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First cut at full support for OUTER JOINs. There are still a few loose

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ends to clean up (see my message of same date to pghackers), but mostly
it works.  INITDB REQUIRED!
This commit is contained in:
Tom Lane
2000-09-12 21:07:18 +00:00
parent b5c0ab278b
commit ed5003c584
93 changed files with 6386 additions and 4262 deletions
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41
src/backend/optimizer/path/pathkeys.c
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@ -11,7 +11,7 @@
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/optimizer/path/pathkeys.c,v 1.24 2000/08/08 15:41:31 tgl Exp $
* $Header: /cvsroot/pgsql/src/backend/optimizer/path/pathkeys.c,v 1.25 2000/09/12 21:06:53 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -694,8 +694,8 @@ find_mergeclauses_for_pathkeys(List *pathkeys, List *restrictinfos)
*
* 'mergeclauses' is a list of RestrictInfos for mergejoin clauses
* that will be used in a merge join.
* 'tlist' is a relation target list for either the inner or outer
* side of the proposed join rel. (Not actually needed anymore)
* 'rel' is the relation the pathkeys will apply to (ie, either the inner
* or outer side of the proposed join rel).
*
* Returns a pathkeys list that can be applied to the indicated relation.
*
@ -706,7 +706,7 @@ find_mergeclauses_for_pathkeys(List *pathkeys, List *restrictinfos)
List *
make_pathkeys_for_mergeclauses(Query *root,
List *mergeclauses,
List *tlist)
RelOptInfo *rel)
{
List *pathkeys = NIL;
List *i;
@ -722,30 +722,37 @@ make_pathkeys_for_mergeclauses(Query *root,
Assert(restrictinfo->mergejoinoperator != InvalidOid);
/*
* Find the key and sortop needed for this mergeclause.
*
* Both sides of the mergeclause should appear in one of the query's
* pathkey equivalence classes, so it doesn't matter which one we
* use here.
* Which key and sortop is needed for this relation?
*/
key = (Node *) get_leftop(restrictinfo->clause);
sortop = restrictinfo->left_sortop;
if (!IsA(key, Var) ||
!intMember(((Var *) key)->varno, rel->relids))
{
key = (Node *) get_rightop(restrictinfo->clause);
sortop = restrictinfo->right_sortop;
if (!IsA(key, Var) ||
!intMember(((Var *) key)->varno, rel->relids))
elog(ERROR, "make_pathkeys_for_mergeclauses: can't identify which side of mergeclause to use");
}
/*
* Find pathkey sublist for this sort item. We expect to find the
* canonical set including the mergeclause's left and right sides;
* if we get back just the one item, something is rotten.
* Find or create canonical pathkey sublist for this sort item.
*/
item = makePathKeyItem(key, sortop);
pathkey = make_canonical_pathkey(root, item);
Assert(length(pathkey) > 1);
/*
* Since the item we just made is not in the returned canonical
* set, we can free it --- this saves a useful amount of storage
* in a big join tree.
* Most of the time we will get back a canonical pathkey set
* including both the mergeclause's left and right sides (the only
* case where we don't is if the mergeclause appeared in an OUTER
* JOIN, which causes us not to generate an equijoin set from it).
* Therefore, most of the time the item we just made is not part
* of the returned structure, and we can free it. This check
* saves a useful amount of storage in a big join tree.
*/
pfree(item);
if (item != (PathKeyItem *) lfirst(pathkey))
pfree(item);
pathkeys = lappend(pathkeys, pathkey);
}