Index: trigger.c
===================================================================
RCS file: /cvsroot/pgsql/src/backend/commands/trigger.c,v
retrieving revision 1.210.2.1
diff -c -r1.210.2.1 trigger.c
*** trigger.c	25 Jan 2007 04:17:56 -0000	1.210.2.1
--- trigger.c	1 Jul 2007 17:26:52 -0000
***************
*** 2766,2771 ****
--- 2766,2789 ----
  		afterTriggers->state_stack[my_level] = NULL;
  		Assert(afterTriggers->query_depth ==
  			   afterTriggers->depth_stack[my_level]);
+ 		/*
+ 		 * It's entirely possible that the subxact created an event_cxt but
+ 		 * there is not anything left in it (because all the triggers were
+ 		 * fired at end-of-statement).  If so, we should release the context
+ 		 * to prevent memory leakage in a long sequence of subtransactions.
+ 		 * We can detect whether there's anything of use in the context by
+ 		 * seeing if anything was added to the global events list since
+ 		 * subxact start.  (This test doesn't catch every case where the
+ 		 * context is deletable; for instance maybe the only additions were
+ 		 * from a sub-sub-xact.  But it handles the common case.)
+ 		 */
+ 		if (afterTriggers->cxt_stack[my_level] &&
+ 			afterTriggers->events.tail == afterTriggers->events_stack[my_level].tail)
+ 		{
+ 			MemoryContextDelete(afterTriggers->cxt_stack[my_level]);
+ 			/* avoid double delete if abort later */
+ 			afterTriggers->cxt_stack[my_level] = NULL;
+ 		}
  	}
  	else
  	{