diff --git a/src/backend/executor/nodeAgg.c b/src/backend/executor/nodeAgg.c
index b06e1c1..e0288ba 100644
*** a/src/backend/executor/nodeAgg.c
--- b/src/backend/executor/nodeAgg.c
*************** advance_transition_function(AggState *ag
*** 791,798 ****
  
  	/*
  	 * If pass-by-ref datatype, must copy the new value into aggcontext and
! 	 * pfree the prior transValue.  But if transfn returned a pointer to its
! 	 * first input, we don't need to do anything.
  	 */
  	if (!pertrans->transtypeByVal &&
  		DatumGetPointer(newVal) != DatumGetPointer(pergroupstate->transValue))
--- 791,800 ----
  
  	/*
  	 * If pass-by-ref datatype, must copy the new value into aggcontext and
! 	 * free the prior transValue.  But if transfn returned a pointer to its
! 	 * first input, we don't need to do anything.  Also, if transfn returned a
! 	 * pointer to a R/W expanded object that is already a child of the
! 	 * aggcontext, assume we can adopt that value without copying it.
  	 */
  	if (!pertrans->transtypeByVal &&
  		DatumGetPointer(newVal) != DatumGetPointer(pergroupstate->transValue))
*************** advance_transition_function(AggState *ag
*** 800,811 ****
  		if (!fcinfo->isnull)
  		{
  			MemoryContextSwitchTo(aggstate->aggcontexts[aggstate->current_set]->ecxt_per_tuple_memory);
! 			newVal = datumCopy(newVal,
! 							   pertrans->transtypeByVal,
! 							   pertrans->transtypeLen);
  		}
  		if (!pergroupstate->transValueIsNull)
! 			pfree(DatumGetPointer(pergroupstate->transValue));
  	}
  
  	pergroupstate->transValue = newVal;
--- 802,826 ----
  		if (!fcinfo->isnull)
  		{
  			MemoryContextSwitchTo(aggstate->aggcontexts[aggstate->current_set]->ecxt_per_tuple_memory);
! 			if (DatumIsReadWriteExpandedObject(newVal,
! 											   false,
! 											   pertrans->transtypeLen) &&
! 				MemoryContextGetParent(DatumGetEOHP(newVal)->eoh_context) == CurrentMemoryContext)
! 				 /* do nothing */ ;
! 			else
! 				newVal = datumCopy(newVal,
! 								   pertrans->transtypeByVal,
! 								   pertrans->transtypeLen);
  		}
  		if (!pergroupstate->transValueIsNull)
! 		{
! 			if (DatumIsReadWriteExpandedObject(pergroupstate->transValue,
! 											   false,
! 											   pertrans->transtypeLen))
! 				DeleteExpandedObject(pergroupstate->transValue);
! 			else
! 				pfree(DatumGetPointer(pergroupstate->transValue));
! 		}
  	}
  
  	pergroupstate->transValue = newVal;
*************** advance_combine_function(AggState *aggst
*** 1053,1060 ****
  
  	/*
  	 * If pass-by-ref datatype, must copy the new value into aggcontext and
! 	 * pfree the prior transValue.  But if the combine function returned a
! 	 * pointer to its first input, we don't need to do anything.
  	 */
  	if (!pertrans->transtypeByVal &&
  		DatumGetPointer(newVal) != DatumGetPointer(pergroupstate->transValue))
--- 1068,1078 ----
  
  	/*
  	 * If pass-by-ref datatype, must copy the new value into aggcontext and
! 	 * free the prior transValue.  But if the combine function returned a
! 	 * pointer to its first input, we don't need to do anything.  Also, if the
! 	 * combine function returned a pointer to a R/W expanded object that is
! 	 * already a child of the aggcontext, assume we can adopt that value
! 	 * without copying it.
  	 */
  	if (!pertrans->transtypeByVal &&
  		DatumGetPointer(newVal) != DatumGetPointer(pergroupstate->transValue))
*************** advance_combine_function(AggState *aggst
*** 1062,1073 ****
  		if (!fcinfo->isnull)
  		{
  			MemoryContextSwitchTo(aggstate->aggcontexts[aggstate->current_set]->ecxt_per_tuple_memory);
! 			newVal = datumCopy(newVal,
! 							   pertrans->transtypeByVal,
! 							   pertrans->transtypeLen);
  		}
  		if (!pergroupstate->transValueIsNull)
! 			pfree(DatumGetPointer(pergroupstate->transValue));
  	}
  
  	pergroupstate->transValue = newVal;
--- 1080,1104 ----
  		if (!fcinfo->isnull)
  		{
  			MemoryContextSwitchTo(aggstate->aggcontexts[aggstate->current_set]->ecxt_per_tuple_memory);
! 			if (DatumIsReadWriteExpandedObject(newVal,
! 											   false,
! 											   pertrans->transtypeLen) &&
! 				MemoryContextGetParent(DatumGetEOHP(newVal)->eoh_context) == CurrentMemoryContext)
! 				 /* do nothing */ ;
! 			else
! 				newVal = datumCopy(newVal,
! 								   pertrans->transtypeByVal,
! 								   pertrans->transtypeLen);
  		}
  		if (!pergroupstate->transValueIsNull)
! 		{
! 			if (DatumIsReadWriteExpandedObject(pergroupstate->transValue,
! 											   false,
! 											   pertrans->transtypeLen))
! 				DeleteExpandedObject(pergroupstate->transValue);
! 			else
! 				pfree(DatumGetPointer(pergroupstate->transValue));
! 		}
  	}
  
  	pergroupstate->transValue = newVal;
diff --git a/src/backend/utils/adt/array_userfuncs.c b/src/backend/utils/adt/array_userfuncs.c
index 1ef1500..8d6fa41 100644
*** a/src/backend/utils/adt/array_userfuncs.c
--- b/src/backend/utils/adt/array_userfuncs.c
*************** static Datum array_position_common(Funct
*** 32,37 ****
--- 32,41 ----
   * Caution: if the input is a read/write pointer, this returns the input
   * argument; so callers must be sure that their changes are "safe", that is
   * they cannot leave the array in a corrupt state.
+  *
+  * If we're being called as an aggregate function, make sure any newly-made
+  * expanded array is allocated in the aggregate state context, so as to save
+  * copying operations.
   */
  static ExpandedArrayHeader *
  fetch_array_arg_replace_nulls(FunctionCallInfo fcinfo, int argno)
*************** fetch_array_arg_replace_nulls(FunctionCa
*** 39,44 ****
--- 43,49 ----
  	ExpandedArrayHeader *eah;
  	Oid			element_type;
  	ArrayMetaState *my_extra;
+ 	MemoryContext resultcxt;
  
  	/* If first time through, create datatype cache struct */
  	my_extra = (ArrayMetaState *) fcinfo->flinfo->fn_extra;
*************** fetch_array_arg_replace_nulls(FunctionCa
*** 51,60 ****
--- 56,72 ----
  		fcinfo->flinfo->fn_extra = my_extra;
  	}
  
+ 	/* Figure out which context we want the result in */
+ 	if (!AggCheckCallContext(fcinfo, &resultcxt))
+ 		resultcxt = CurrentMemoryContext;
+ 
  	/* Now collect the array value */
  	if (!PG_ARGISNULL(argno))
  	{
+ 		MemoryContext oldcxt = MemoryContextSwitchTo(resultcxt);
+ 
  		eah = PG_GETARG_EXPANDED_ARRAYX(argno, my_extra);
+ 		MemoryContextSwitchTo(oldcxt);
  	}
  	else
  	{
*************** fetch_array_arg_replace_nulls(FunctionCa
*** 72,78 ****
  					 errmsg("input data type is not an array")));
  
  		eah = construct_empty_expanded_array(element_type,
! 											 CurrentMemoryContext,
  											 my_extra);
  	}
  
--- 84,90 ----
  					 errmsg("input data type is not an array")));
  
  		eah = construct_empty_expanded_array(element_type,
! 											 resultcxt,
  											 my_extra);
  	}