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Make set_function_size_estimates() marginally smarter: per original

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comment, it can at least test whether the expression returns set.
This commit is contained in:
Tom Lane 2005-10-05 17:19:19 +00:00
parent 93d358a8a4
commit e011459029
1 changed files with 10 additions and 4 deletions
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14
src/backend/optimizer/path/costsize.c
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@ -49,7 +49,7 @@
* Portions Copyright (c) 1994, Regents of the University of California * Portions Copyright (c) 1994, Regents of the University of California
* *
* IDENTIFICATION * IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/optimizer/path/costsize.c,v 1.147 2005/08/27 22:37:00 tgl Exp $ * $PostgreSQL: pgsql/src/backend/optimizer/path/costsize.c,v 1.148 2005/10/05 17:19:19 tgl Exp $
* *
*------------------------------------------------------------------------- *-------------------------------------------------------------------------
*/ */
@ -1898,17 +1898,23 @@ join_in_selectivity(JoinPath *path, PlannerInfo *root)
void void
set_function_size_estimates(PlannerInfo *root, RelOptInfo *rel) set_function_size_estimates(PlannerInfo *root, RelOptInfo *rel)
{ {
RangeTblEntry *rte;
/* Should only be applied to base relations that are functions */ /* Should only be applied to base relations that are functions */
Assert(rel->relid > 0); Assert(rel->relid > 0);
Assert(rel->rtekind == RTE_FUNCTION); rte = rt_fetch(rel->relid, root->parse->rtable);
Assert(rte->rtekind == RTE_FUNCTION);
/* /*
* Estimate number of rows the function itself will return. * Estimate number of rows the function itself will return.
* *
* XXX no idea how to do this yet; but should at least check whether * XXX no idea how to do this yet; but we can at least check whether
* function returns set or not... * function returns set or not...
*/ */
rel->tuples = 1000; if (expression_returns_set(rte->funcexpr))
rel->tuples = 1000;
else
rel->tuples = 1;
/* Now estimate number of output rows, etc */ /* Now estimate number of output rows, etc */
set_baserel_size_estimates(root, rel); set_baserel_size_estimates(root, rel);