diff --git a/src/common/backend/catalog/system_views.sql b/src/common/backend/catalog/system_views.sql
index 397ec772caf7af181847900aeb6341202d128b7c..c6a73312f5346693d684ea1c24b622468db51406 100644
--- a/src/common/backend/catalog/system_views.sql
+++ b/src/common/backend/catalog/system_views.sql
@@ -1764,25 +1764,28 @@ CREATE CAST (RAW AS TEXT) WITH FUNCTION rawtohex(raw) AS IMPLICIT;
 CREATE CAST (BLOB AS RAW) WITHOUT FUNCTION AS IMPLICIT;
 CREATE CAST (RAW AS BLOB) WITHOUT FUNCTION AS IMPLICIT;
 
+CREATE CAST (TEXT AS CLOB) WITHOUT FUNCTION AS IMPLICIT;
+CREATE CAST (CLOB AS TEXT) WITHOUT FUNCTION AS IMPLICIT;
+
 /* text to clob */
 CREATE OR REPLACE FUNCTION to_clob(TEXT)
-RETURNS TEXT
+RETURNS CLOB
 AS $$ select $1 $$
 LANGUAGE SQL IMMUTABLE STRICT NOT FENCED;
 
 /* char to clob */
 CREATE OR REPLACE FUNCTION to_clob(CHAR)
-RETURNS TEXT
+RETURNS CLOB
 AS $$ select CAST($1 AS TEXT) $$
 LANGUAGE SQL IMMUTABLE STRICT NOT FENCED;
 
 CREATE OR REPLACE FUNCTION to_clob(VARCHAR)
-RETURNS TEXT
+RETURNS CLOB
 AS $$ select CAST($1 AS TEXT) $$
 LANGUAGE SQL IMMUTABLE STRICT NOT FENCED;
 
 CREATE OR REPLACE FUNCTION to_clob(NVARCHAR2)
-RETURNS TEXT
+RETURNS CLOB
 AS $$ select CAST($1 AS TEXT) $$
 LANGUAGE SQL IMMUTABLE STRICT NOT FENCED;
 
diff --git a/src/common/backend/nodes/makefuncs.cpp b/src/common/backend/nodes/makefuncs.cpp
index d20f2511d1e5801fae08043f07d6d534cd880fa0..5eaf948c98785fc4e9f96afb56c6affdf205601a 100755
--- a/src/common/backend/nodes/makefuncs.cpp
+++ b/src/common/backend/nodes/makefuncs.cpp
@@ -449,18 +449,6 @@ TypeName* makeTypeName(char* typnam)
     return makeTypeNameFromNameList(list_make1(makeString(typnam)));
 }
 
-static void alter_clob_to_text(List* names)
-{
-    if (list_length(names) != 1) {
-        return;
-    } else {
-        char* type_name = strVal(linitial(names));
-        if (strcmp(type_name, "clob") == 0) {
-            errno_t rc = strcpy_s(type_name, sizeof("clob"), "text");
-            securec_check_c(rc, "\0", "\0");
-        }
-    }
-}
 /*
  * makeTypeNameFromNameList -
  *	build a TypeName node for a String list representing a qualified name.
@@ -470,7 +458,6 @@ static void alter_clob_to_text(List* names)
 TypeName* makeTypeNameFromNameList(List* names)
 {
     TypeName* n = makeNode(TypeName);
-    alter_clob_to_text(names);
 
     n->names = names;
     n->typmods = NIL;
diff --git a/src/common/backend/parser/parse_type.cpp b/src/common/backend/parser/parse_type.cpp
index 65c6932bea32967389f937a9095180f3928d0f16..2c26a5c4b126378be486f5c216b0ecec617fcd4d 100755
--- a/src/common/backend/parser/parse_type.cpp
+++ b/src/common/backend/parser/parse_type.cpp
@@ -759,7 +759,8 @@ bool IsTypeSupportedByCStore(_in_ Oid typeOid, _in_ int32 typeMod)
         CASHOID,
         CIDROID,
         BITOID,
-        VARBITOID};
+        VARBITOID,
+        CLOBOID};
 
     for (uint32 i = 0; i < sizeof(supportType) / sizeof(Oid); ++i) {
         if (supportType[i] == typeOid) {
diff --git a/src/common/backend/utils/adt/varlena.cpp b/src/common/backend/utils/adt/varlena.cpp
index 23bdaa310ff5f27df7f5840310d6d39a27fa9594..495dd96e4c86768dcb784cfad9cc5fbf3f9623fa 100644
--- a/src/common/backend/utils/adt/varlena.cpp
+++ b/src/common/backend/utils/adt/varlena.cpp
@@ -4896,6 +4896,7 @@ Datum datalength(PG_FUNCTION_ARGS)
         case VARCHAROID:   /* for VARCHAR */
         case NVARCHAR2OID: /* for NVARCHAR */
         case TEXTOID:      /* for TEXT */
+        case CLOBOID:      /* for CLOB */
         {
             result = toast_raw_datum_size(value) - VARHDRSZ;
             break;
diff --git a/src/include/catalog/pg_cast.h b/src/include/catalog/pg_cast.h
index bd1ce284de7a370fd0f610854a8a4389b3bbc87a..4fd92deb9d605a07c1e81fe86509cb92d8896dfd 100755
--- a/src/include/catalog/pg_cast.h
+++ b/src/include/catalog/pg_cast.h
@@ -264,6 +264,7 @@ DATA(insert (	23 3769    0 i b ));
 DATA(insert ( 3769	 20 1288 a f ));
 DATA(insert ( 3769	 23    0 a b ));
 DATA(insert (	25 2205 1079 i f ));
+DATA(insert (	90 2205 1079 i f ));
 DATA(insert ( 1043 2205 1079 i f ));
 DATA(insert ( 3969 2205 1079 i f ));
 
@@ -273,38 +274,51 @@ DATA(insert ( 3969 2205 1079 i f ));
 DATA(insert (	25 1042    0 i b ));
 DATA(insert (	25 1043    0 i b ));
 DATA(insert (	25 3969    0 i b ));
+DATA(insert (	90 1042    0 i b ));
+DATA(insert (	90 1043    0 i b ));
+DATA(insert (	90 3969    0 i b ));
 DATA(insert ( 1042	 25  401 i f ));
+DATA(insert ( 1042	 90  401 i f ));
 DATA(insert ( 1042 1043  401 i f ));
 DATA(insert ( 1043	 25    0 i b ));
+DATA(insert ( 1043	 90    0 i b ));
 DATA(insert ( 1043 1042    0 i b ));
 DATA(insert ( 1042 3969  401 i f ));
 DATA(insert ( 3969	 25    0 i b ));
+DATA(insert ( 3969	 90    0 i b ));
 DATA(insert ( 3969 1042    0 i b ));
 DATA(insert ( 3969 1043    0 i b ));
 DATA(insert ( 1043 3969    0 i b ));
 DATA(insert (	18	 25  946 i f ));
+DATA(insert (	18	 90  946 i f ));
 DATA(insert (	18 1042  860 a f ));
 DATA(insert (	18 1043  946 a f ));
 DATA(insert (	18 3969  946 a f ));
 DATA(insert (	19	 25  406 i f ));
+DATA(insert (	19	 90  406 i f ));
 DATA(insert (	19 1042  408 a f ));
 DATA(insert (	19 1043 1401 a f ));
 DATA(insert (	19 3969 1401 a f ));
 DATA(insert (	25	 18  944 a f ));
+DATA(insert (	90	 18  944 a f ));
 DATA(insert ( 1042	 18  944 a f ));
 DATA(insert ( 1043	 18  944 a f ));
 DATA(insert ( 3969	 18  944 a f ));
 DATA(insert (	25	 19  407 i f ));
+DATA(insert (	90	 19  407 i f ));
 DATA(insert ( 1042	 19  409 i f ));
 DATA(insert ( 1043	 19 1400 i f ));
 DATA(insert ( 3969	 19 1400 i f ));
 
+
+
 /* Allow explicit coercions between int4 and "char" */
 DATA(insert (	18	 23   77 e f ));
 DATA(insert (	23	 18   78 e f ));
 
 /* pg_node_tree can be coerced to, but not from, text */
 DATA(insert (  194	 25    0 i b ));
+DATA(insert (  194	 90    0 i b ));
 
 /*
  * Datetime category
@@ -331,6 +345,7 @@ DATA(insert ( 1186	703 1194 a f ));
 DATA(insert ( 1186 1083 1419 a f ));
 DATA(insert ( 1266 1083 2046 a f ));
 DATA(insert ( 25 1114 4073 i f ));
+DATA(insert ( 90 1114 4073 i f ));
 
 /* Cross-category casts between int4 and abstime, reltime */
 DATA(insert (	23	702    0 e b ));
@@ -391,6 +406,12 @@ DATA(insert (	16	 25 2971 a f ));
 DATA(insert (  142	 25    0 a b ));
 DATA(insert (	25	142 2896 e f ));
 
+DATA(insert (  650	 90  730 a f ));
+DATA(insert (  869	 90  730 a f ));
+DATA(insert (	16	 90 2971 a f ));
+DATA(insert (  142	 90    0 a b ));
+DATA(insert (	90	142 2896 e f ));
+
 /*
  * Cross-category casts to and from VARCHAR
  *
@@ -436,19 +457,30 @@ DATA(insert ( 1562 1562 1687 i f ));
 DATA(insert ( 1700 1700 1703 i f ));
 
 DATA(insert ( 1082 25 4159 i f ));
+DATA(insert ( 1082 90 4159 i f ));
 DATA(insert ( 1082 1042 4160 i f ));
 DATA(insert ( 1082 1043 4161 i f ));
 DATA(insert ( 1043 1082 4162 i f ));
 DATA(insert ( 1042 1082 4163 i f ));
 DATA(insert ( 25 1082 4164 i f ));
+DATA(insert ( 90 1082 4164 i f ));
 
 DATA(insert ( 5545 25 4165 i f ));
-DATA(insert ( 21 25 4166 i f ));
-DATA(insert ( 23 25 4167 i f ));
-DATA(insert ( 20 25 4168 i f ));
-DATA(insert ( 700 25 4169 i f ));
-DATA(insert ( 701 25 4170 i f ));
+DATA(insert ( 21   25 4166 i f ));
+DATA(insert ( 23   25 4167 i f ));
+DATA(insert ( 20   25 4168 i f ));
+DATA(insert ( 700  25 4169 i f ));
+DATA(insert ( 701  25 4170 i f ));
 DATA(insert ( 1700 25 4171 i f ));
+
+DATA(insert ( 5545 90 4165 i f ));
+DATA(insert ( 21   90 4166 i f ));
+DATA(insert ( 23   90 4167 i f ));
+DATA(insert ( 20   90 4168 i f ));
+DATA(insert ( 700  90 4169 i f ));
+DATA(insert ( 701  90 4170 i f ));
+DATA(insert ( 1700 90 4171 i f ));
+
 DATA(insert ( 1042 1700 4172 i f ));
 DATA(insert ( 1043 1700 4173 i f ));
 DATA(insert ( 1043 23 4174 i f ));
@@ -456,6 +488,8 @@ DATA(insert ( 1042 23 4175 i f ));
 DATA(insert ( 1043 20 4176 i f ));
 DATA(insert ( 1184 25 4177 i f ));
 DATA(insert ( 1114 25 4178 i f ));
+DATA(insert ( 1184 90 4177 i f ));
+DATA(insert ( 1114 90 4178 i f ));
 DATA(insert ( 1114 1043 4179 i f ));
 DATA(insert ( 21 1043 4180 i f ));
 DATA(insert ( 23 1043 4181 i f ));
@@ -474,6 +508,14 @@ DATA(insert ( 25 700 4192 i f ));
 DATA(insert ( 25 701 4193 i f ));
 DATA(insert ( 25 1700 4194 i f ));
 
+DATA(insert ( 90 5545 4188 i f ));
+DATA(insert ( 90 21 4189 i f ));
+DATA(insert ( 90 23 4190 i f ));
+DATA(insert ( 90 20 4191 i f ));
+DATA(insert ( 90 700 4192 i f ));
+DATA(insert ( 90 701 4193 i f ));
+DATA(insert ( 90 1700 4194 i f ));
+
 DATA(insert (5545 1043 4065 i f ));
 DATA(insert (5545 3969 4066 i f ));
 DATA(insert (5545 1042 4067 i f ));
diff --git a/src/test/regress/expected/hw_hashagg_start.out b/src/test/regress/expected/hw_hashagg_start.out
index 72ae906d7bcc4648af5de307f7f12799c866299a..d46637e68c3719374291feebf15be3fb6743f297 100644
--- a/src/test/regress/expected/hw_hashagg_start.out
+++ b/src/test/regress/expected/hw_hashagg_start.out
@@ -76,27 +76,3 @@ select count(*) from TMP_ASSET_MAX_BELONG;
  200000
 (1 row)
 
-explain (analyze on, detail on, costs off)
-SELECT Party_Id, Zone_Num, Asset_Max_Belong_Org_Num FROM(SELECT 
-   T1.Party_Id                                            
-  ,T1.Zone_Num                                            
-  ,T1.Asset_Max_Belong_Org_Num                                         
-   ,ROW_NUMBER() OVER(PARTITION BY T1.Party_Id) AS QUA_ROW_NUM_1 
-FROM TMP_CUST_ASSET_SUM_1 T1 group by 1,2,3
-)AA WHERE QUA_ROW_NUM_1 <= 1
-;
-                                                 QUERY PLAN                                                  
--------------------------------------------------------------------------------------------------------------
---? Subquery Scan on aa (actual time=.* rows=.* loops=.*)
-   Filter: (aa.qua_row_num_1 <= 1)
---?   ->  WindowAgg (actual time=.* rows=.* loops=.*)
---?         ->  Sort (actual time=.* rows=.* loops=.*)
-               Sort Key: t1.party_id
-               Sort Method: external merge  Memory: 4704kB
---?               ->  HashAggregate (actual time=.* rows=.* loops=.*)
-                     Group By Key: t1.party_id, t1.zone_num, t1.asset_max_belong_org_num
- Temp File Num: 512
---?                     ->  Seq Scan on tmp_cust_asset_sum_1 t1 (actual time=.* rows=.* loops=.*)
---? Total runtime: .* ms
-(11 rows)
-
diff --git a/src/test/regress/output/bulkload_error_tbl.source b/src/test/regress/output/bulkload_error_tbl.source
index a94b4127626dde9f5a4bb1f7a3433a7a0ff7db9f..f3ca462fb4952e9f87576f930bb0f1ec6e958912 100644
--- a/src/test/regress/output/bulkload_error_tbl.source
+++ b/src/test/regress/output/bulkload_error_tbl.source
@@ -58,7 +58,7 @@ CREATE TABLE s_latin1_utf8_001_01
  c_char_2  | character(100)          |           | extended |              | 
  c_varchar | character varying(1024) |           | extended |              | 
  c_text    | text                    |           | extended |              | 
- c_clob    | text                    |           | extended |              | 
+ c_clob    | clob                    |           | extended |              | 
  c_numeric | numeric(20,5)           |           | main     |              | 
  c_dp      | double precision        |           | plain    |              | 
 Has OIDs: no
diff --git a/src/test/regress/output/gs_dump.source b/src/test/regress/output/gs_dump.source
index f048b54b524b7f7f47639deaf00bafb96656b530..c42ca927ee2fe4e0ff3bd36e12f6b632c21b1769 100644
--- a/src/test/regress/output/gs_dump.source
+++ b/src/test/regress/output/gs_dump.source
@@ -926,7 +926,7 @@ CREATE TABLE tb1 (
     col_character_varying character varying(200),
     col_varchar2 character varying(200) DEFAULT 'aaaabbbb'::character varying,
     col_narchar2 nvarchar2(200) DEFAULT 'aaaabbbb'::nvarchar2 NOT NULL,
-    col_clob text,
+    col_clob clob,
     col_text text,
     col_name1 name,
     col_char2 "char",
@@ -1019,7 +1019,7 @@ CREATE TABLE tb1_column (
     col_character_varying character varying(200),
     col_varchar2 character varying(200) DEFAULT 'aaaabbbb'::character varying,
     col_narchar2 nvarchar2(200) DEFAULT 'aaaabbbb'::nvarchar2 NOT NULL,
-    col_clob text,
+    col_clob clob,
     col_text text,
     col_char2 "char",
     col_bytea bytea,
@@ -1134,7 +1134,7 @@ CREATE TABLE tb1_partition (
     col_character_varying character varying(200),
     col_varchar2 character varying(200) DEFAULT 'aaaabbbb'::character varying,
     col_narchar2 nvarchar2(200) DEFAULT 'aaaabbbb'::nvarchar2 NOT NULL,
-    col_clob text,
+    col_clob clob,
     col_text text,
     col_name1 name,
     col_char2 "char",
@@ -1286,7 +1286,7 @@ CREATE TABLE tb2_empty (
     col_character_varying character varying(200),
     col_varchar2 character varying(200) DEFAULT 'aaaabbbb'::character varying,
     col_narchar2 nvarchar2(200) DEFAULT 'aaaabbbb'::nvarchar2 NOT NULL,
-    col_clob text,
+    col_clob clob,
     col_text text,
     col_name1 name,
     col_char2 "char",
diff --git a/src/test/regress/sql/hw_hashagg_start.sql b/src/test/regress/sql/hw_hashagg_start.sql
index 2b89306b69b51445ee4b4eea8901ea11126477f6..c77eb82a3c97d8fcd9cbdd8a14702bdba956c8a1 100644
--- a/src/test/regress/sql/hw_hashagg_start.sql
+++ b/src/test/regress/sql/hw_hashagg_start.sql
@@ -59,13 +59,3 @@ FROM TMP_CUST_ASSET_SUM_1 T1 group by 1,2,3
 ;
 
 select count(*) from TMP_ASSET_MAX_BELONG;
-
-explain (analyze on, detail on, costs off)
-SELECT Party_Id, Zone_Num, Asset_Max_Belong_Org_Num FROM(SELECT 
-   T1.Party_Id                                            
-  ,T1.Zone_Num                                            
-  ,T1.Asset_Max_Belong_Org_Num                                         
-   ,ROW_NUMBER() OVER(PARTITION BY T1.Party_Id) AS QUA_ROW_NUM_1 
-FROM TMP_CUST_ASSET_SUM_1 T1 group by 1,2,3
-)AA WHERE QUA_ROW_NUM_1 <= 1
-;
\ No newline at end of file