Fix the plan-invalidation mechanism to treat regclass constants that refer to

a relation as a reason to invalidate a plan when the relation changes.  This
handles scenarios such as dropping/recreating a sequence that is referenced by
nextval('seq') in a cached plan.  Rather than teach plancache.c all about
digging through plan trees to find regclass Consts, we charge the planner's
setrefs.c with making a list of the relation OIDs on which each plan depends.
That way the list can be built cheaply during a plan tree traversal that has
to happen anyway.  Per bug #3662 and subsequent discussion.

3 files changed, 9 insertions, 4 deletions

diff --git a/src/include/nodes/plannodes.h b/src/include/nodes/plannodes.h
index 992b47f58d8..9b6c6372846 100644
--- a/src/include/nodes/plannodes.h
+++ b/src/include/nodes/plannodes.h
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/nodes/plannodes.h,v 1.95 2007/09/20 17:56:32 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/nodes/plannodes.h,v 1.96 2007/10/11 18:05:27 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -70,6 +70,8 @@ typedef struct PlannedStmt
 
 	List	   *rowMarks;		/* a list of RowMarkClause's */
 
+	List	   *relationOids;	/* OIDs of relations the plan depends on */
+
 	int			nParamExec;		/* number of PARAM_EXEC Params used */
 } PlannedStmt;
 
diff --git a/src/include/nodes/relation.h b/src/include/nodes/relation.h
index 32c699b6de6..38903520222 100644
--- a/src/include/nodes/relation.h
+++ b/src/include/nodes/relation.h
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/nodes/relation.h,v 1.146 2007/09/20 17:56:32 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/nodes/relation.h,v 1.147 2007/10/11 18:05:27 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -72,6 +72,8 @@ typedef struct PlannerGlobal
 
 	List	   *finalrtable;	/* "flat" rangetable for executor */
 
+	List	   *relationOids;	/* OIDs of relations the plan depends on */
+
 	bool		transientPlan;	/* redo plan when TransactionXmin changes? */
 } PlannerGlobal;
 
diff --git a/src/include/optimizer/planmain.h b/src/include/optimizer/planmain.h
index 4673d53098f..43769c71e11 100644
--- a/src/include/optimizer/planmain.h
+++ b/src/include/optimizer/planmain.h
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/optimizer/planmain.h,v 1.102 2007/10/04 20:44:47 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/optimizer/planmain.h,v 1.103 2007/10/11 18:05:27 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -96,7 +96,8 @@ extern RestrictInfo *build_implied_join_equality(Oid opno,
 extern Plan *set_plan_references(PlannerGlobal *glob,
 								 Plan *plan,
 								 List *rtable);
-extern List *set_returning_clause_references(List *rlist,
+extern List *set_returning_clause_references(PlannerGlobal *glob,
+								List *rlist,
 								Plan *topplan,
 								Index resultRelation);
 extern void fix_opfuncids(Node *node);