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Teach planner to convert simple UNION ALL subqueries into append relations,

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thereby sharing code with the inheritance case.  This puts the UNION-ALL-view
approach to partitioned tables on par with inheritance, so far as constraint
exclusion is concerned: it works either way.  (Still need to update the docs
to say so.)  The definition of "simple UNION ALL" is a little simpler than
I would like --- basically the union arms can only be SELECT * FROM foo
--- but it's good enough for partitioned-table cases.
This commit is contained in:
Tom Lane
2006-02-03 21:08:49 +00:00
parent a25b1decef
commit 8b109ebf14
10 changed files with 888 additions and 388 deletions
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29
src/backend/optimizer/path/joinpath.c
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@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/optimizer/path/joinpath.c,v 1.99 2006/01/31 21:39:23 tgl Exp $
* $PostgreSQL: pgsql/src/backend/optimizer/path/joinpath.c,v 1.100 2006/02/03 21:08:49 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -20,7 +20,6 @@
#include "optimizer/cost.h"
#include "optimizer/pathnode.h"
#include "optimizer/paths.h"
#include "optimizer/prep.h"
#include "parser/parsetree.h"
#include "utils/lsyscache.h"
@ -856,8 +855,6 @@ join_before_append(PlannerInfo *root,
int childRTindex;
RelOptInfo *childrel;
Path *bestinnerjoin;
Relids joinrelids;
Relids *save_attr_needed;
RelOptInfo *this_joinrel;
List *this_restrictlist;
@ -899,27 +896,9 @@ join_before_append(PlannerInfo *root,
* in joinrels.c, it provides necessary context for the Path,
* such as properly-translated target and quals lists.
*/
joinrelids = bms_copy(joinrel->relids);
joinrelids = bms_del_member(joinrelids, parentRTindex);
joinrelids = bms_add_member(joinrelids, childRTindex);
/*
* Kluge: temporarily adjust the outer rel's attr_needed info so
* that it references the member rel instead of the appendrel.
* This is needed to build the correct targetlist for the joinrel.
*/
save_attr_needed = outerrel->attr_needed;
outerrel->attr_needed =
adjust_other_rel_attr_needed(outerrel, appinfo,
outerrel->min_attr,
outerrel->max_attr);
this_joinrel = build_join_rel(root, joinrelids, outerrel, childrel,
jointype, &this_restrictlist);
/* Now we can undo the hack on attr_needed */
pfree(outerrel->attr_needed);
outerrel->attr_needed = save_attr_needed;
this_joinrel = translate_join_rel(root, joinrel, appinfo,
outerrel, childrel, jointype,
&this_restrictlist);
/* Build Path for join and add to result list */
append_paths = lappend(append_paths,