Index: src/backend/executor/nodeAgg.c
===================================================================
RCS file: /cvsroot/pgsql/src/backend/executor/nodeAgg.c,v
retrieving revision 1.167
diff -c -r1.167 nodeAgg.c
*** src/backend/executor/nodeAgg.c	17 Jun 2009 16:05:34 -0000	1.167
--- src/backend/executor/nodeAgg.c	23 Jul 2009 19:19:33 -0000
***************
*** 55,60 ****
--- 55,62 ----
   *	  in either case its value need not be preserved.  See int8inc() for an
   *	  example.	Notice that advance_transition_function() is coded to avoid a
   *	  data copy step when the previous transition value pointer is returned.
+  *	  Also, some transition functions make use of the aggcontext to store
+  *	  working state.
   *
   *
   * Portions Copyright (c) 1996-2009, PostgreSQL Global Development Group
***************
*** 273,290 ****
  		}
  
  		/*
- 		 * If we are reinitializing after a group boundary, we have to free
- 		 * any prior transValue to avoid memory leakage.  We must check not
- 		 * only the isnull flag but whether the pointer is NULL; since
- 		 * pergroupstate is initialized with palloc0, the initial condition
- 		 * has isnull = 0 and null pointer.
- 		 */
- 		if (!peraggstate->transtypeByVal &&
- 			!pergroupstate->transValueIsNull &&
- 			DatumGetPointer(pergroupstate->transValue) != NULL)
- 			pfree(DatumGetPointer(pergroupstate->transValue));
- 
- 		/*
  		 * (Re)set transValue to the initial value.
  		 *
  		 * Note that when the initial value is pass-by-ref, we must copy it
--- 275,280 ----
***************
*** 911,920 ****
  		}
  
  		/*
! 		 * Clear the per-output-tuple context for each group
  		 */
  		ResetExprContext(econtext);
  
  		/*
  		 * Initialize working state for a new input tuple group
  		 */
--- 901,915 ----
  		}
  
  		/*
! 		 * Clear the per-output-tuple context for each group, as well as
! 		 * aggcontext (which contains any pass-by-ref transvalues of the
! 		 * old group).  We also clear any child contexts of the aggcontext;
! 		 * some aggregate functions store working state in such contexts.
  		 */
  		ResetExprContext(econtext);
  
+ 		MemoryContextResetAndDeleteChildren(aggstate->aggcontext);
+ 
  		/*
  		 * Initialize working state for a new input tuple group
  		 */
***************
*** 1234,1240 ****
  	 * structures and transition values.  NOTE: the details of what is stored
  	 * in aggcontext and what is stored in the regular per-query memory
  	 * context are driven by a simple decision: we want to reset the
! 	 * aggcontext in ExecReScanAgg to recover no-longer-wanted space.
  	 */
  	aggstate->aggcontext =
  		AllocSetContextCreate(CurrentMemoryContext,
--- 1229,1236 ----
  	 * structures and transition values.  NOTE: the details of what is stored
  	 * in aggcontext and what is stored in the regular per-query memory
  	 * context are driven by a simple decision: we want to reset the
! 	 * aggcontext at group boundaries (if not hashing) and in ExecReScanAgg
! 	 * to recover no-longer-wanted space.
  	 */
  	aggstate->aggcontext =
  		AllocSetContextCreate(CurrentMemoryContext,
Index: src/backend/utils/adt/array_userfuncs.c
===================================================================
RCS file: /cvsroot/pgsql/src/backend/utils/adt/array_userfuncs.c,v
retrieving revision 1.31
diff -c -r1.31 array_userfuncs.c
*** src/backend/utils/adt/array_userfuncs.c	20 Jun 2009 18:45:28 -0000	1.31
--- src/backend/utils/adt/array_userfuncs.c	23 Jul 2009 19:19:33 -0000
***************
*** 539,545 ****
  
  	/*
  	 * Make the result.  We cannot release the ArrayBuildState because
! 	 * sometimes aggregate final functions are re-executed.
  	 */
  	result = makeMdArrayResult(state, 1, dims, lbs,
  							   CurrentMemoryContext,
--- 539,547 ----
  
  	/*
  	 * Make the result.  We cannot release the ArrayBuildState because
! 	 * sometimes aggregate final functions are re-executed.  Rather, it
! 	 * is nodeAgg.c's responsibility to reset the aggcontext when it's
! 	 * safe to do so.
  	 */
  	result = makeMdArrayResult(state, 1, dims, lbs,
  							   CurrentMemoryContext,