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Merge restrictlist_selectivity into clauselist_selectivity by

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teaching the latter to accept either RestrictInfo nodes or bare
clause expressions; and cache the selectivity result in the RestrictInfo
node when possible.  This extends the caching behavior of approx_selectivity
to many more contexts, and should reduce duplicate selectivity
calculations.
This commit is contained in:
Tom Lane
2004-01-04 03:51:52 +00:00
parent 21a1202281
commit 82b4dd394f
12 changed files with 196 additions and 200 deletions
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24
src/backend/optimizer/util/restrictinfo.c
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@@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/optimizer/util/restrictinfo.c,v 1.22 2004/01/04 00:07:32 tgl Exp $
* $PostgreSQL: pgsql/src/backend/optimizer/util/restrictinfo.c,v 1.23 2004/01/04 03:51:52 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -47,12 +47,16 @@ make_restrictinfo(Expr *clause, bool ispusheddown)
/*
* If it's a binary opclause, set up left/right relids info.
* In any case set up the total clause relids info.
*/
if (is_opclause(clause) && length(((OpExpr *) clause)->args) == 2)
{
restrictinfo->left_relids = pull_varnos(get_leftop(clause));
restrictinfo->right_relids = pull_varnos(get_rightop(clause));
restrictinfo->clause_relids = bms_union(restrictinfo->left_relids,
restrictinfo->right_relids);
/*
* Does it look like a normal join clause, i.e., a binary operator
* relating expressions that come from distinct relations? If so
@@ -67,9 +71,11 @@ make_restrictinfo(Expr *clause, bool ispusheddown)
}
else
{
/* Not a binary opclause, so mark both relid sets as empty */
/* Not a binary opclause, so mark left/right relid sets as empty */
restrictinfo->left_relids = NULL;
restrictinfo->right_relids = NULL;
/* and get the total relid set the hard way */
restrictinfo->clause_relids = pull_varnos((Node *) clause);
}
/*
@@ -328,9 +334,13 @@ join_clause_is_redundant(Query *root,
bool redundant = false;
List *refitem;
/* do the cheap test first: is it a "var = const" clause? */
if (bms_is_empty(rinfo->left_relids) ||
bms_is_empty(rinfo->right_relids))
return false; /* var = const, so not redundant */
cache_mergeclause_pathkeys(root, rinfo);
/* do the cheap tests first */
foreach(refitem, reference_list)
{
RestrictInfo *refrinfo = (RestrictInfo *) lfirst(refitem);
@@ -347,13 +357,7 @@ join_clause_is_redundant(Query *root,
}
if (redundant)
{
/* It looks redundant, but check for "var = const" case */
if (!bms_is_empty(rinfo->left_relids) &&
!bms_is_empty(rinfo->right_relids))
return true; /* var = var, so redundant */
/* else var = const, not redundant */
}
return true; /* var = var, so redundant */
}
/* otherwise, not redundant */