Fix "constraint_exclusion = partition" logic so that it will also attempt

constraint exclusion on an inheritance set that is the target of an UPDATE
or DELETE query.  Per gripe from Marc Cousin.  Back-patch to 8.4 where
the feature was introduced.

4 files changed, 16 insertions, 5 deletions

diff --git a/src/backend/nodes/outfuncs.c b/src/backend/nodes/outfuncs.c
index 93aec9928ce..78cab4f534a 100644
--- a/src/backend/nodes/outfuncs.c
+++ b/src/backend/nodes/outfuncs.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/nodes/outfuncs.c,v 1.360.2.1 2009/10/06 00:55:34 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/nodes/outfuncs.c,v 1.360.2.2 2010/03/30 21:58:18 tgl Exp $
  *
  * NOTES
  *	  Every node type that can appear in stored rules' parsetrees *must*
@@ -1498,6 +1498,7 @@ _outPlannerInfo(StringInfo str, PlannerInfo *node)
 	WRITE_NODE_FIELD(sort_pathkeys);
 	WRITE_FLOAT_FIELD(total_table_pages, "%.0f");
 	WRITE_FLOAT_FIELD(tuple_fraction, "%.4f");
+	WRITE_BOOL_FIELD(hasInheritedTarget);
 	WRITE_BOOL_FIELD(hasJoinRTEs);
 	WRITE_BOOL_FIELD(hasHavingQual);
 	WRITE_BOOL_FIELD(hasPseudoConstantQuals);
diff --git a/src/backend/optimizer/plan/planner.c b/src/backend/optimizer/plan/planner.c
index 3f344b3a145..50200805a30 100644
--- a/src/backend/optimizer/plan/planner.c
+++ b/src/backend/optimizer/plan/planner.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/optimizer/plan/planner.c,v 1.256 2009/06/11 14:48:59 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/optimizer/plan/planner.c,v 1.256.2.1 2010/03/30 21:58:18 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -287,6 +287,7 @@ subquery_planner(PlannerGlobal *glob, Query *parse,
 	root->cte_plan_ids = NIL;
 	root->eq_classes = NIL;
 	root->append_rel_list = NIL;
+	root->hasInheritedTarget = false;
 
 	root->hasRecursion = hasRecursion;
 	if (hasRecursion)
@@ -663,6 +664,7 @@ inheritance_planner(PlannerInfo *root)
 								   appinfo);
 		subroot.returningLists = NIL;
 		subroot.init_plans = NIL;
+		subroot.hasInheritedTarget = true;
 		/* We needn't modify the child's append_rel_list */
 		/* There shouldn't be any OJ info to translate, as yet */
 		Assert(subroot.join_info_list == NIL);
diff --git a/src/backend/optimizer/util/plancat.c b/src/backend/optimizer/util/plancat.c
index 4f07cade68b..f7dd970e39e 100644
--- a/src/backend/optimizer/util/plancat.c
+++ b/src/backend/optimizer/util/plancat.c
@@ -9,7 +9,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/optimizer/util/plancat.c,v 1.158 2009/06/11 14:48:59 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/optimizer/util/plancat.c,v 1.158.2.1 2010/03/30 21:58:18 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -576,7 +576,10 @@ relation_excluded_by_constraints(PlannerInfo *root,
 	/* Skip the test if constraint exclusion is disabled for the rel */
 	if (constraint_exclusion == CONSTRAINT_EXCLUSION_OFF ||
 		(constraint_exclusion == CONSTRAINT_EXCLUSION_PARTITION &&
-		 rel->reloptkind != RELOPT_OTHER_MEMBER_REL))
+		 !(rel->reloptkind == RELOPT_OTHER_MEMBER_REL ||
+		   (root->hasInheritedTarget &&
+			rel->reloptkind == RELOPT_BASEREL &&
+			rel->relid == root->parse->resultRelation))))
 		return false;
 
 	/*
diff --git a/src/include/nodes/relation.h b/src/include/nodes/relation.h
index 7eb15dbeecd..5d306d7860a 100644
--- a/src/include/nodes/relation.h
+++ b/src/include/nodes/relation.h
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2009, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/nodes/relation.h,v 1.173 2009/06/11 14:49:11 momjian Exp $
+ * $PostgreSQL: pgsql/src/include/nodes/relation.h,v 1.173.2.1 2010/03/30 21:58:18 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -192,6 +192,11 @@ typedef struct PlannerInfo
 	/* These fields are used only when hasRecursion is true: */
 	int			wt_param_id;	/* PARAM_EXEC ID for the work table */
 	struct Plan *non_recursive_plan;	/* plan for non-recursive term */
+
+	/* Added at end to minimize ABI breakage in 8.4 branch: */
+
+	bool		hasInheritedTarget;	/* true if parse->resultRelation is an
+									 * inheritance child rel */
 } PlannerInfo;