Fix an oversight in the original implementation of performMultipleDeletions():

the alreadyDeleted list has to be passed down through
deleteDependentObjects(), else objects that are deleted via auto/internal
dependencies don't get reported back up to performMultipleDeletions().
Depending on the visitation order, this could cause the code to try to delete
an already-deleted object, leading to strange errors in DROP OWNED (typically
"cache lookup failed for relation NNNNN" or similar).  Per bug #4289.

Patch for back branches only.  This code has recently been rewritten in HEAD,
and doesn't have this particular bug anymore.

src/backend/catalog/dependency.c

@@ -8,7 +8,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/catalog/dependency.c,v 1.69 2008/01/01 19:45:48 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/catalog/dependency.c,v 1.69.2.1 2008/07/11 16:08:50 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -130,7 +130,8 @@ static bool deleteDependentObjects(const ObjectAddress *object,
 					   DropBehavior behavior,
 					   int msglevel,
 					   ObjectAddresses *oktodelete,
-					   Relation depRel);
+					   Relation depRel,
+					   ObjectAddresses *alreadyDeleted);
 static void doDeletion(const ObjectAddress *object);
 static bool find_expr_references_walker(Node *node,
 							find_expr_references_context *context);
@@ -369,7 +370,7 @@ deleteWhatDependsOn(const ObjectAddress *object,
 	if (!deleteDependentObjects(object, objDescription,
 								DROP_CASCADE,
 								showNotices ? NOTICE : DEBUG2,
-								oktodelete, depRel))
+								oktodelete, depRel, NULL))
 		ereport(ERROR,
 				(errcode(ERRCODE_DEPENDENT_OBJECTS_STILL_EXIST),
 				 errmsg("failed to drop all objects depending on %s",
@@ -501,6 +502,9 @@ findAutoDeletableObjects(const ObjectAddress *object,
  *
  * depRel is the already-open pg_depend relation.
  *
+ * alreadyDeleted is a list to add objects to as they are deleted, or NULL
+ * if the caller doesn't need to have such a list.
+ *
  *
  * In RESTRICT mode, we perform all the deletions anyway, but ereport a message
  * and return FALSE if we find a restriction violation.  performDeletion
@@ -717,7 +721,7 @@ recursiveDeletion(const ObjectAddress *object,
 	 */
 	if (!deleteDependentObjects(object, objDescription,
 								behavior, msglevel,
-								oktodelete, depRel))
+								oktodelete, depRel, alreadyDeleted))
 		ok = false;
 
 	/*
@@ -783,6 +787,7 @@ recursiveDeletion(const ObjectAddress *object,
  *	behavior: desired drop behavior
  *	oktodelete: stuff that's AUTO-deletable
  *	depRel: already opened pg_depend relation
+ *	alreadyDeleted: optional list to add deleted objects to
  *
  * Returns TRUE if all is well, false if any problem found.
  *
@@ -798,7 +803,8 @@ deleteDependentObjects(const ObjectAddress *object,
 					   DropBehavior behavior,
 					   int msglevel,
 					   ObjectAddresses *oktodelete,
-					   Relation depRel)
+					   Relation depRel,
+					   ObjectAddresses *alreadyDeleted)
 {
 	bool		ok = true;
 	ScanKeyData key[3];
@@ -865,7 +871,8 @@ deleteDependentObjects(const ObjectAddress *object,
 									getObjectDescription(&otherObject))));
 
 				if (!recursiveDeletion(&otherObject, behavior, msglevel,
-									   object, oktodelete, depRel, NULL))
+									   object, oktodelete, depRel,
+									   alreadyDeleted))
 					ok = false;
 				break;
 			case DEPENDENCY_AUTO:
@@ -881,7 +888,8 @@ deleteDependentObjects(const ObjectAddress *object,
 								getObjectDescription(&otherObject))));
 
 				if (!recursiveDeletion(&otherObject, behavior, msglevel,
-									   object, oktodelete, depRel, NULL))
+									   object, oktodelete, depRel,
+									   alreadyDeleted))
 					ok = false;
 				break;
 			case DEPENDENCY_PIN: