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Fix nasty bug in optimization of multiway joins: optimizer

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would sometimes generate a plan that omitted a sort step before merge.
This commit is contained in:
Tom Lane
1999-04-03 00:18:28 +00:00
parent 97c52abcc5
commit ff38837fe9
4 changed files with 35 additions and 41 deletions
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20
src/backend/optimizer/path/mergeutils.c
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@@ -7,7 +7,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/optimizer/path/Attic/mergeutils.c,v 1.20 1999/03/01 00:10:32 tgl Exp $
* $Header: /cvsroot/pgsql/src/backend/optimizer/path/Attic/mergeutils.c,v 1.21 1999/04/03 00:18:28 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -36,14 +36,15 @@
* Something to fix next time...
*
* 'restrictinfo_list' is the list of restrictinfo nodes
* 'inner_relid' is the relid of the inner join relation
* 'inner_relids' is the list of relids in the inner join relation
* (used to determine whether a join var is inner or outer)
*
* Returns the new list of mergeinfo nodes.
*
*/
List *
group_clauses_by_order(List *restrictinfo_list,
int inner_relid)
Relids inner_relids)
{
List *mergeinfo_list = NIL;
List *xrestrictinfo;
@@ -59,26 +60,25 @@ group_clauses_by_order(List *restrictinfo_list,
* Create a new mergeinfo node and add it to 'mergeinfo_list'
* if one does not yet exist for this merge ordering.
*/
PathOrder *pathorder;
MergeInfo *xmergeinfo;
Expr *clause = restrictinfo->clause;
Var *leftop = get_leftop(clause);
Var *rightop = get_rightop(clause);
PathOrder *pathorder;
MergeInfo *xmergeinfo;
JoinKey *jmkeys;
pathorder = makeNode(PathOrder);
pathorder->ordtype = MERGE_ORDER;
pathorder->ord.merge = merge_ordering;
xmergeinfo = match_order_mergeinfo(pathorder, mergeinfo_list);
if (inner_relid == leftop->varno)
jmkeys = makeNode(JoinKey);
if (intMember(leftop->varno, inner_relids))
{
jmkeys = makeNode(JoinKey);
jmkeys->outer = rightop;
jmkeys->inner = leftop;
}
else
{
jmkeys = makeNode(JoinKey);
jmkeys->outer = leftop;
jmkeys->inner = rightop;
}
@@ -86,10 +86,8 @@ group_clauses_by_order(List *restrictinfo_list,
if (xmergeinfo == NULL)
{
xmergeinfo = makeNode(MergeInfo);
xmergeinfo->m_ordering = merge_ordering;
mergeinfo_list = lcons(xmergeinfo,
mergeinfo_list);
mergeinfo_list = lcons(xmergeinfo, mergeinfo_list);
}
xmergeinfo->jmethod.clauses = lcons(clause,