This patch will ensure that the hash table iteration performed by

bmomjian · bmomjian · commit c5c1cc3bf864 · 2005-05-11T18:05:37.000Z
AtCommit_Portals is restarted when a portal is deleted. This is
necessary since the deletion of a portal may cause the deletion of
another which on rare occations may cause the iterator to return a
deleted portal an thus a renewed attempt delete.

Thomas Hallgren
diff --git a/src/backend/utils/mmgr/portalmem.c b/src/backend/utils/mmgr/portalmem.c
@@ -12,7 +12,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/utils/mmgr/portalmem.c,v 1.78 2005/04/11 19:51:15 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/utils/mmgr/portalmem.c,v 1.79 2005/05/11 18:05:37 momjian Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -475,12 +475,6 @@ CommitHoldablePortals(void)
  *
  * Remove all non-holdable portals created in this transaction.
  * Portals remaining from prior transactions should be left untouched.
- *
- * XXX This assumes that portals can be deleted in a random order, ie,
- * no portal has a reference to any other (at least not one that will be
- * exercised during deletion).	I think this is okay at the moment, but
- * we've had bugs of that ilk in the past.  Keep a close eye on cursor
- * references...
  */
 void
 AtCommit_Portals(void)
@@ -516,6 +510,9 @@ AtCommit_Portals(void)
 
 		/* Zap all non-holdable portals */
 		PortalDrop(portal, true);
+
+		/* Restart the iteration */
+		hash_seq_init(&status, PortalHashTable);
 	}
 }
 

Original file line number	Diff line number	Diff line change
`@@ -12,7 +12,7 @@`
`12`	`12`	`* Portions Copyright (c) 1994, Regents of the University of California`
`13`	`13`	`*`
`14`	`14`	`* IDENTIFICATION`
`15`		`- * $PostgreSQL: pgsql/src/backend/utils/mmgr/portalmem.c,v 1.78 2005/04/11 19:51:15 tgl Exp $`
	`15`	`+ * $PostgreSQL: pgsql/src/backend/utils/mmgr/portalmem.c,v 1.79 2005/05/11 18:05:37 momjian Exp $`
`16`	`16`	`*`
`17`	`17`	`*-------------------------------------------------------------------------`
`18`	`18`	`*/`
`@@ -475,12 +475,6 @@ CommitHoldablePortals(void)`
`475`	`475`	`*`
`476`	`476`	`* Remove all non-holdable portals created in this transaction.`
`477`	`477`	`* Portals remaining from prior transactions should be left untouched.`
`478`		`- *`
`479`		`- * XXX This assumes that portals can be deleted in a random order, ie,`
`480`		`- * no portal has a reference to any other (at least not one that will be`
`481`		`- * exercised during deletion). I think this is okay at the moment, but`
`482`		`- * we've had bugs of that ilk in the past. Keep a close eye on cursor`
`483`		`- * references...`
`484`	`478`	`*/`
`485`	`479`	`void`
`486`	`480`	`AtCommit_Portals(void)`
`@@ -516,6 +510,9 @@ AtCommit_Portals(void)`
`516`	`510`
`517`	`511`	`/* Zap all non-holdable portals */`
`518`	`512`	`PortalDrop(portal, true);`
	`513`	`+`
	`514`	`+ /* Restart the iteration */`
	`515`	`+ hash_seq_init(&status, PortalHashTable);`
`519`	`516`	`}`
`520`	`517`	`}`
`521`	`518`