
                    errdetail("Virtual generated columns that make use of user-defined functions are not yet supported."),
                    parser_errposition(pstate, exprLocation(node)));
 
        /*
         * check_functions_in_node() doesn't check some node types (see
         * comment there).  We handle CoerceToDomain and MinMaxExpr by
         * checking for built-in types.  The other listed node types cannot
         * call user-definable SQL-visible functions.
         *
         * We furthermore need this type check to handle built-in, immutable
         * polymorphic functions such as array_eq().
         */
        if (exprType(node) >= FirstUnpinnedObjectId)
            ereport(ERROR,
                    errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
                    errmsg("generation expression uses user-defined type"),
                    errdetail("Virtual generated columns that make use of user-defined types are not yet supported."),
                    parser_errposition(pstate, exprLocation(node)));
    }
 
    return expression_tree_walker(node, check_virtual_generated_security_walker, context);
}
 
static void
check_virtual_generated_security(ParseState *pstate, Node *node)
{
    check_virtual_generated_security_walker(node, pstate);
}
 
/*
 * Take a raw default and convert it to a cooked format ready for
 * storage.
 *
 * Parse state should be set up to recognize any vars that might appear
 * in the expression.  (Even though we plan to reject vars, it's more
 * user-friendly to give the correct error message than "unknown var".)
 *
 * If atttypid is not InvalidOid, coerce the expression to the specified
 * type (and typmod atttypmod).   attname is only needed in this case:
 * it is used in the error message, if any.
 */
Node *
cookDefault(ParseState *pstate,
            Node *raw_default,
            Oid atttypid,
            int32 atttypmod,
            const char *attname,
            char attgenerated)
{
    Node       *expr;
 
    Assert(raw_default != NULL);
 
    /*
     * Transform raw parsetree to executable expression.
     */
    expr = transformExpr(pstate, raw_default, attgenerated ? EXPR_KIND_GENERATED_COLUMN : EXPR_KIND_COLUMN_DEFAULT);
 
    if (attgenerated)
    {
        /* Disallow refs to other generated columns */
        check_nested_generated(pstate, expr);
 
        /* Disallow mutable functions */
        if (contain_mutable_functions_after_planning((Expr *) expr))
            ereport(ERROR,
                    (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
                     errmsg("generation expression is not immutable")));
 
        /* Check security of expressions for virtual generated column */
        if (attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
            check_virtual_generated_security(pstate, expr);
    }
    else
    {
        /*
         * For a default expression, transformExpr() should have rejected
         * column references.
         */
        Assert(!contain_var_clause(expr));
    }
 
    /*
     * Coerce the expression to the correct type and typmod, if given. This
     * should match the parser's processing of non-defaulted expressions ---
     * see transformAssignedExpr().
     */
    if (OidIsValid(atttypid))
    {
        Oid         type_id = exprType(expr);
 
        expr = coerce_to_target_type(pstate, expr, type_id,
                                     atttypid, atttypmod,
                                     COERCION_ASSIGNMENT,
                                     COERCE_IMPLICIT_CAST,
                                     -1);
        if (expr == NULL)
            ereport(ERROR,
                    (errcode(ERRCODE_DATATYPE_MISMATCH),
                     errmsg("column \"%s\" is of type %s"
                            " but default expression is of type %s",
                            attname,
                            format_type_be(atttypid),
                            format_type_be(type_id)),
                     errhint("You will need to rewrite or cast the expression.")));
    }
 
    /*
     * Finally, take care of collations in the finished expression.
     */
    assign_expr_collations(pstate, expr);
 
    return expr;
}
 
/*
 * Take a raw CHECK constraint expression and convert it to a cooked format
 * ready for storage.
 *
 * Parse state must be set up to recognize any vars that might appear
 * in the expression.
 */
static Node *
cookConstraint(ParseState *pstate,
               Node *raw_constraint,
               char *relname)
{
    Node       *expr;
 
    /*
     * Transform raw parsetree to executable expression.
     */
    expr = transformExpr(pstate, raw_constraint, EXPR_KIND_CHECK_CONSTRAINT);
 
    /*
     * Make sure it yields a boolean result.
     */
    expr = coerce_to_boolean(pstate, expr, "CHECK");
 
    /*
     * Take care of collations.
     */
    assign_expr_collations(pstate, expr);
 
    /*
     * Make sure no outside relations are referred to (this is probably dead
     * code now that add_missing_from is history).
     */
    if (list_length(pstate->p_rtable) != 1)
        ereport(ERROR,
                (errcode(ERRCODE_INVALID_COLUMN_REFERENCE),
                 errmsg("only table \"%s\" can be referenced in check constraint",
                        relname)));
 
    return expr;
}
 
/*
 * CopyStatistics --- copy entries in pg_statistic from one rel to another
 */
void
CopyStatistics(Oid fromrelid, Oid torelid)
{
    HeapTuple   tup;
    SysScanDesc scan;
    ScanKeyData key[1];
    Relation    statrel;
    CatalogIndexState indstate = NULL;
 
    statrel = table_open(StatisticRelationId, RowExclusiveLock);
 
    /* Now search for stat records */
    ScanKeyInit(&key[0],
                Anum_pg_statistic_starelid,
                BTEqualStrategyNumber, F_OIDEQ,
                ObjectIdGetDatum(fromrelid));
 
    scan = systable_beginscan(statrel, StatisticRelidAttnumInhIndexId,
                              true, NULL, 1, key);
 
    while (HeapTupleIsValid((tup = systable_getnext(scan))))
    {
        Form_pg_statistic statform;
 
        /* make a modifiable copy */
        tup = heap_copytuple(tup);
        statform = (Form_pg_statistic) GETSTRUCT(tup);
 
        /* update the copy of the tuple and insert it */
        statform->starelid = torelid;
 
        /* fetch index information when we know we need it */
        if (indstate == NULL)
            indstate = CatalogOpenIndexes(statrel);
 
        CatalogTupleInsertWithInfo(statrel, tup, indstate);
 
        heap_freetuple(tup);
    }
 
    systable_endscan(scan);
 
    if (indstate != NULL)
        CatalogCloseIndexes(indstate);
    table_close(statrel, RowExclusiveLock);
}
 
/*
 * RemoveStatistics --- remove entries in pg_statistic for a rel or column
 *
 * If attnum is zero, remove all entries for rel; else remove only the one(s)
 * for that column.
 */
void
RemoveStatistics(Oid relid, AttrNumber attnum)
{
    Relation    pgstatistic;
    SysScanDesc scan;
    ScanKeyData key[2];
    int         nkeys;
    HeapTuple   tuple;
 
    pgstatistic = table_open(StatisticRelationId, RowExclusiveLock);
 
    ScanKeyInit(&key[0],
                Anum_pg_statistic_starelid,
                BTEqualStrategyNumber, F_OIDEQ,
                ObjectIdGetDatum(relid));
 
    if (attnum == 0)
        nkeys = 1;
    else
    {
        ScanKeyInit(&key[1],
                    Anum_pg_statistic_staattnum,
                    BTEqualStrategyNumber, F_INT2EQ,
                    Int16GetDatum(attnum));
        nkeys = 2;
    }
 
    scan = systable_beginscan(pgstatistic, StatisticRelidAttnumInhIndexId, true,
                              NULL, nkeys, key);
 
    /* we must loop even when attnum != 0, in case of inherited stats */
    while (HeapTupleIsValid(tuple = systable_getnext(scan)))
        CatalogTupleDelete(pgstatistic, &tuple->t_self);
 
    systable_endscan(scan);
 
    table_close(pgstatistic, RowExclusiveLock);
}
 
 
/*
 * RelationTruncateIndexes - truncate all indexes associated
 * with the heap relation to zero tuples.
 *
 * The routine will truncate and then reconstruct the indexes on
 * the specified relation.  Caller must hold exclusive lock on rel.
 */
static void
RelationTruncateIndexes(Relation heapRelation)
{
    ListCell   *indlist;
 
    /* Ask the relcache to produce a list of the indexes of the rel */
    foreach(indlist, RelationGetIndexList(heapRelation))
    {
        Oid         indexId = lfirst_oid(indlist);
        Relation    currentIndex;
        IndexInfo  *indexInfo;
 
        /* Open the index relation; use exclusive lock, just to be sure */
        currentIndex = index_open(indexId, AccessExclusiveLock);
 
        /*
         * Fetch info needed for index_build.  Since we know there are no
         * tuples that actually need indexing, we can use a dummy IndexInfo.
         * This is slightly cheaper to build, but the real point is to avoid
         * possibly running user-defined code in index expressions or
         * predicates.  We might be getting invoked during ON COMMIT
         * processing, and we don't want to run any such code then.
         */
        indexInfo = BuildDummyIndexInfo(currentIndex);
 
        /*
         * Now truncate the actual file (and discard buffers).
         */
        RelationTruncate(currentIndex, 0);
 
        /* Initialize the index and rebuild */
        /* Note: we do not need to re-establish pkey setting */
        index_build(heapRelation, currentIndex, indexInfo, true, false,
                    true);
 
        /* We're done with this index */
        index_close(currentIndex, NoLock);
    }
}
 
/*
 *   heap_truncate
 *
 *   This routine deletes all data within all the specified relations.
 *
 * This is not transaction-safe!  There is another, transaction-safe
 * implementation in commands/tablecmds.c.  We now use this only for
 * ON COMMIT truncation of temporary tables, where it doesn't matter.
 */
void
heap_truncate(List *relids)
{
    List       *relations = NIL;
    ListCell   *cell;
 
    /* Open relations for processing, and grab exclusive access on each */
    foreach(cell, relids)
    {
        Oid         rid = lfirst_oid(cell);
        Relation    rel;
 
        rel = table_open(rid, AccessExclusiveLock);
        relations = lappend(relations, rel);
    }
 
    /* Don't allow truncate on tables that are referenced by foreign keys */
    heap_truncate_check_FKs(relations, true);
 
    /* OK to do it */
    foreach(cell, relations)
    {
        Relation    rel = lfirst(cell);
 
        /* Truncate the relation */
        heap_truncate_one_rel(rel);
 
        /* Close the relation, but keep exclusive lock on it until commit */
        table_close(rel, NoLock);
    }
}
 
/*
 *   heap_truncate_one_rel
 *
 *   This routine deletes all data within the specified relation.
 *
 * This is not transaction-safe, because the truncation is done immediately
 * and cannot be rolled back later.  Caller is responsible for having
 * checked permissions etc, and must have obtained AccessExclusiveLock.
 */
void
heap_truncate_one_rel(Relation rel)
{
    Oid         toastrelid;
 
    /*
     * Truncate the relation.  Partitioned tables have no storage, so there is
     * nothing to do for them here.
     */
    if (rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
        return;
 
    /* Truncate the underlying relation */
    table_relation_nontransactional_truncate(rel);
 
    /* If the relation has indexes, truncate the indexes too */
    RelationTruncateIndexes(rel);
 
    /* If there is a toast table, truncate that too */
    toastrelid = rel->rd_rel->reltoastrelid;
    if (OidIsValid(toastrelid))
    {
        Relation    toastrel = table_open(toastrelid, AccessExclusiveLock);
 
        table_relation_nontransactional_truncate(toastrel);
        RelationTruncateIndexes(toastrel);
        /* keep the lock... */
        table_close(toastrel, NoLock);
    }
}
 
/*
 * heap_truncate_check_FKs
 *      Check for foreign keys referencing a list of relations that
 *      are to be truncated, and raise error if there are any
 *
 * We disallow such FKs (except self-referential ones) since the whole point
 * of TRUNCATE is to not scan the individual rows to be thrown away.
 *
 * This is split out so it can be shared by both implementations of truncate.
 * Caller should already hold a suitable lock on the relations.
 *
 * tempTables is only used to select an appropriate error message.
 */
void
heap_truncate_check_FKs(List *relations, bool tempTables)
{
    List       *oids = NIL;
    List       *dependents;
    ListCell   *cell;
 
    /*
     * Build a list of OIDs of the interesting relations.
     *
     * If a relation has no triggers, then it can neither have FKs nor be
     * referenced by a FK from another table, so we can ignore it.  For
     * partitioned tables, FKs have no triggers, so we must include them
     * anyway.
     */
    foreach(cell, relations)
    {
        Relation    rel = lfirst(cell);
 
        if (rel->rd_rel->relhastriggers ||
            rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
            oids = lappend_oid(oids, RelationGetRelid(rel));
    }
 
    /*
     * Fast path: if no relation has triggers, none has FKs either.
     */
    if (oids == NIL)
        return;
 
    /*
     * Otherwise, must scan pg_constraint.  We make one pass with all the
     * relations considered; if this finds nothing, then all is well.
     */
    dependents = heap_truncate_find_FKs(oids);
    if (dependents == NIL)
        return;
 
    /*
     * Otherwise we repeat the scan once per relation to identify a particular
     * pair of relations to complain about.  This is pretty slow, but
     * performance shouldn't matter much in a failure path.  The reason for
     * doing things this way is to ensure that the message produced is not
     * dependent on chance row locations within pg_constraint.
     */
    foreach(cell, oids)
    {
        Oid         relid = lfirst_oid(cell);
        ListCell   *cell2;
 
        dependents = heap_truncate_find_FKs(list_make1_oid(relid));
 
        foreach(cell2, dependents)
        {
            Oid         relid2 = lfirst_oid(cell2);
 
            if (!list_member_oid(oids, relid2))
            {
                char       *relname = get_rel_name(relid);
                char       *relname2 = get_rel_name(relid2);
 
                if (tempTables)
                    ereport(ERROR,
                            (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
                             errmsg("unsupported ON COMMIT and foreign key combination"),
                             errdetail("Table \"%s\" references \"%s\", but they do not have the same ON COMMIT setting.",
                                       relname2, relname)));
                else
                    ereport(ERROR,
                            (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
                             errmsg("cannot truncate a table referenced in a foreign key constraint"),
                             errdetail("Table \"%s\" references \"%s\".",
                                       relname2, relname),
                             errhint("Truncate table \"%s\" at the same time, "
                                     "or use TRUNCATE ... CASCADE.",
                                     relname2)));
            }
        }
    }
}
 
/*
 * heap_truncate_find_FKs
 *      Find relations having foreign keys referencing any of the given rels
 *
 * Input and result are both lists of relation OIDs.  The result contains
 * no duplicates, does *not* include any rels that were already in the input
 * list, and is sorted in OID order.  (The last property is enforced mainly
 * to guarantee consistent behavior in the regression tests; we don't want
 * behavior to change depending on chance locations of rows in pg_constraint.)
 *
 * Note: caller should already have appropriate lock on all rels mentioned
 * in relationIds.  Since adding or dropping an FK requires exclusive lock
 * on both rels, this ensures that the answer will be stable.
 */
List *
heap_truncate_find_FKs(List *relationIds)
{
    List       *result = NIL;
    List       *oids;
    List       *parent_cons;
    ListCell   *cell;
    ScanKeyData key;
    Relation    fkeyRel;
    SysScanDesc fkeyScan;
    HeapTuple   tuple;
    bool        restart;
 
    oids = list_copy(relationIds);
 
    /*
     * Must scan pg_constraint.  Right now, it is a seqscan because there is
     * no available index on confrelid.
     */
    fkeyRel = table_open(ConstraintRelationId, AccessShareLock);
 
restart:
    restart = false;
    parent_cons = NIL;
 
    fkeyScan = systable_beginscan(fkeyRel, InvalidOid, false,
                                  NULL, 0, NULL);
 
    while (HeapTupleIsValid(tuple = systable_getnext(fkeyScan)))
    {
        Form_pg_constraint con = (Form_pg_constraint) GETSTRUCT(tuple);
 
        /* Not a foreign key */
        if (con->contype != CONSTRAINT_FOREIGN)
            continue;
 
        /* Not referencing one of our list of tables */
        if (!list_member_oid(oids, con->confrelid))
            continue;
 
        /*
         * If this constraint has a parent constraint which we have not seen
         * yet, keep track of it for the second loop, below.  Tracking parent
         * constraints allows us to climb up to the top-level constraint and
         * look for all possible relations referencing the partitioned table.
         */
        if (OidIsValid(con->conparentid) &&
            !list_member_oid(parent_cons, con->conparentid))
            parent_cons = lappend_oid(parent_cons, con->conparentid);
 
        /*
         * Add referencer to result, unless present in input list.  (Don't
         * worry about dupes: we'll fix that below).
         */
        if (!list_member_oid(relationIds, con->conrelid))
            result = lappend_oid(result, con->conrelid);
    }
 
    systable_endscan(fkeyScan);
 
    /*
     * Process each parent constraint we found to add the list of referenced
     * relations by them to the oids list.  If we do add any new such
     * relations, redo the first loop above.  Also, if we see that the parent
     * constraint in turn has a parent, add that so that we process all
     * relations in a single additional pass.
     */
    foreach(cell, parent_cons)
    {
        Oid         parent = lfirst_oid(cell);
 
        ScanKeyInit(&key,
                    Anum_pg_constraint_oid,
                    BTEqualStrategyNumber, F_OIDEQ,
                    ObjectIdGetDatum(parent));
 
        fkeyScan = systable_beginscan(fkeyRel, ConstraintOidIndexId,
                                      true, NULL, 1, &key);
 
        tuple = systable_getnext(fkeyScan);
        if (HeapTupleIsValid(tuple))
        {
            Form_pg_constraint con = (Form_pg_constraint) GETSTRUCT(tuple);
 
            /*
             * pg_constraint rows always appear for partitioned hierarchies
             * this way: on the each side of the constraint, one row appears
             * for each partition that points to the top-most table on the
             * other side.
             *
             * Because of this arrangement, we can correctly catch all
             * relevant relations by adding to 'parent_cons' all rows with
             * valid conparentid, and to the 'oids' list all rows with a zero
             * conparentid.  If any oids are added to 'oids', redo the first
             * loop above by setting 'restart'.
             */
            if (OidIsValid(con->conparentid))
                parent_cons = list_append_unique_oid(parent_cons,
                                                     con->conparentid);
            else if (!list_member_oid(oids, con->confrelid))
            {
                oids = lappend_oid(oids, con->confrelid);
                restart = true;
            }
        }
 
        systable_endscan(fkeyScan);
    }
 
    list_free(parent_cons);
    if (restart)
        goto restart;
 
    table_close(fkeyRel, AccessShareLock);
    list_free(oids);
 
    /* Now sort and de-duplicate the result list */
    list_sort(result, list_oid_cmp);
    list_deduplicate_oid(result);
 
    return result;
}
 
/*
 * StorePartitionKey
 *      Store information about the partition key rel into the catalog
 */
void
StorePartitionKey(Relation rel,
                  char strategy,
                  int16 partnatts,
                  AttrNumber *partattrs,
                  List *partexprs,
                  Oid *partopclass,
                  Oid *partcollation)
{
    int         i;
    int2vector *partattrs_vec;
    oidvector  *partopclass_vec;
    oidvector  *partcollation_vec;
    Datum       partexprDatum;
    Relation    pg_partitioned_table;
    HeapTuple   tuple;
    Datum       values[Natts_pg_partitioned_table];
    bool        nulls[Natts_pg_partitioned_table] = {0};
    ObjectAddress myself;
    ObjectAddress referenced;
    ObjectAddresses *addrs;
 
    Assert(rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE);
 
    /* Copy the partition attribute numbers, opclass OIDs into arrays */
    partattrs_vec = buildint2vector(partattrs, partnatts);
    partopclass_vec = buildoidvector(partopclass, partnatts);
    partcollation_vec = buildoidvector(partcollation, partnatts);
 
    /* Convert the expressions (if any) to a text datum */
    if (partexprs)
    {
        char       *exprString;
 
        exprString = nodeToString(partexprs);
        partexprDatum = CStringGetTextDatum(exprString);
        pfree(exprString);
    }
    else
        partexprDatum = (Datum) 0;
 
    pg_partitioned_table = table_open(PartitionedRelationId, RowExclusiveLock);
 
    /* Only this can ever be NULL */
    if (!partexprDatum)
        nulls[Anum_pg_partitioned_table_partexprs - 1] = true;
 
    values[Anum_pg_partitioned_table_partrelid - 1] = ObjectIdGetDatum(RelationGetRelid(rel));
    values[Anum_pg_partitioned_table_partstrat - 1] = CharGetDatum(strategy);
    values[Anum_pg_partitioned_table_partnatts - 1] = Int16GetDatum(partnatts);
    values[Anum_pg_partitioned_table_partdefid - 1] = ObjectIdGetDatum(InvalidOid);
    values[Anum_pg_partitioned_table_partattrs - 1] = PointerGetDatum(partattrs_vec);
    values[Anum_pg_partitioned_table_partclass - 1] = PointerGetDatum(partopclass_vec);
    values[Anum_pg_partitioned_table_partcollation - 1] = PointerGetDatum(partcollation_vec);
    values[Anum_pg_partitioned_table_partexprs - 1] = partexprDatum;
 
    tuple = heap_form_tuple(RelationGetDescr(pg_partitioned_table), values, nulls);
 
    CatalogTupleInsert(pg_partitioned_table, tuple);
    table_close(pg_partitioned_table, RowExclusiveLock);
 
    /* Mark this relation as dependent on a few things as follows */
    addrs = new_object_addresses();
    ObjectAddressSet(myself, RelationRelationId, RelationGetRelid(rel));
 
    /* Operator class and collation per key column */
    for (i = 0; i < partnatts; i++)
    {
        ObjectAddressSet(referenced, OperatorClassRelationId, partopclass[i]);
        add_exact_object_address(&referenced, addrs);
 
        /* The default collation is pinned, so don't bother recording it */
        if (OidIsValid(partcollation[i]) &&
            partcollation[i] != DEFAULT_COLLATION_OID)
        {
            ObjectAddressSet(referenced, CollationRelationId, partcollation[i]);
            add_exact_object_address(&referenced, addrs);
        }
    }
 
    record_object_address_dependencies(&myself, addrs, DEPENDENCY_NORMAL);
    free_object_addresses(addrs);
 
    /*
     * The partitioning columns are made internally dependent on the table,
     * because we cannot drop any of them without dropping the whole table.
     * (ATExecDropColumn independently enforces that, but it's not bulletproof
     * so we need the dependencies too.)
     */
    for (i = 0; i < partnatts; i++)
    {
        if (partattrs[i] == 0)
            continue;           /* ignore expressions here */
 
        ObjectAddressSubSet(referenced, RelationRelationId,
                            RelationGetRelid(rel), partattrs[i]);
        recordDependencyOn(&referenced, &myself, DEPENDENCY_INTERNAL);
    }
 
    /*
     * Also consider anything mentioned in partition expressions.  External
     * references (e.g. functions) get NORMAL dependencies.  Table columns
     * mentioned in the expressions are handled the same as plain partitioning
     * columns, i.e. they become internally dependent on the whole table.
     */
    if (partexprs)
        recordDependencyOnSingleRelExpr(&myself,
                                        (Node *) partexprs,
                                        RelationGetRelid(rel),
                                        DEPENDENCY_NORMAL,
                                        DEPENDENCY_INTERNAL,
                                        true /* reverse the self-deps */ );
 
    /*
     * We must invalidate the relcache so that the next
     * CommandCounterIncrement() will cause the same to be rebuilt using the
     * information in just created catalog entry.
     */
    CacheInvalidateRelcache(rel);
}
 
/*
 *  RemovePartitionKeyByRelId
 *      Remove pg_partitioned_table entry for a relation
 */
void
RemovePartitionKeyByRelId(Oid relid)
{
    Relation    rel;
    HeapTuple   tuple;
 
    rel = table_open(PartitionedRelationId, RowExclusiveLock);
 
    tuple = SearchSysCache1(PARTRELID, ObjectIdGetDatum(relid));
    if (!HeapTupleIsValid(tuple))
        elog(ERROR, "cache lookup failed for partition key of relation %u",
             relid);
 
    CatalogTupleDelete(rel, &tuple->t_self);
 
    ReleaseSysCache(tuple);
    table_close(rel, RowExclusiveLock);
}
 
/*
 * StorePartitionBound
 *      Update pg_class tuple of rel to store the partition bound and set
 *      relispartition to true
 *
 * If this is the default partition, also update the default partition OID in
 * pg_partitioned_table.
 *
 * Also, invalidate the parent's relcache, so that the next rebuild will load
 * the new partition's info into its partition descriptor.  If there is a
 * default partition, we must invalidate its relcache entry as well.
 */
void
StorePartitionBound(Relation rel, Relation parent, PartitionBoundSpec *bound)
{
    Relation    classRel;
    HeapTuple   tuple,
                newtuple;
    Datum       new_val[Natts_pg_class];
    bool        new_null[Natts_pg_class],
                new_repl[Natts_pg_class];
    Oid         defaultPartOid;
 
    /* Update pg_class tuple */
    classRel = table_open(RelationRelationId, RowExclusiveLock);
    tuple = SearchSysCacheCopy1(RELOID,
                                ObjectIdGetDatum(RelationGetRelid(rel)));
    if (!HeapTupleIsValid(tuple))
        elog(ERROR, "cache lookup failed for relation %u",
             RelationGetRelid(rel));
 
#ifdef USE_ASSERT_CHECKING
    {
        Form_pg_class classForm;
        bool        isnull;
 
        classForm = (Form_pg_class) GETSTRUCT(tuple);
        Assert(!classForm->relispartition);
        (void) SysCacheGetAttr(RELOID, tuple, Anum_pg_class_relpartbound,
                               &isnull);
        Assert(isnull);
    }
#endif
 
    /* Fill in relpartbound value */
    memset(new_val, 0, sizeof(new_val));
    memset(new_null, false, sizeof(new_null));
    memset(new_repl, false, sizeof(new_repl));
    new_val[Anum_pg_class_relpartbound - 1] = CStringGetTextDatum(nodeToString(bound));
    new_null[Anum_pg_class_relpartbound - 1] = false;
    new_repl[Anum_pg_class_relpartbound - 1] = true;
    newtuple = heap_modify_tuple(tuple, RelationGetDescr(classRel),
                                 new_val, new_null, new_repl);
    /* Also set the flag */
    ((Form_pg_class) GETSTRUCT(newtuple))->relispartition = true;
 
    /*
     * We already checked for no inheritance children, but reset
     * relhassubclass in case it was left over.
     */
    if (rel->rd_rel->relkind == RELKIND_RELATION && rel->rd_rel->relhassubclass)
        ((Form_pg_class) GETSTRUCT(newtuple))->relhassubclass = false;
 
    CatalogTupleUpdate(classRel, &newtuple->t_self, newtuple);
    heap_freetuple(newtuple);
    table_close(classRel, RowExclusiveLock);
 
    /*
     * If we're storing bounds for the default partition, update
     * pg_partitioned_table too.
     */
    if (bound->is_default)
        update_default_partition_oid(RelationGetRelid(parent),
                                     RelationGetRelid(rel));
 
    /* Make these updates visible */
    CommandCounterIncrement();
 
    /*
     * The partition constraint for the default partition depends on the
     * partition bounds of every other partition, so we must invalidate the
     * relcache entry for that partition every time a partition is added or
     * removed.
     */
    defaultPartOid =
        get_default_oid_from_partdesc(RelationGetPartitionDesc(parent, true));
    if (OidIsValid(defaultPartOid))
        CacheInvalidateRelcacheByRelid(defaultPartOid);
 
    CacheInvalidateRelcache(parent);
}