diff --git a/src/backend/optimizer/util/clauses.c b/src/backend/optimizer/util/clauses.c
index e525ba6..e4a107e 100644
*** a/src/backend/optimizer/util/clauses.c
--- b/src/backend/optimizer/util/clauses.c
*************** count_agg_clauses_walker(Node *node, Agg
*** 529,535 ****
  		 * pass-by-reference then we have to add the estimated size of the
  		 * value itself, plus palloc overhead.
  		 */
! 		if (!get_typbyval(aggtranstype))
  		{
  			int32		aggtranstypmod;
  			int32		avgwidth;
--- 529,543 ----
  		 * pass-by-reference then we have to add the estimated size of the
  		 * value itself, plus palloc overhead.
  		 */
! 		if (aggref->aggfnoid == ARRAY_AGG_OID)
! 		{
! 			/*
! 			 * Since array_agg consumes much more memory than other aggregate
! 			 * functions, we made a special case for it.
! 			 */
! 			counts->transitionSpace += ALLOCSET_DEFAULT_INITSIZE;
! 		}
! 		else if (!get_typbyval(aggtranstype))
  		{
  			int32		aggtranstypmod;
  			int32		avgwidth;
diff --git a/src/include/catalog/pg_proc.h b/src/include/catalog/pg_proc.h
index 564917d..0564627 100644
*** a/src/include/catalog/pg_proc.h
--- b/src/include/catalog/pg_proc.h
*************** DATA(insert OID = 2334 (  array_agg_fina
*** 1046,1051 ****
--- 1046,1052 ----
  DESCR("array_agg final function");
  DATA(insert OID = 2335 (  array_agg		   PGNSP PGUID 12 1 0 0 t f f f f i 1 0 2277 "2283" _null_ _null_ _null_ _null_ aggregate_dummy _null_ _null_ _null_ ));
  DESCR("concatenate aggregate input into an array");
+ #define ARRAY_AGG_OID 2335
  
  DATA(insert OID = 760 (  smgrin			   PGNSP PGUID 12 1 0 0 f f f t f s 1 0 210 "2275" _null_ _null_ _null_ _null_	smgrin _null_ _null_ _null_ ));
  DESCR("I/O");