preptlist.c File Reference

#include "postgres.h"
#include "access/table.h"
#include "nodes/makefuncs.h"
#include "optimizer/appendinfo.h"
#include "optimizer/optimizer.h"
#include "optimizer/prep.h"
#include "optimizer/tlist.h"
#include "parser/parse_coerce.h"
#include "parser/parsetree.h"
#include "utils/rel.h"

Include dependency graph for preptlist.c:

Go to the source code of this file.

Functions
static List *	expand_insert_targetlist (List *tlist, Relation rel)
void	preprocess_targetlist (PlannerInfo *root)
List *	extract_update_targetlist_colnos (List *tlist)
PlanRowMark *	get_plan_rowmark (List *rowmarks, Index rtindex)

Function Documentation

expand_insert_targetlist()

static List * expand_insert_targetlist ( List *  tlist, Relation  rel  )

static

Definition at line 295 of file preptlist.c.

References COERCE_IMPLICIT_CAST, coerce_to_domain(), COERCION_IMPLICIT, elog, ERROR, flatCopyTargetEntry(), InvalidOid, lappend(), lfirst, list_head(), lnext(), makeConst(), makeTargetEntry(), NameStr, NIL, pstrdup(), RelationData::rd_att, RelationGetNumberOfAttributes, TargetEntry::resjunk, TargetEntry::resno, and TupleDescAttr.

Referenced by preprocess_targetlist().

{
    List       *new_tlist = NIL;
    ListCell   *tlist_item;
    int         attrno,
                numattrs;

    tlist_item = list_head(tlist);

    /*
     * The rewriter should have already ensured that the TLEs are in correct
     * order; but we have to insert TLEs for any missing attributes.
     *
     * Scan the tuple description in the relation's relcache entry to make
     * sure we have all the user attributes in the right order.
     */
    numattrs = RelationGetNumberOfAttributes(rel);

    for (attrno = 1; attrno <= numattrs; attrno++)
    {
        Form_pg_attribute att_tup = TupleDescAttr(rel->rd_att, attrno - 1);
        TargetEntry *new_tle = NULL;

        if (tlist_item != NULL)
        {
            TargetEntry *old_tle = (TargetEntry *) lfirst(tlist_item);

            if (!old_tle->resjunk && old_tle->resno == attrno)
            {
                new_tle = old_tle;
                tlist_item = lnext(tlist, tlist_item);
            }
        }

        if (new_tle == NULL)
        {
            /*
             * Didn't find a matching tlist entry, so make one.
             *
             * INSERTs should insert NULL in this case.  (We assume the
             * rewriter would have inserted any available non-NULL default
             * value.)  Also, if the column isn't dropped, apply any domain
             * constraints that might exist --- this is to catch domain NOT
             * NULL.
             *
             * When generating a NULL constant for a dropped column, we label
             * it INT4 (any other guaranteed-to-exist datatype would do as
             * well). We can't label it with the dropped column's datatype
             * since that might not exist anymore.  It does not really matter
             * what we claim the type is, since NULL is NULL --- its
             * representation is datatype-independent.  This could perhaps
             * confuse code comparing the finished plan to the target
             * relation, however.
             */
            Oid         atttype = att_tup->atttypid;
            Oid         attcollation = att_tup->attcollation;
            Node       *new_expr;

            if (!att_tup->attisdropped)
            {
                new_expr = (Node *) makeConst(atttype,
                                              -1,
                                              attcollation,
                                              att_tup->attlen,
                                              (Datum) 0,
                                              true, /* isnull */
                                              att_tup->attbyval);
                new_expr = coerce_to_domain(new_expr,
                                            InvalidOid, -1,
                                            atttype,
                                            COERCION_IMPLICIT,
                                            COERCE_IMPLICIT_CAST,
                                            -1,
                                            false);
            }
            else
            {
                /* Insert NULL for dropped column */
                new_expr = (Node *) makeConst(INT4OID,
                                              -1,
                                              InvalidOid,
                                              sizeof(int32),
                                              (Datum) 0,
                                              true, /* isnull */
                                              true /* byval */ );
            }

            new_tle = makeTargetEntry((Expr *) new_expr,
                                      attrno,
                                      pstrdup(NameStr(att_tup->attname)),
                                      false);
        }

        new_tlist = lappend(new_tlist, new_tle);
    }

    /*
     * The remaining tlist entries should be resjunk; append them all to the
     * end of the new tlist, making sure they have resnos higher than the last
     * real attribute.  (Note: although the rewriter already did such
     * renumbering, we have to do it again here in case we added NULL entries
     * above.)
     */
    while (tlist_item)
    {
        TargetEntry *old_tle = (TargetEntry *) lfirst(tlist_item);

        if (!old_tle->resjunk)
            elog(ERROR, "targetlist is not sorted correctly");
        /* Get the resno right, but don't copy unnecessarily */
        if (old_tle->resno != attrno)
        {
            old_tle = flatCopyTargetEntry(old_tle);
            old_tle->resno = attrno;
        }
        new_tlist = lappend(new_tlist, old_tle);
        attrno++;
        tlist_item = lnext(tlist, tlist_item);
    }

    return new_tlist;
}

extract_update_targetlist_colnos()

List* extract_update_targetlist_colnos

(

List *

tlist

)

Definition at line 261 of file preptlist.c.

References lappend_int(), lfirst, NIL, TargetEntry::resjunk, and TargetEntry::resno.

Referenced by make_modifytable(), and preprocess_targetlist().

{
    List       *update_colnos = NIL;
    AttrNumber  nextresno = 1;
    ListCell   *lc;

    foreach(lc, tlist)
    {
        TargetEntry *tle = (TargetEntry *) lfirst(lc);

        if (!tle->resjunk)
            update_colnos = lappend_int(update_colnos, tle->resno);
        tle->resno = nextresno++;
    }
    return update_colnos;
}

get_plan_rowmark()

PlanRowMark* get_plan_rowmark	(	List *	rowmarks,
		Index	rtindex
	)

Definition at line 425 of file preptlist.c.

References lfirst, and PlanRowMark::rti.

Referenced by check_index_predicates(), deparseLockingClause(), and expand_inherited_rtentry().

{
    ListCell   *l;

    foreach(l, rowmarks)
    {
        PlanRowMark *rc = (PlanRowMark *) lfirst(l);

        if (rc->rti == rtindex)
            return rc;
    }
    return NULL;
}

preprocess_targetlist()

void preprocess_targetlist

(

PlannerInfo *

root

)

Definition at line 62 of file preptlist.c.

References add_row_identity_columns(), PlanRowMark::allMarkTypes, Assert, CMD_DELETE, CMD_INSERT, CMD_SELECT, CMD_UPDATE, Query::commandType, elog, ERROR, expand_insert_targetlist(), extract_update_targetlist_colnos(), RangeTblEntry::inh, InvalidOid, IsA, PlanRowMark::isParent, lappend(), lfirst, list_free(), list_length(), makeTargetEntry(), makeVar(), makeWholeRowVar(), NoLock, parse(), PlannerInfo::parse, PlannerInfo::processed_tlist, PlanRowMark::prti, pstrdup(), pull_var_clause(), PVC_INCLUDE_PLACEHOLDERS, PVC_RECURSE_AGGREGATES, PVC_RECURSE_WINDOWFUNCS, RangeTblEntry::relid, Query::resultRelation, Query::returningList, ROW_MARK_COPY, PlanRowMark::rowmarkId, PlannerInfo::rowMarks, rt_fetch, Query::rtable, RTE_RELATION, RangeTblEntry::rtekind, PlanRowMark::rti, SelfItemPointerAttributeNumber, snprintf, table_close(), table_open(), TableOidAttributeNumber, Query::targetList, tlist_member(), PlannerInfo::update_colnos, and Var::varno.

Referenced by grouping_planner().

{
    Query      *parse = root->parse;
    int         result_relation = parse->resultRelation;
    List       *range_table = parse->rtable;
    CmdType     command_type = parse->commandType;
    RangeTblEntry *target_rte = NULL;
    Relation    target_relation = NULL;
    List       *tlist;
    ListCell   *lc;

    /*
     * If there is a result relation, open it so we can look for missing
     * columns and so on.  We assume that previous code already acquired at
     * least AccessShareLock on the relation, so we need no lock here.
     */
    if (result_relation)
    {
        target_rte = rt_fetch(result_relation, range_table);

        /*
         * Sanity check: it'd better be a real relation not, say, a subquery.
         * Else parser or rewriter messed up.
         */
        if (target_rte->rtekind != RTE_RELATION)
            elog(ERROR, "result relation must be a regular relation");

        target_relation = table_open(target_rte->relid, NoLock);
    }
    else
        Assert(command_type == CMD_SELECT);

    /*
     * In an INSERT, the executor expects the targetlist to match the exact
     * order of the target table's attributes, including entries for
     * attributes not mentioned in the source query.
     *
     * In an UPDATE, we don't rearrange the tlist order, but we need to make a
     * separate list of the target attribute numbers, in tlist order, and then
     * renumber the processed_tlist entries to be consecutive.
     */
    tlist = parse->targetList;
    if (command_type == CMD_INSERT)
        tlist = expand_insert_targetlist(tlist, target_relation);
    else if (command_type == CMD_UPDATE)
        root->update_colnos = extract_update_targetlist_colnos(tlist);

    /*
     * For non-inherited UPDATE/DELETE, register any junk column(s) needed to
     * allow the executor to identify the rows to be updated or deleted.  In
     * the inheritance case, we do nothing now, leaving this to be dealt with
     * when expand_inherited_rtentry() makes the leaf target relations.  (But
     * there might not be any leaf target relations, in which case we must do
     * this in distribute_row_identity_vars().)
     */
    if ((command_type == CMD_UPDATE || command_type == CMD_DELETE) &&
        !target_rte->inh)
    {
        /* row-identity logic expects to add stuff to processed_tlist */
        root->processed_tlist = tlist;
        add_row_identity_columns(root, result_relation,
                                 target_rte, target_relation);
        tlist = root->processed_tlist;
    }

    /*
     * Add necessary junk columns for rowmarked rels.  These values are needed
     * for locking of rels selected FOR UPDATE/SHARE, and to do EvalPlanQual
     * rechecking.  See comments for PlanRowMark in plannodes.h.  If you
     * change this stanza, see also expand_inherited_rtentry(), which has to
     * be able to add on junk columns equivalent to these.
     *
     * (Someday it might be useful to fold these resjunk columns into the
     * row-identity-column management used for UPDATE/DELETE.  Today is not
     * that day, however.  One notable issue is that it seems important that
     * the whole-row Vars made here use the real table rowtype, not RECORD, so
     * that conversion to/from child relations' rowtypes will happen.  Also,
     * since these entries don't potentially bloat with more and more child
     * relations, there's not really much need for column sharing.)
     */
    foreach(lc, root->rowMarks)
    {
        PlanRowMark *rc = (PlanRowMark *) lfirst(lc);
        Var        *var;
        char        resname[32];
        TargetEntry *tle;

        /* child rels use the same junk attrs as their parents */
        if (rc->rti != rc->prti)
            continue;

        if (rc->allMarkTypes & ~(1 << ROW_MARK_COPY))
        {
            /* Need to fetch TID */
            var = makeVar(rc->rti,
                          SelfItemPointerAttributeNumber,
                          TIDOID,
                          -1,
                          InvalidOid,
                          0);
            snprintf(resname, sizeof(resname), "ctid%u", rc->rowmarkId);
            tle = makeTargetEntry((Expr *) var,
                                  list_length(tlist) + 1,
                                  pstrdup(resname),
                                  true);
            tlist = lappend(tlist, tle);
        }
        if (rc->allMarkTypes & (1 << ROW_MARK_COPY))
        {
            /* Need the whole row as a junk var */
            var = makeWholeRowVar(rt_fetch(rc->rti, range_table),
                                  rc->rti,
                                  0,
                                  false);
            snprintf(resname, sizeof(resname), "wholerow%u", rc->rowmarkId);
            tle = makeTargetEntry((Expr *) var,
                                  list_length(tlist) + 1,
                                  pstrdup(resname),
                                  true);
            tlist = lappend(tlist, tle);
        }

        /* If parent of inheritance tree, always fetch the tableoid too. */
        if (rc->isParent)
        {
            var = makeVar(rc->rti,
                          TableOidAttributeNumber,
                          OIDOID,
                          -1,
                          InvalidOid,
                          0);
            snprintf(resname, sizeof(resname), "tableoid%u", rc->rowmarkId);
            tle = makeTargetEntry((Expr *) var,
                                  list_length(tlist) + 1,
                                  pstrdup(resname),
                                  true);
            tlist = lappend(tlist, tle);
        }
    }

    /*
     * If the query has a RETURNING list, add resjunk entries for any Vars
     * used in RETURNING that belong to other relations.  We need to do this
     * to make these Vars available for the RETURNING calculation.  Vars that
     * belong to the result rel don't need to be added, because they will be
     * made to refer to the actual heap tuple.
     */
    if (parse->returningList && list_length(parse->rtable) > 1)
    {
        List       *vars;
        ListCell   *l;

        vars = pull_var_clause((Node *) parse->returningList,
                               PVC_RECURSE_AGGREGATES |
                               PVC_RECURSE_WINDOWFUNCS |
                               PVC_INCLUDE_PLACEHOLDERS);
        foreach(l, vars)
        {
            Var        *var = (Var *) lfirst(l);
            TargetEntry *tle;

            if (IsA(var, Var) &&
                var->varno == result_relation)
                continue;       /* don't need it */

            if (tlist_member((Expr *) var, tlist))
                continue;       /* already got it */

            tle = makeTargetEntry((Expr *) var,
                                  list_length(tlist) + 1,
                                  NULL,
                                  true);

            tlist = lappend(tlist, tle);
        }
        list_free(vars);
    }

    root->processed_tlist = tlist;

    if (target_relation)
        table_close(target_relation, NoLock);
}