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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

14
src/backend/optimizer/path/costsize.c

@ -49,7 +49,7 @@
* Portions Copyright (c) 1994, Regents of the University of California
*
* 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
set_function_size_estimates(PlannerInfo *root, RelOptInfo *rel)
{
RangeTblEntry *rte;
/* Should only be applied to base relations that are functions */
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.
*
* 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...
*/
rel->tuples = 1000;
if (expression_returns_set(rte->funcexpr))
rel->tuples = 1000;
else
rel->tuples = 1;
/* Now estimate number of output rows, etc */
set_baserel_size_estimates(root, rel);