diff --git a/src/backend/executor/execHHashagg.c b/src/backend/executor/execHHashagg.c
index a568aadbdb77c2ad72b29b240a658222f0b0e3b0..0953540b8659ff10739be9b2784f43de67f55f1a 100644
--- a/src/backend/executor/execHHashagg.c
+++ b/src/backend/executor/execHHashagg.c
@@ -31,7 +31,6 @@
 #include "utils/elog.h"
 #include "cdb/memquota.h"
 #include "utils/workfile_mgr.h"
-#include "utils/resource_manager.h"
 
 #include "access/hash.h"
 
@@ -89,24 +88,8 @@ typedef enum InputRecordType
 		Assert((hashtable)->mem_for_metadata > 0); \
 		Assert((hashtable)->mem_for_metadata > (hashtable)->nbuckets * OVERHEAD_PER_BUCKET); \
 		if ((hashtable)->mem_for_metadata >= (hashtable)->max_mem) \
-		{ \
-			if (IsResGroupEnabled()) \
-			{ \
-				elog(HHA_MSG_LVL, \
-					 "HashAgg: no enough operator memory for spilling: " \
-					 "operator memory is %.0f bytes, " \
-					 "current meta data is %.0f bytes; " \
-					 "the overuse is allowed in resource group mode", \
-					 (hashtable)->max_mem, \
-					 (hashtable)->mem_for_metadata); \
-			} \
-			else \
-			{ \
-				ereport(ERROR, \
-						(errcode(ERRCODE_INTERNAL_ERROR), \
-						 errmsg(ERRMSG_GP_INSUFFICIENT_STATEMENT_MEMORY))); \
-			} \
-		} \
+			ereport(ERROR, (errcode(ERRCODE_INTERNAL_ERROR), \
+				errmsg(ERRMSG_GP_INSUFFICIENT_STATEMENT_MEMORY)));\
 	} while (0)
 
 #define GET_TOTAL_USED_SIZE(hashtable) \
@@ -572,7 +555,6 @@ calcHashAggTableSizes(double memquota,	/* Memory quota in bytes. */
 					  HashAggTableSizes   *out_hats)
 {
 	double entrysize, nbuckets, nentries;
-	double orig_memquota = memquota;
 
 	/* Assume we don't need to spill */
 	bool expectSpill = false;
@@ -586,9 +568,6 @@ calcHashAggTableSizes(double memquota,	/* Memory quota in bytes. */
 	elog(HHA_MSG_LVL, "HashAgg: ngroups = %g, memquota = %g, entrysize = %g",
 		 ngroups, memquota, entrysize);
 
-	if (out_hats)
-		out_hats->memquota = memquota;
-
 	/*
 	 * When all groups can not fit in the memory, we compute
 	 * the number of batches to store spilled groups. Currently, we always
@@ -600,15 +579,6 @@ calcHashAggTableSizes(double memquota,	/* Memory quota in bytes. */
 		batchfile_mem = BATCHFILE_METADATA * (1 + nbatches);
 		expectSpill = true;
 
-		/* In resource group the memory quota could be dynamically enlarged */
-		if (IsResGroupEnabled() && memquota < batchfile_mem)
-		{
-			if (out_hats)
-				out_hats->memquota += batchfile_mem - memquota;
-
-			memquota = batchfile_mem;
-		}
-
 		/*
 		 * If the memory quota is smaller than the overhead for batch files,
 		 * return false. Note that we will always keep at most (nbatches + 1)
@@ -634,15 +604,6 @@ calcHashAggTableSizes(double memquota,	/* Memory quota in bytes. */
 	nentries = Max(nentries, gp_hashagg_groups_per_bucket);
 	entries_mem = nentries * entrywidth;
 
-	/* In resource group the memory quota could be dynamically enlarged */
-	if (IsResGroupEnabled() && memquota < entries_mem)
-	{
-		if (out_hats)
-			out_hats->memquota += 1 + entries_mem - memquota;
-
-		memquota = 1 + entries_mem;
-	}
-
 	/*
 	 * If the memory quota is smaller than the minimum number of entries
 	 * required, return false
@@ -682,15 +643,6 @@ calcHashAggTableSizes(double memquota,	/* Memory quota in bytes. */
 	nbuckets = Max(nbuckets, gp_hashagg_default_nbatches);
 	buckets_mem = nbuckets * OVERHEAD_PER_BUCKET;
 
-	/* In resource group the memory quota could be dynamically enlarged */
-	if (IsResGroupEnabled() && memquota < buckets_mem)
-	{
-		if (out_hats)
-			out_hats->memquota += buckets_mem - memquota;
-
-		memquota = buckets_mem;
-	}
-
 	/* Reserve memory for the entries + hash table */
 	memquota -= buckets_mem;
 
@@ -726,13 +678,6 @@ calcHashAggTableSizes(double memquota,	/* Memory quota in bytes. */
 		out_hats->spill = expectSpill;
 		out_hats->workmem_initial = (unsigned)(batchfile_mem);
 		out_hats->workmem_per_entry = (unsigned) entrysize;
-
-		if (IsResGroupEnabled() && out_hats->memquota > orig_memquota)
-		{
-			elog(HHA_MSG_LVL,
-				 "HashAgg: auto enlarge operator memory from %.0f to %.0f in resource group mode",
-				 out_hats->memquota, orig_memquota);
-		}
 	}
 	
 	elog(HHA_MSG_LVL, "HashAgg: nbuckets = %d, nentries = %d, nbatches = %d",
@@ -860,7 +805,7 @@ create_agg_hash_table(AggState *aggstate)
 
 	MemoryContextSwitchTo(oldcxt);
 
-	hashtable->max_mem = hashtable->hats.memquota;
+	hashtable->max_mem = 1024.0 * operatorMemKB;
 	hashtable->mem_for_metadata = sizeof(HashAggTable) +
 			hashtable->nbuckets * OVERHEAD_PER_BUCKET +
 			sizeof(GroupKeysAndAggs);
@@ -2000,26 +1945,8 @@ reCalcNumberBatches(HashAggTable *hashtable, SpillFile *spill_file)
 	
 	if (hashtable->mem_for_metadata +
 		nbatches * BATCHFILE_METADATA > hashtable->max_mem)
-	{
-		if (IsResGroupEnabled())
-		{
-			elog(HHA_MSG_LVL,
-				 "HashAgg: no enough operator memory for spilling: "
-				 "operator memory is %.0f bytes, "
-				 "current meta data is %.0f bytes, "
-				 "need %lu bytes for %u more batches; "
-				 "the overuse is allowed in resource group mode",
-				 hashtable->max_mem,
-				 hashtable->mem_for_metadata,
-				 nbatches * BATCHFILE_METADATA,
-				 nbatches);
-		}
-		else
-		{
-			ereport(ERROR, (errcode(ERRCODE_INTERNAL_ERROR),
-							ERRMSG_GP_INSUFFICIENT_STATEMENT_MEMORY));
-		}
-	}
+		ereport(ERROR, (errcode(ERRCODE_INTERNAL_ERROR),
+				 ERRMSG_GP_INSUFFICIENT_STATEMENT_MEMORY));
 	
 	hashtable->hats.nbatches = nbatches;
 }
diff --git a/src/include/executor/execHHashagg.h b/src/include/executor/execHHashagg.h
index a40fb8b1494e27c1cdadaf59392979b2ebe8518c..2ce05fcd579359828bc5191c94087586b0d0d678 100644
--- a/src/include/executor/execHHashagg.h
+++ b/src/include/executor/execHHashagg.h
@@ -126,7 +126,6 @@ typedef struct HashAggTableSizes
 	unsigned  workmem_initial;    /* Estimated work_mem bytes at #entries=0 */
 	unsigned  workmem_per_entry;  /* Additional work_mem bytes per entry */
 	bool      spill;      /* Do we expect to spill ? */
-	double    memquota;   /* Minimal required memquota */
 } HashAggTableSizes;
 
 /*
diff --git a/src/test/isolation2/expected/resgroup/resgroup_agghash_memory.out b/src/test/isolation2/expected/resgroup/resgroup_agghash_memory.out
deleted file mode 100644
index 8aaac4b7f1e383ae8ed95f082a459121429f212e..0000000000000000000000000000000000000000
--- a/src/test/isolation2/expected/resgroup/resgroup_agghash_memory.out
+++ /dev/null
@@ -1,78 +0,0 @@
--- When an agghash operator begins to spill it needs 16KB memory as meta data
--- for each batch file, when there are many batch files there might not be
--- enough operator memory for all of them, in resource queue mode the query
--- will fail with an error like below:
---
---    ERROR:  insufficient memory reserved for statement
---
--- In resource group we allow this overuse as the shared memory is designed to
--- serve this kind of overuse.
-
---start_ignore
-DROP TABLE IF EXISTS t1_agghash_mem_test;
-DROP ROLE r1_agghash_mem_test;
-DROP RESOURCE GROUP rg1_agghash_mem_test;
---end_ignore
-
-SET optimizer TO off;
-SET
-
-CREATE TABLE t1_agghash_mem_test (c1 int, c2 text) DISTRIBUTED BY (c2);
-CREATE
-INSERT INTO t1_agghash_mem_test SELECT i, i::text FROM generate_series(1,100000) i;
-INSERT 100000
-
--- we must ensure spill to be small enough but still > 0.
--- - rg1's memory quota is 682 * 1% = 6;
--- - per-xact quota is 6/3=2;
--- - spill memory is 2 * 60% = 1;
-CREATE RESOURCE GROUP rg1_agghash_mem_test WITH (cpu_rate_limit=10, memory_limit=1, memory_shared_quota=0, concurrency=3, memory_spill_ratio=60);
-CREATE
-
-CREATE ROLE r1_agghash_mem_test RESOURCE GROUP rg1_agghash_mem_test;
-CREATE
-GRANT ALL ON t1_agghash_mem_test TO r1_agghash_mem_test;
-GRANT
-
-SET gp_resgroup_memory_policy TO none;
-SET
-SET ROLE TO r1_agghash_mem_test;
-SET
-WITH a AS ( SELECT DISTINCT c2 FROM t1_agghash_mem_test INTERSECT SELECT DISTINCT c2 FROM t1_agghash_mem_test ) SELECT count(*) FROM a;
- count  
---------
- 100000 
-(1 row)
-RESET role;
-RESET
-
-SET gp_resgroup_memory_policy TO auto;
-SET
-SET ROLE TO r1_agghash_mem_test;
-SET
-WITH a AS ( SELECT DISTINCT c2 FROM t1_agghash_mem_test INTERSECT SELECT DISTINCT c2 FROM t1_agghash_mem_test ) SELECT count(*) FROM a;
- count  
---------
- 100000 
-(1 row)
-RESET role;
-RESET
-
-SET gp_resgroup_memory_policy TO eager_free;
-SET
-SET ROLE TO r1_agghash_mem_test;
-SET
-WITH a AS ( SELECT DISTINCT c2 FROM t1_agghash_mem_test INTERSECT SELECT DISTINCT c2 FROM t1_agghash_mem_test ) SELECT count(*) FROM a;
- count  
---------
- 100000 
-(1 row)
-RESET role;
-RESET
-
-DROP TABLE IF EXISTS t1_agghash_mem_test;
-DROP
-DROP ROLE r1_agghash_mem_test;
-DROP
-DROP RESOURCE GROUP rg1_agghash_mem_test;
-DROP
diff --git a/src/test/isolation2/expected/resgroup/resgroup_operator_memory.out b/src/test/isolation2/expected/resgroup/resgroup_operator_memory.out
index cf308c3fd9918a66e230dce3e4ba7bd0efd2f9a1..7be4d18e378fb0d8d63e0b53b697e9ec2ebc5bf4 100644
--- a/src/test/isolation2/expected/resgroup/resgroup_operator_memory.out
+++ b/src/test/isolation2/expected/resgroup/resgroup_operator_memory.out
@@ -23,7 +23,11 @@ CREATE
 -- we have to keep the columns provided by them in the target list, instead of
 -- composing a long SELECT c1,c2,... list we use SELECT * here, but we should
 -- not output the groupid as it changes each time.
-CREATE OR REPLACE VIEW many_ops AS SELECT * FROM gp_toolkit.gp_resgroup_config WHERE groupid=6437 UNION SELECT * FROM gp_toolkit.gp_resgroup_config WHERE groupid=6437 UNION SELECT * FROM gp_toolkit.gp_resgroup_config WHERE groupid=6437 UNION SELECT * FROM gp_toolkit.gp_resgroup_config WHERE groupid=6437 UNION SELECT * FROM gp_toolkit.gp_resgroup_config WHERE groupid=6437 UNION SELECT * FROM gp_toolkit.gp_resgroup_config WHERE groupid=6437 UNION SELECT * FROM gp_toolkit.gp_resgroup_config WHERE groupid=6437 UNION SELECT * FROM gp_toolkit.gp_resgroup_config WHERE groupid=6437 UNION SELECT * FROM gp_toolkit.gp_resgroup_config WHERE groupid=6437 UNION SELECT * FROM gp_toolkit.gp_resgroup_config WHERE groupid=6437 UNION SELECT * FROM gp_toolkit.gp_resgroup_config WHERE groupid=6437 UNION SELECT * FROM gp_toolkit.gp_resgroup_config WHERE groupid=6437 UNION SELECT * FROM gp_toolkit.gp_resgroup_config WHERE groupid=6437 UNION SELECT * FROM gp_toolkit.gp_resgroup_config WHERE groupid=6437 UNION SELECT * FROM gp_toolkit.gp_resgroup_config WHERE groupid=6437 UNION SELECT * FROM gp_toolkit.gp_resgroup_config WHERE groupid=6437 UNION SELECT * FROM gp_toolkit.gp_resgroup_config WHERE groupid=6437 UNION SELECT * FROM gp_toolkit.gp_resgroup_config WHERE groupid=6437 UNION SELECT * FROM gp_toolkit.gp_resgroup_config WHERE groupid=6437 UNION SELECT * FROM gp_toolkit.gp_resgroup_config WHERE groupid=6437 ;
+--
+-- hashagg may not work with a small operator memory, so we use UNION ALL
+-- instead of UNION to prevent putting a hashagg on top of the append node,
+-- and we use a always-false WHERE condition to prevent too much output.
+CREATE OR REPLACE VIEW many_ops AS SELECT * FROM gp_toolkit.gp_resgroup_config WHERE groupid=0 UNION ALL SELECT * FROM gp_toolkit.gp_resgroup_config WHERE groupid=0 UNION ALL SELECT * FROM gp_toolkit.gp_resgroup_config WHERE groupid=0 UNION ALL SELECT * FROM gp_toolkit.gp_resgroup_config WHERE groupid=0 UNION ALL SELECT * FROM gp_toolkit.gp_resgroup_config WHERE groupid=0 UNION ALL SELECT * FROM gp_toolkit.gp_resgroup_config WHERE groupid=0 UNION ALL SELECT * FROM gp_toolkit.gp_resgroup_config WHERE groupid=0 UNION ALL SELECT * FROM gp_toolkit.gp_resgroup_config WHERE groupid=0 UNION ALL SELECT * FROM gp_toolkit.gp_resgroup_config WHERE groupid=0 UNION ALL SELECT * FROM gp_toolkit.gp_resgroup_config WHERE groupid=0 UNION ALL SELECT * FROM gp_toolkit.gp_resgroup_config WHERE groupid=0 UNION ALL SELECT * FROM gp_toolkit.gp_resgroup_config WHERE groupid=0 UNION ALL SELECT * FROM gp_toolkit.gp_resgroup_config WHERE groupid=0 UNION ALL SELECT * FROM gp_toolkit.gp_resgroup_config WHERE groupid=0 UNION ALL SELECT * FROM gp_toolkit.gp_resgroup_config WHERE groupid=0 UNION ALL SELECT * FROM gp_toolkit.gp_resgroup_config WHERE groupid=0 UNION ALL SELECT * FROM gp_toolkit.gp_resgroup_config WHERE groupid=0 UNION ALL SELECT * FROM gp_toolkit.gp_resgroup_config WHERE groupid=0 UNION ALL SELECT * FROM gp_toolkit.gp_resgroup_config WHERE groupid=0 UNION ALL SELECT * FROM gp_toolkit.gp_resgroup_config WHERE groupid=0 ;
 CREATE
 
 -- we must ensure spill to be small enough but still > 0.
@@ -42,12 +46,6 @@ GRANT
 -- memory reserved, however in resource group mode we assign at least 100KB to
 -- each operator, no matter it is memory intensive or not.  As long as there is
 -- enough shared memory the query should be executed successfully.
---
--- some operators like HashAgg require more memory to run, the memory quota is
--- also dynamically increased to meet their minimal requirements.
---
--- note: when there is no enough operator memory there should be a warning,
--- however warnings are not displayed in isolation2 tests.
 
 --
 -- positive: there is enough global shared memory
@@ -58,10 +56,9 @@ SET
 SET ROLE TO r1_opmem_test;
 SET
 SELECT * FROM many_ops;
- groupid | groupname     | concurrency | cpu_rate_limit | memory_limit | memory_shared_quota | memory_spill_ratio | memory_auditor | cpuset 
----------+---------------+-------------+----------------+--------------+---------------------+--------------------+----------------+--------
- 6437    | default_group | 20          | 30             | 30           | 80                  | 10                 | vmtracker      | -1     
-(1 row)
+ groupid | groupname | concurrency | cpu_rate_limit | memory_limit | memory_shared_quota | memory_spill_ratio | memory_auditor | cpuset 
+---------+-----------+-------------+----------------+--------------+---------------------+--------------------+----------------+--------
+(0 rows)
 RESET role;
 RESET
 
@@ -70,10 +67,9 @@ SET
 SET ROLE TO r1_opmem_test;
 SET
 SELECT * FROM many_ops;
- groupid | groupname     | concurrency | cpu_rate_limit | memory_limit | memory_shared_quota | memory_spill_ratio | memory_auditor | cpuset 
----------+---------------+-------------+----------------+--------------+---------------------+--------------------+----------------+--------
- 6437    | default_group | 20          | 30             | 30           | 80                  | 10                 | vmtracker      | -1     
-(1 row)
+ groupid | groupname | concurrency | cpu_rate_limit | memory_limit | memory_shared_quota | memory_spill_ratio | memory_auditor | cpuset 
+---------+-----------+-------------+----------------+--------------+---------------------+--------------------+----------------+--------
+(0 rows)
 RESET role;
 RESET
 
@@ -82,10 +78,9 @@ SET
 SET ROLE TO r1_opmem_test;
 SET
 SELECT * FROM many_ops;
- groupid | groupname     | concurrency | cpu_rate_limit | memory_limit | memory_shared_quota | memory_spill_ratio | memory_auditor | cpuset 
----------+---------------+-------------+----------------+--------------+---------------------+--------------------+----------------+--------
- 6437    | default_group | 20          | 30             | 30           | 80                  | 10                 | vmtracker      | -1     
-(1 row)
+ groupid | groupname | concurrency | cpu_rate_limit | memory_limit | memory_shared_quota | memory_spill_ratio | memory_auditor | cpuset 
+---------+-----------+-------------+----------------+--------------+---------------------+--------------------+----------------+--------
+(0 rows)
 RESET role;
 RESET
 
@@ -148,10 +143,9 @@ SET
 SET ROLE TO r1_opmem_test;
 SET
 SELECT * FROM many_ops;
- groupid | groupname     | concurrency | cpu_rate_limit | memory_limit | memory_shared_quota | memory_spill_ratio | memory_auditor | cpuset 
----------+---------------+-------------+----------------+--------------+---------------------+--------------------+----------------+--------
- 6437    | default_group | 20          | 30             | 30           | 80                  | 10                 | vmtracker      | -1     
-(1 row)
+ groupid | groupname | concurrency | cpu_rate_limit | memory_limit | memory_shared_quota | memory_spill_ratio | memory_auditor | cpuset 
+---------+-----------+-------------+----------------+--------------+---------------------+--------------------+----------------+--------
+(0 rows)
 RESET role;
 RESET
 
@@ -160,10 +154,9 @@ SET
 SET ROLE TO r1_opmem_test;
 SET
 SELECT * FROM many_ops;
- groupid | groupname     | concurrency | cpu_rate_limit | memory_limit | memory_shared_quota | memory_spill_ratio | memory_auditor | cpuset 
----------+---------------+-------------+----------------+--------------+---------------------+--------------------+----------------+--------
- 6437    | default_group | 20          | 30             | 30           | 80                  | 10                 | vmtracker      | -1     
-(1 row)
+ groupid | groupname | concurrency | cpu_rate_limit | memory_limit | memory_shared_quota | memory_spill_ratio | memory_auditor | cpuset 
+---------+-----------+-------------+----------------+--------------+---------------------+--------------------+----------------+--------
+(0 rows)
 RESET role;
 RESET
 
@@ -172,10 +165,9 @@ SET
 SET ROLE TO r1_opmem_test;
 SET
 SELECT * FROM many_ops;
- groupid | groupname     | concurrency | cpu_rate_limit | memory_limit | memory_shared_quota | memory_spill_ratio | memory_auditor | cpuset 
----------+---------------+-------------+----------------+--------------+---------------------+--------------------+----------------+--------
- 6437    | default_group | 20          | 30             | 30           | 80                  | 10                 | vmtracker      | -1     
-(1 row)
+ groupid | groupname | concurrency | cpu_rate_limit | memory_limit | memory_shared_quota | memory_spill_ratio | memory_auditor | cpuset 
+---------+-----------+-------------+----------------+--------------+---------------------+--------------------+----------------+--------
+(0 rows)
 RESET role;
 RESET
 
@@ -199,10 +191,9 @@ SET
 SET ROLE TO r1_opmem_test;
 SET
 SELECT * FROM many_ops;
- groupid | groupname     | concurrency | cpu_rate_limit | memory_limit | memory_shared_quota | memory_spill_ratio | memory_auditor | cpuset 
----------+---------------+-------------+----------------+--------------+---------------------+--------------------+----------------+--------
- 6437    | default_group | 20          | 30             | 30           | 80                  | 10                 | vmtracker      | -1     
-(1 row)
+ groupid | groupname | concurrency | cpu_rate_limit | memory_limit | memory_shared_quota | memory_spill_ratio | memory_auditor | cpuset 
+---------+-----------+-------------+----------------+--------------+---------------------+--------------------+----------------+--------
+(0 rows)
 RESET role;
 RESET
 
@@ -211,10 +202,9 @@ SET
 SET ROLE TO r1_opmem_test;
 SET
 SELECT * FROM many_ops;
- groupid | groupname     | concurrency | cpu_rate_limit | memory_limit | memory_shared_quota | memory_spill_ratio | memory_auditor | cpuset 
----------+---------------+-------------+----------------+--------------+---------------------+--------------------+----------------+--------
- 6437    | default_group | 20          | 30             | 30           | 80                  | 10                 | vmtracker      | -1     
-(1 row)
+ groupid | groupname | concurrency | cpu_rate_limit | memory_limit | memory_shared_quota | memory_spill_ratio | memory_auditor | cpuset 
+---------+-----------+-------------+----------------+--------------+---------------------+--------------------+----------------+--------
+(0 rows)
 RESET role;
 RESET
 
@@ -223,10 +213,9 @@ SET
 SET ROLE TO r1_opmem_test;
 SET
 SELECT * FROM many_ops;
- groupid | groupname     | concurrency | cpu_rate_limit | memory_limit | memory_shared_quota | memory_spill_ratio | memory_auditor | cpuset 
----------+---------------+-------------+----------------+--------------+---------------------+--------------------+----------------+--------
- 6437    | default_group | 20          | 30             | 30           | 80                  | 10                 | vmtracker      | -1     
-(1 row)
+ groupid | groupname | concurrency | cpu_rate_limit | memory_limit | memory_shared_quota | memory_spill_ratio | memory_auditor | cpuset 
+---------+-----------+-------------+----------------+--------------+---------------------+--------------------+----------------+--------
+(0 rows)
 RESET role;
 RESET
 
@@ -242,10 +231,9 @@ SET
 SET ROLE TO r1_opmem_test;
 SET
 SELECT * FROM many_ops;
- groupid | groupname     | concurrency | cpu_rate_limit | memory_limit | memory_shared_quota | memory_spill_ratio | memory_auditor | cpuset 
----------+---------------+-------------+----------------+--------------+---------------------+--------------------+----------------+--------
- 6437    | default_group | 20          | 30             | 30           | 80                  | 10                 | vmtracker      | -1     
-(1 row)
+ groupid | groupname | concurrency | cpu_rate_limit | memory_limit | memory_shared_quota | memory_spill_ratio | memory_auditor | cpuset 
+---------+-----------+-------------+----------------+--------------+---------------------+--------------------+----------------+--------
+(0 rows)
 SELECT f1_opmem_test();
  f1_opmem_test 
 ---------------
@@ -259,10 +247,9 @@ SET
 SET ROLE TO r1_opmem_test;
 SET
 SELECT * FROM many_ops;
- groupid | groupname     | concurrency | cpu_rate_limit | memory_limit | memory_shared_quota | memory_spill_ratio | memory_auditor | cpuset 
----------+---------------+-------------+----------------+--------------+---------------------+--------------------+----------------+--------
- 6437    | default_group | 20          | 30             | 30           | 80                  | 10                 | vmtracker      | -1     
-(1 row)
+ groupid | groupname | concurrency | cpu_rate_limit | memory_limit | memory_shared_quota | memory_spill_ratio | memory_auditor | cpuset 
+---------+-----------+-------------+----------------+--------------+---------------------+--------------------+----------------+--------
+(0 rows)
 SELECT f1_opmem_test();
  f1_opmem_test 
 ---------------
@@ -276,10 +263,9 @@ SET
 SET ROLE TO r1_opmem_test;
 SET
 SELECT * FROM many_ops;
- groupid | groupname     | concurrency | cpu_rate_limit | memory_limit | memory_shared_quota | memory_spill_ratio | memory_auditor | cpuset 
----------+---------------+-------------+----------------+--------------+---------------------+--------------------+----------------+--------
- 6437    | default_group | 20          | 30             | 30           | 80                  | 10                 | vmtracker      | -1     
-(1 row)
+ groupid | groupname | concurrency | cpu_rate_limit | memory_limit | memory_shared_quota | memory_spill_ratio | memory_auditor | cpuset 
+---------+-----------+-------------+----------------+--------------+---------------------+--------------------+----------------+--------
+(0 rows)
 SELECT f1_opmem_test();
  f1_opmem_test 
 ---------------
diff --git a/src/test/isolation2/isolation2_resgroup_schedule b/src/test/isolation2/isolation2_resgroup_schedule
index 8ca1b1e6e0899aba04647d8d295d6dd6bc4d06be..1487958fb867f548fa4167c7a900eac2ecb6730d 100644
--- a/src/test/isolation2/isolation2_resgroup_schedule
+++ b/src/test/isolation2/isolation2_resgroup_schedule
@@ -34,7 +34,6 @@ test: resgroup/resgroup_cancel_terminate_concurrency
 # regression tests
 test: resgroup/resgroup_recreate
 test: resgroup/resgroup_operator_memory
-test: resgroup/resgroup_agghash_memory
 
 # parallel tests
 #test: resgroup/restore_default_resgroup
diff --git a/src/test/isolation2/sql/resgroup/resgroup_agghash_memory.sql b/src/test/isolation2/sql/resgroup/resgroup_agghash_memory.sql
deleted file mode 100644
index 2b7181818be4a960224b52ed41c883b5b3c6634d..0000000000000000000000000000000000000000
--- a/src/test/isolation2/sql/resgroup/resgroup_agghash_memory.sql
+++ /dev/null
@@ -1,59 +0,0 @@
--- When an agghash operator begins to spill it needs 16KB memory as meta data
--- for each batch file, when there are many batch files there might not be
--- enough operator memory for all of them, in resource queue mode the query
--- will fail with an error like below:
---
---    ERROR:  insufficient memory reserved for statement
---
--- In resource group we allow this overuse as the shared memory is designed to
--- serve this kind of overuse.
-
---start_ignore
-DROP TABLE IF EXISTS t1_agghash_mem_test;
-DROP ROLE r1_agghash_mem_test;
-DROP RESOURCE GROUP rg1_agghash_mem_test;
---end_ignore
-
-SET optimizer TO off;
-
-CREATE TABLE t1_agghash_mem_test (c1 int, c2 text) DISTRIBUTED BY (c2);
-INSERT INTO t1_agghash_mem_test SELECT i, i::text FROM generate_series(1,100000) i;
-
--- we must ensure spill to be small enough but still > 0.
--- - rg1's memory quota is 682 * 1% = 6;
--- - per-xact quota is 6/3=2;
--- - spill memory is 2 * 60% = 1;
-CREATE RESOURCE GROUP rg1_agghash_mem_test
-  WITH (cpu_rate_limit=10, memory_limit=1, memory_shared_quota=0,
-        concurrency=3, memory_spill_ratio=60);
-
-CREATE ROLE r1_agghash_mem_test RESOURCE GROUP rg1_agghash_mem_test;
-GRANT ALL ON t1_agghash_mem_test TO r1_agghash_mem_test;
-
-SET gp_resgroup_memory_policy TO none;
-SET ROLE TO r1_agghash_mem_test;
-WITH a AS (
-	SELECT DISTINCT c2 FROM t1_agghash_mem_test INTERSECT
-	SELECT DISTINCT c2 FROM t1_agghash_mem_test
-) SELECT count(*) FROM a;
-RESET role;
-
-SET gp_resgroup_memory_policy TO auto;
-SET ROLE TO r1_agghash_mem_test;
-WITH a AS (
-	SELECT DISTINCT c2 FROM t1_agghash_mem_test INTERSECT
-	SELECT DISTINCT c2 FROM t1_agghash_mem_test
-) SELECT count(*) FROM a;
-RESET role;
-
-SET gp_resgroup_memory_policy TO eager_free;
-SET ROLE TO r1_agghash_mem_test;
-WITH a AS (
-	SELECT DISTINCT c2 FROM t1_agghash_mem_test INTERSECT
-	SELECT DISTINCT c2 FROM t1_agghash_mem_test
-) SELECT count(*) FROM a;
-RESET role;
-
-DROP TABLE IF EXISTS t1_agghash_mem_test;
-DROP ROLE r1_agghash_mem_test;
-DROP RESOURCE GROUP rg1_agghash_mem_test;
diff --git a/src/test/isolation2/sql/resgroup/resgroup_operator_memory.sql b/src/test/isolation2/sql/resgroup/resgroup_operator_memory.sql
index 574303a0cf3d68867da7bab2dacfcccc76a7cf5f..10cfad537ff17eabce3a5288b9816d09ed5a1831 100644
--- a/src/test/isolation2/sql/resgroup/resgroup_operator_memory.sql
+++ b/src/test/isolation2/sql/resgroup/resgroup_operator_memory.sql
@@ -23,27 +23,31 @@ $$ LANGUAGE plpythonu;
 -- we have to keep the columns provided by them in the target list, instead of
 -- composing a long SELECT c1,c2,... list we use SELECT * here, but we should
 -- not output the groupid as it changes each time.
+--
+-- hashagg may not work with a small operator memory, so we use UNION ALL
+-- instead of UNION to prevent putting a hashagg on top of the append node,
+-- and we use a always-false WHERE condition to prevent too much output.
 CREATE OR REPLACE VIEW many_ops AS
-      SELECT * FROM gp_toolkit.gp_resgroup_config WHERE groupid=6437
-UNION SELECT * FROM gp_toolkit.gp_resgroup_config WHERE groupid=6437
-UNION SELECT * FROM gp_toolkit.gp_resgroup_config WHERE groupid=6437
-UNION SELECT * FROM gp_toolkit.gp_resgroup_config WHERE groupid=6437
-UNION SELECT * FROM gp_toolkit.gp_resgroup_config WHERE groupid=6437
-UNION SELECT * FROM gp_toolkit.gp_resgroup_config WHERE groupid=6437
-UNION SELECT * FROM gp_toolkit.gp_resgroup_config WHERE groupid=6437
-UNION SELECT * FROM gp_toolkit.gp_resgroup_config WHERE groupid=6437
-UNION SELECT * FROM gp_toolkit.gp_resgroup_config WHERE groupid=6437
-UNION SELECT * FROM gp_toolkit.gp_resgroup_config WHERE groupid=6437
-UNION SELECT * FROM gp_toolkit.gp_resgroup_config WHERE groupid=6437
-UNION SELECT * FROM gp_toolkit.gp_resgroup_config WHERE groupid=6437
-UNION SELECT * FROM gp_toolkit.gp_resgroup_config WHERE groupid=6437
-UNION SELECT * FROM gp_toolkit.gp_resgroup_config WHERE groupid=6437
-UNION SELECT * FROM gp_toolkit.gp_resgroup_config WHERE groupid=6437
-UNION SELECT * FROM gp_toolkit.gp_resgroup_config WHERE groupid=6437
-UNION SELECT * FROM gp_toolkit.gp_resgroup_config WHERE groupid=6437
-UNION SELECT * FROM gp_toolkit.gp_resgroup_config WHERE groupid=6437
-UNION SELECT * FROM gp_toolkit.gp_resgroup_config WHERE groupid=6437
-UNION SELECT * FROM gp_toolkit.gp_resgroup_config WHERE groupid=6437
+          SELECT * FROM gp_toolkit.gp_resgroup_config WHERE groupid=0
+UNION ALL SELECT * FROM gp_toolkit.gp_resgroup_config WHERE groupid=0
+UNION ALL SELECT * FROM gp_toolkit.gp_resgroup_config WHERE groupid=0
+UNION ALL SELECT * FROM gp_toolkit.gp_resgroup_config WHERE groupid=0
+UNION ALL SELECT * FROM gp_toolkit.gp_resgroup_config WHERE groupid=0
+UNION ALL SELECT * FROM gp_toolkit.gp_resgroup_config WHERE groupid=0
+UNION ALL SELECT * FROM gp_toolkit.gp_resgroup_config WHERE groupid=0
+UNION ALL SELECT * FROM gp_toolkit.gp_resgroup_config WHERE groupid=0
+UNION ALL SELECT * FROM gp_toolkit.gp_resgroup_config WHERE groupid=0
+UNION ALL SELECT * FROM gp_toolkit.gp_resgroup_config WHERE groupid=0
+UNION ALL SELECT * FROM gp_toolkit.gp_resgroup_config WHERE groupid=0
+UNION ALL SELECT * FROM gp_toolkit.gp_resgroup_config WHERE groupid=0
+UNION ALL SELECT * FROM gp_toolkit.gp_resgroup_config WHERE groupid=0
+UNION ALL SELECT * FROM gp_toolkit.gp_resgroup_config WHERE groupid=0
+UNION ALL SELECT * FROM gp_toolkit.gp_resgroup_config WHERE groupid=0
+UNION ALL SELECT * FROM gp_toolkit.gp_resgroup_config WHERE groupid=0
+UNION ALL SELECT * FROM gp_toolkit.gp_resgroup_config WHERE groupid=0
+UNION ALL SELECT * FROM gp_toolkit.gp_resgroup_config WHERE groupid=0
+UNION ALL SELECT * FROM gp_toolkit.gp_resgroup_config WHERE groupid=0
+UNION ALL SELECT * FROM gp_toolkit.gp_resgroup_config WHERE groupid=0
 ;
 
 -- we must ensure spill to be small enough but still > 0.
@@ -61,12 +65,6 @@ GRANT ALL ON many_ops TO r1_opmem_test;
 -- memory reserved, however in resource group mode we assign at least 100KB to
 -- each operator, no matter it is memory intensive or not.  As long as there is
 -- enough shared memory the query should be executed successfully.
---
--- some operators like HashAgg require more memory to run, the memory quota is
--- also dynamically increased to meet their minimal requirements.
---
--- note: when there is no enough operator memory there should be a warning,
--- however warnings are not displayed in isolation2 tests.
 
 --
 -- positive: there is enough global shared memory