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.

1 files changed, 6 insertions, 15 deletions

diff --git a/src/backend/utils/cache/plancache.c b/src/backend/utils/cache/plancache.c
index 43297281f5f..2f52ed7a8cc 100644
--- a/src/backend/utils/cache/plancache.c
+++ b/src/backend/utils/cache/plancache.c
@@ -33,7 +33,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/utils/cache/plancache.c,v 1.11 2007/09/20 17:56:31 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/utils/cache/plancache.c,v 1.12 2007/10/11 18:05:27 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -921,26 +921,17 @@ PlanCacheCallback(Datum arg, Oid relid)
 			foreach(lc2, plan->stmt_list)
 			{
 				PlannedStmt *plannedstmt = (PlannedStmt *) lfirst(lc2);
-				ListCell   *lc3;
 
 				Assert(!IsA(plannedstmt, Query));
 				if (!IsA(plannedstmt, PlannedStmt))
 					continue;			/* Ignore utility statements */
-				foreach(lc3, plannedstmt->rtable)
+				if ((relid == InvalidOid) ? plannedstmt->relationOids != NIL :
+					list_member_oid(plannedstmt->relationOids, relid))
 				{
-					RangeTblEntry *rte = (RangeTblEntry *) lfirst(lc3);
-
-					if (rte->rtekind != RTE_RELATION)
-						continue;
-					if (relid == rte->relid || relid == InvalidOid)
-					{
-						/* Invalidate the plan! */
-						plan->dead = true;
-						break;		/* out of rangetable scan */
-					}
-				}
-				if (plan->dead)
+					/* Invalidate the plan! */
+					plan->dead = true;
 					break;			/* out of stmt_list scan */
+				}
 			}
 		}
 		else