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Teach planner to convert simple UNION ALL subqueries into append relations,
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.
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10 files changed

+888
-388
lines changed

10 files changed

+888
-388
lines changed

‎src/backend/optimizer/path/allpaths.c

Lines changed: 50 additions & 30 deletions
Original file line numberDiff line numberDiff line change
@@ -8,7 +8,7 @@
88
*
99
*
1010
* IDENTIFICATION
11-
* $PostgreSQL: pgsql/src/backend/optimizer/path/allpaths.c,v 1.140 2006/01/31 21:39:23 tgl Exp $
11+
* $PostgreSQL: pgsql/src/backend/optimizer/path/allpaths.c,v 1.141 2006/02/03 21:08:49 tgl Exp $
1212
*
1313
*-------------------------------------------------------------------------
1414
*/
@@ -42,6 +42,8 @@ int geqo_threshold;
4242

4343

4444
static void set_base_rel_pathlists(PlannerInfo *root);
45+
static void set_rel_pathlist(PlannerInfo *root, RelOptInfo *rel,
46+
Index rti, RangeTblEntry *rte);
4547
static void set_plain_rel_pathlist(PlannerInfo *root, RelOptInfo *rel,
4648
RangeTblEntry *rte);
4749
static void set_append_rel_pathlist(PlannerInfo *root, RelOptInfo *rel,
@@ -133,7 +135,6 @@ set_base_rel_pathlists(PlannerInfo *root)
133135
for (rti = 1; rti < root->simple_rel_array_size; rti++)
134136
{
135137
RelOptInfo *rel = root->simple_rel_array[rti];
136-
RangeTblEntry *rte;
137138

138139
/* there may be empty slots corresponding to non-baserel RTEs */
139140
if (rel == NULL)
@@ -145,33 +146,44 @@ set_base_rel_pathlists(PlannerInfo *root)
145146
if (rel->reloptkind != RELOPT_BASEREL)
146147
continue;
147148

148-
rte = rt_fetch(rti, root->parse->rtable);
149+
set_rel_pathlist(root, rel, rti,
150+
rt_fetch(rti, root->parse->rtable));
151+
}
152+
}
149153

150-
if (rte->inh)
151-
{
152-
/* It's an "append relation", process accordingly */
153-
set_append_rel_pathlist(root, rel, rti, rte);
154-
}
155-
else if (rel->rtekind == RTE_SUBQUERY)
156-
{
157-
/* Subquery --- generate a separate plan for it */
158-
set_subquery_pathlist(root, rel, rti, rte);
159-
}
160-
else if (rel->rtekind == RTE_FUNCTION)
161-
{
162-
/* RangeFunction --- generate a separate plan for it */
163-
set_function_pathlist(root, rel, rte);
164-
}
165-
else
166-
{
167-
/* Plain relation */
168-
set_plain_rel_pathlist(root, rel, rte);
169-
}
154+
/*
155+
* set_rel_pathlist
156+
* Build access paths for a base relation
157+
*/
158+
static void
159+
set_rel_pathlist(PlannerInfo *root, RelOptInfo *rel,
160+
Index rti, RangeTblEntry *rte)
161+
{
162+
if (rte->inh)
163+
{
164+
/* It's an "append relation", process accordingly */
165+
set_append_rel_pathlist(root, rel, rti, rte);
166+
}
167+
else if (rel->rtekind == RTE_SUBQUERY)
168+
{
169+
/* Subquery --- generate a separate plan for it */
170+
set_subquery_pathlist(root, rel, rti, rte);
171+
}
172+
else if (rel->rtekind == RTE_FUNCTION)
173+
{
174+
/* RangeFunction --- generate a separate plan for it */
175+
set_function_pathlist(root, rel, rte);
176+
}
177+
else
178+
{
179+
/* Plain relation */
180+
Assert(rel->rtekind == RTE_RELATION);
181+
set_plain_rel_pathlist(root, rel, rte);
182+
}
170183

171184
#ifdef OPTIMIZER_DEBUG
172-
debug_print_rel(root, rel);
185+
debug_print_rel(root, rel);
173186
#endif
174-
}
175187
}
176188

177189
/*
@@ -181,9 +193,6 @@ set_base_rel_pathlists(PlannerInfo *root)
181193
static void
182194
set_plain_rel_pathlist(PlannerInfo *root, RelOptInfo *rel, RangeTblEntry *rte)
183195
{
184-
Assert(rel->rtekind == RTE_RELATION);
185-
Assert(!rte->inh);
186-
187196
/* Mark rel with estimated output rows, width, etc */
188197
set_baserel_size_estimates(root, rel);
189198

@@ -265,6 +274,7 @@ set_append_rel_pathlist(PlannerInfo *root, RelOptInfo *rel,
265274
int childRTindex;
266275
RelOptInfo *childrel;
267276
RangeTblEntry *childrte;
277+
Path *childpath;
268278
ListCell *parentvars;
269279
ListCell *childvars;
270280

@@ -346,10 +356,20 @@ set_append_rel_pathlist(PlannerInfo *root, RelOptInfo *rel,
346356

347357
/*
348358
* Compute the child's access paths, and save the cheapest.
359+
*
360+
* It's possible that the child is itself an appendrel, in which
361+
* case we can "cut out the middleman" and just add its child
362+
* paths to our own list. (We don't try to do this earlier because
363+
* we need to apply both levels of transformation to the quals.)
349364
*/
350-
set_plain_rel_pathlist(root, childrel, childrte);
365+
set_rel_pathlist(root, childrel, childRTindex, childrte);
351366

352-
subpaths = lappend(subpaths, childrel->cheapest_total_path);
367+
childpath = childrel->cheapest_total_path;
368+
if (IsA(childpath, AppendPath))
369+
subpaths = list_concat(subpaths,
370+
((AppendPath *) childpath)->subpaths);
371+
else
372+
subpaths = lappend(subpaths, childpath);
353373

354374
/*
355375
* Propagate size information from the child back to the parent. For

‎src/backend/optimizer/path/joinpath.c

Lines changed: 4 additions & 25 deletions
Original file line numberDiff line numberDiff line change
@@ -8,7 +8,7 @@
88
*
99
*
1010
* IDENTIFICATION
11-
* $PostgreSQL: pgsql/src/backend/optimizer/path/joinpath.c,v 1.99 2006/01/31 21:39:23 tgl Exp $
11+
* $PostgreSQL: pgsql/src/backend/optimizer/path/joinpath.c,v 1.100 2006/02/03 21:08:49 tgl Exp $
1212
*
1313
*-------------------------------------------------------------------------
1414
*/
@@ -20,7 +20,6 @@
2020
#include "optimizer/cost.h"
2121
#include "optimizer/pathnode.h"
2222
#include "optimizer/paths.h"
23-
#include "optimizer/prep.h"
2423
#include "parser/parsetree.h"
2524
#include "utils/lsyscache.h"
2625

@@ -856,8 +855,6 @@ join_before_append(PlannerInfo *root,
856855
int childRTindex;
857856
RelOptInfo *childrel;
858857
Path *bestinnerjoin;
859-
Relids joinrelids;
860-
Relids *save_attr_needed;
861858
RelOptInfo *this_joinrel;
862859
List *this_restrictlist;
863860

@@ -899,27 +896,9 @@ join_before_append(PlannerInfo *root,
899896
* in joinrels.c, it provides necessary context for the Path,
900897
* such as properly-translated target and quals lists.
901898
*/
902-
joinrelids = bms_copy(joinrel->relids);
903-
joinrelids = bms_del_member(joinrelids, parentRTindex);
904-
joinrelids = bms_add_member(joinrelids, childRTindex);
905-
906-
/*
907-
* Kluge: temporarily adjust the outer rel's attr_needed info so
908-
* that it references the member rel instead of the appendrel.
909-
* This is needed to build the correct targetlist for the joinrel.
910-
*/
911-
save_attr_needed = outerrel->attr_needed;
912-
outerrel->attr_needed =
913-
adjust_other_rel_attr_needed(outerrel, appinfo,
914-
outerrel->min_attr,
915-
outerrel->max_attr);
916-
917-
this_joinrel = build_join_rel(root, joinrelids, outerrel, childrel,
918-
jointype, &this_restrictlist);
919-
920-
/* Now we can undo the hack on attr_needed */
921-
pfree(outerrel->attr_needed);
922-
outerrel->attr_needed = save_attr_needed;
899+
this_joinrel = translate_join_rel(root, joinrel, appinfo,
900+
outerrel, childrel, jointype,
901+
&this_restrictlist);
923902

924903
/* Build Path for join and add to result list */
925904
append_paths = lappend(append_paths,

‎src/backend/optimizer/plan/planner.c

Lines changed: 2 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -8,7 +8,7 @@
88
*
99
*
1010
* IDENTIFICATION
11-
* $PostgreSQL: pgsql/src/backend/optimizer/plan/planner.c,v 1.197 2006/01/31 21:39:24 tgl Exp $
11+
* $PostgreSQL: pgsql/src/backend/optimizer/plan/planner.c,v 1.198 2006/02/03 21:08:49 tgl Exp $
1212
*
1313
*-------------------------------------------------------------------------
1414
*/
@@ -222,7 +222,7 @@ subquery_planner(Query *parse, double tuple_fraction,
222222
* this query.
223223
*/
224224
parse->jointree = (FromExpr *)
225-
pull_up_subqueries(root, (Node *) parse->jointree, false);
225+
pull_up_subqueries(root, (Node *) parse->jointree, false, false);
226226

227227
/*
228228
* Detect whether any rangetable entries are RTE_JOIN kind; if not, we can

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