diff --git a/src/backend/distributed/commands/table.c b/src/backend/distributed/commands/table.c
index ddb4e5ace..fe256feeb 100644
--- a/src/backend/distributed/commands/table.c
+++ b/src/backend/distributed/commands/table.c
@@ -1060,11 +1060,13 @@ ErrorIfUnsupportedAlterTableStmt(AlterTableStmt *alterTableStatement)
 			case AT_EnableTrigAll:
 			case AT_DisableTrigAll:
 			case AT_ReplicaIdentity:
+			case AT_ValidateConstraint:
 			{
 				/*
 				 * We will not perform any special check for ALTER TABLE DROP CONSTRAINT
 				 * , ALTER TABLE .. ALTER COLUMN .. SET NOT NULL and ALTER TABLE ENABLE/
-				 * DISABLE TRIGGER ALL, ALTER TABLE .. REPLICA IDENTITY ..
+				 * DISABLE TRIGGER ALL, ALTER TABLE .. REPLICA IDENTITY .., ALTER TABLE
+				 * .. VALIDATE CONSTRAINT ..
 				 */
 				break;
 			}
@@ -1083,7 +1085,7 @@ ErrorIfUnsupportedAlterTableStmt(AlterTableStmt *alterTableStatement)
 						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 						 errmsg("alter table command is currently unsupported"),
 						 errdetail("Only ADD|DROP COLUMN, SET|DROP NOT NULL, "
-								   "SET|DROP DEFAULT, ADD|DROP CONSTRAINT, "
+								   "SET|DROP DEFAULT, ADD|DROP|VALIDATE CONSTRAINT, "
 								   "SET (), RESET (), "
 								   "ATTACH|DETACH PARTITION and TYPE subcommands "
 								   "are supported.")));
diff --git a/src/backend/distributed/relay/relay_event_utility.c b/src/backend/distributed/relay/relay_event_utility.c
index 9d5cbd390..2d4dea85b 100644
--- a/src/backend/distributed/relay/relay_event_utility.c
+++ b/src/backend/distributed/relay/relay_event_utility.c
@@ -113,7 +113,11 @@ RelayEventExtendNames(Node *parseTree, char *schemaName, uint64 shardId)
 
 					AppendShardIdToConstraintName(command, shardId);
 				}
-				if (command->subtype == AT_DropConstraint)
+				else if (command->subtype == AT_DropConstraint)
+				{
+					AppendShardIdToConstraintName(command, shardId);
+				}
+				else if (command->subtype == AT_ValidateConstraint)
 				{
 					AppendShardIdToConstraintName(command, shardId);
 				}
@@ -598,7 +602,8 @@ AppendShardIdToConstraintName(AlterTableCmd *command, uint64 shardId)
 		char **constraintName = &(constraint->conname);
 		AppendShardIdToName(constraintName, shardId);
 	}
-	else if (command->subtype == AT_DropConstraint)
+	else if (command->subtype == AT_DropConstraint ||
+			 command->subtype == AT_ValidateConstraint)
 	{
 		char **constraintName = &(command->name);
 		AppendShardIdToName(constraintName, shardId);
diff --git a/src/test/regress/expected/foreign_key_to_reference_table.out b/src/test/regress/expected/foreign_key_to_reference_table.out
index a3e42af88..8b73fa63d 100644
--- a/src/test/regress/expected/foreign_key_to_reference_table.out
+++ b/src/test/regress/expected/foreign_key_to_reference_table.out
@@ -1,6 +1,13 @@
 --
 -- FOREIGN_KEY_TO_REFERENCE_TABLE
 --
+SHOW server_version \gset
+SELECT substring(:'server_version', '\d+')::int > 9 AS version_above_nine;
+ version_above_nine 
+--------------------
+ t
+(1 row)
+
 CREATE SCHEMA fkey_reference_table;
 SET search_path TO 'fkey_reference_table';
 SET citus.shard_replication_factor TO 1;
@@ -28,7 +35,9 @@ SELECT
           relid::regclass::text,
           refd_relid::regclass::text
         FROM
-          table_fkey_cols 
+          table_fkey_cols
+        WHERE
+          "schema" = 'fkey_reference_table'
       )
       d $$ )).RESULT::json )::json )).* ;
 CREATE TABLE referenced_table(id int UNIQUE, test_column int);
@@ -722,38 +731,6 @@ INSERT INTO referencing_table SELECT x,(random()*1000)::int FROM generate_series
 DROP TABLE referenced_table CASCADE;
 NOTICE:  drop cascades to constraint fkey_ref on table referencing_table
 DROP TABLE referencing_table CASCADE;
--- In the following test, we show that Citus currently does not support 
--- VALIDATE command.
-CREATE TABLE referenced_table(test_column int, test_column2 int, PRIMARY KEY(test_column));
-CREATE TABLE referencing_table(id int, ref_id int DEFAULT -1);
-SELECT create_reference_table('referenced_table');
- create_reference_table 
-------------------------
- 
-(1 row)
-
-SELECT create_distributed_table('referencing_table', 'id');
- create_distributed_table 
---------------------------
- 
-(1 row)
-
-ALTER TABLE referencing_table ADD CONSTRAINT fkey_ref FOREIGN KEY (ref_id) REFERENCES referenced_table(test_column) ON DELETE SET DEFAULT NOT VALID;
--- Even if the foreign constraint is added with "NOT VALID",
--- we make sure that it is still applied to the upcoming inserts.
-INSERT INTO referenced_table SELECT x, x FROM generate_series(0,1000) AS f(x);
-INSERT INTO referencing_table SELECT x, x FROM generate_series(0,1000) AS f(x);
--- we expect this to fail because of the foreign constraint.
-INSERT INTO referencing_table SELECT x, x FROM generate_series(1000,1001) AS f(x);
-ERROR:  insert or update on table "referencing_table_7000220" violates foreign key constraint "fkey_ref_7000220"
-DETAIL:  Key (ref_id)=(1001) is not present in table "referenced_table_7000214".
--- currently not supported
-ALTER TABLE referencing_table VALIDATE CONSTRAINT fkey_ref;
-ERROR:  alter table command is currently unsupported
-DETAIL:  Only ADD|DROP COLUMN, SET|DROP NOT NULL, SET|DROP DEFAULT, ADD|DROP CONSTRAINT, SET (), RESET (), ATTACH|DETACH PARTITION and TYPE subcommands are supported.
-DROP TABLE referenced_table CASCADE;
-NOTICE:  drop cascades to constraint fkey_ref on table referencing_table
-DROP TABLE referencing_table CASCADE;
 -- In the following tests, we create a foreign constraint with 
 -- ON UPDATE CASCADE and see if it works properly with cascading upsert
 CREATE TABLE referenced_table(test_column int, test_column2 int, PRIMARY KEY(test_column));
@@ -845,38 +822,38 @@ ALTER TABLE referencing_table ADD CONSTRAINT foreign_key_2 FOREIGN KEY (id) REFE
 SELECT * FROM table_fkeys_in_workers WHERE relid LIKE 'fkey_reference_table.%' AND refd_relid LIKE 'fkey_reference_table.%' ORDER BY 1,2,3;
          name          |                     relid                      |                   refd_relid                   
 -----------------------+------------------------------------------------+------------------------------------------------
- fkey_ref_7000235      | fkey_reference_table.referencing_table_7000235 | fkey_reference_table.referenced_table_7000233
- fkey_ref_7000236      | fkey_reference_table.referencing_table_7000236 | fkey_reference_table.referenced_table_7000233
- fkey_ref_7000237      | fkey_reference_table.referencing_table_7000237 | fkey_reference_table.referenced_table_7000233
- fkey_ref_7000238      | fkey_reference_table.referencing_table_7000238 | fkey_reference_table.referenced_table_7000233
- fkey_ref_7000239      | fkey_reference_table.referencing_table_7000239 | fkey_reference_table.referenced_table_7000233
- fkey_ref_7000240      | fkey_reference_table.referencing_table_7000240 | fkey_reference_table.referenced_table_7000233
- fkey_ref_7000241      | fkey_reference_table.referencing_table_7000241 | fkey_reference_table.referenced_table_7000233
- fkey_ref_7000242      | fkey_reference_table.referencing_table_7000242 | fkey_reference_table.referenced_table_7000233
- foreign_key_2_7000235 | fkey_reference_table.referencing_table_7000235 | fkey_reference_table.referenced_table2_7000234
- foreign_key_2_7000236 | fkey_reference_table.referencing_table_7000236 | fkey_reference_table.referenced_table2_7000234
- foreign_key_2_7000237 | fkey_reference_table.referencing_table_7000237 | fkey_reference_table.referenced_table2_7000234
- foreign_key_2_7000238 | fkey_reference_table.referencing_table_7000238 | fkey_reference_table.referenced_table2_7000234
- foreign_key_2_7000239 | fkey_reference_table.referencing_table_7000239 | fkey_reference_table.referenced_table2_7000234
- foreign_key_2_7000240 | fkey_reference_table.referencing_table_7000240 | fkey_reference_table.referenced_table2_7000234
- foreign_key_2_7000241 | fkey_reference_table.referencing_table_7000241 | fkey_reference_table.referenced_table2_7000234
- foreign_key_2_7000242 | fkey_reference_table.referencing_table_7000242 | fkey_reference_table.referenced_table2_7000234
+ fkey_ref_7000226      | fkey_reference_table.referencing_table_7000226 | fkey_reference_table.referenced_table_7000224
+ fkey_ref_7000227      | fkey_reference_table.referencing_table_7000227 | fkey_reference_table.referenced_table_7000224
+ fkey_ref_7000228      | fkey_reference_table.referencing_table_7000228 | fkey_reference_table.referenced_table_7000224
+ fkey_ref_7000229      | fkey_reference_table.referencing_table_7000229 | fkey_reference_table.referenced_table_7000224
+ fkey_ref_7000230      | fkey_reference_table.referencing_table_7000230 | fkey_reference_table.referenced_table_7000224
+ fkey_ref_7000231      | fkey_reference_table.referencing_table_7000231 | fkey_reference_table.referenced_table_7000224
+ fkey_ref_7000232      | fkey_reference_table.referencing_table_7000232 | fkey_reference_table.referenced_table_7000224
+ fkey_ref_7000233      | fkey_reference_table.referencing_table_7000233 | fkey_reference_table.referenced_table_7000224
+ foreign_key_2_7000226 | fkey_reference_table.referencing_table_7000226 | fkey_reference_table.referenced_table2_7000225
+ foreign_key_2_7000227 | fkey_reference_table.referencing_table_7000227 | fkey_reference_table.referenced_table2_7000225
+ foreign_key_2_7000228 | fkey_reference_table.referencing_table_7000228 | fkey_reference_table.referenced_table2_7000225
+ foreign_key_2_7000229 | fkey_reference_table.referencing_table_7000229 | fkey_reference_table.referenced_table2_7000225
+ foreign_key_2_7000230 | fkey_reference_table.referencing_table_7000230 | fkey_reference_table.referenced_table2_7000225
+ foreign_key_2_7000231 | fkey_reference_table.referencing_table_7000231 | fkey_reference_table.referenced_table2_7000225
+ foreign_key_2_7000232 | fkey_reference_table.referencing_table_7000232 | fkey_reference_table.referenced_table2_7000225
+ foreign_key_2_7000233 | fkey_reference_table.referencing_table_7000233 | fkey_reference_table.referenced_table2_7000225
 (16 rows)
 
 INSERT INTO referenced_table SELECT x, x+1 FROM generate_series(0,1000) AS f(x);
 INSERT INTO referenced_table2 SELECT x, x+1 FROM generate_series(500,1500) AS f(x);
 -- should fail
 INSERT INTO referencing_table SELECT x, x+1 FROM generate_series(0,1500) AS f(x);
-ERROR:  insert or update on table "referencing_table_7000242" violates foreign key constraint "foreign_key_2_7000242"
-DETAIL:  Key (id)=(9) is not present in table "referenced_table2_7000234".
+ERROR:  insert or update on table "referencing_table_7000227" violates foreign key constraint "foreign_key_2_7000227"
+DETAIL:  Key (id)=(5) is not present in table "referenced_table2_7000225".
 -- should fail
 INSERT INTO referencing_table SELECT x, x+1 FROM generate_series(0,400) AS f(x);
-ERROR:  insert or update on table "referencing_table_7000242" violates foreign key constraint "foreign_key_2_7000242"
-DETAIL:  Key (id)=(9) is not present in table "referenced_table2_7000234".
+ERROR:  insert or update on table "referencing_table_7000227" violates foreign key constraint "foreign_key_2_7000227"
+DETAIL:  Key (id)=(5) is not present in table "referenced_table2_7000225".
 -- should fail
 INSERT INTO referencing_table SELECT x, x+1 FROM generate_series(1000,1400) AS f(x);
-ERROR:  insert or update on table "referencing_table_7000242" violates foreign key constraint "fkey_ref_7000242"
-DETAIL:  Key (id)=(1023) is not present in table "referenced_table_7000233".
+ERROR:  insert or update on table "referencing_table_7000227" violates foreign key constraint "fkey_ref_7000227"
+DETAIL:  Key (id)=(1005) is not present in table "referenced_table_7000224".
 -- should success
 INSERT INTO referencing_table SELECT x, x+1 FROM generate_series(600,900) AS f(x);
 SELECT count(*) FROM referencing_table;
@@ -972,38 +949,38 @@ COMMIT;
 SELECT * FROM table_fkeys_in_workers WHERE relid LIKE 'fkey_reference_table.%' AND refd_relid LIKE 'fkey_reference_table.%' ORDER BY 1,2,3;
          name          |                     relid                      |                   refd_relid                   
 -----------------------+------------------------------------------------+------------------------------------------------
- fkey_ref_7000255      | fkey_reference_table.referencing_table_7000255 | fkey_reference_table.referenced_table_7000253
- fkey_ref_7000256      | fkey_reference_table.referencing_table_7000256 | fkey_reference_table.referenced_table_7000253
- fkey_ref_7000257      | fkey_reference_table.referencing_table_7000257 | fkey_reference_table.referenced_table_7000253
- fkey_ref_7000258      | fkey_reference_table.referencing_table_7000258 | fkey_reference_table.referenced_table_7000253
- fkey_ref_7000259      | fkey_reference_table.referencing_table_7000259 | fkey_reference_table.referenced_table_7000253
- fkey_ref_7000260      | fkey_reference_table.referencing_table_7000260 | fkey_reference_table.referenced_table_7000253
- fkey_ref_7000261      | fkey_reference_table.referencing_table_7000261 | fkey_reference_table.referenced_table_7000253
- fkey_ref_7000262      | fkey_reference_table.referencing_table_7000262 | fkey_reference_table.referenced_table_7000253
- foreign_key_2_7000255 | fkey_reference_table.referencing_table_7000255 | fkey_reference_table.referenced_table2_7000254
- foreign_key_2_7000256 | fkey_reference_table.referencing_table_7000256 | fkey_reference_table.referenced_table2_7000254
- foreign_key_2_7000257 | fkey_reference_table.referencing_table_7000257 | fkey_reference_table.referenced_table2_7000254
- foreign_key_2_7000258 | fkey_reference_table.referencing_table_7000258 | fkey_reference_table.referenced_table2_7000254
- foreign_key_2_7000259 | fkey_reference_table.referencing_table_7000259 | fkey_reference_table.referenced_table2_7000254
- foreign_key_2_7000260 | fkey_reference_table.referencing_table_7000260 | fkey_reference_table.referenced_table2_7000254
- foreign_key_2_7000261 | fkey_reference_table.referencing_table_7000261 | fkey_reference_table.referenced_table2_7000254
- foreign_key_2_7000262 | fkey_reference_table.referencing_table_7000262 | fkey_reference_table.referenced_table2_7000254
+ fkey_ref_7000246      | fkey_reference_table.referencing_table_7000246 | fkey_reference_table.referenced_table_7000244
+ fkey_ref_7000247      | fkey_reference_table.referencing_table_7000247 | fkey_reference_table.referenced_table_7000244
+ fkey_ref_7000248      | fkey_reference_table.referencing_table_7000248 | fkey_reference_table.referenced_table_7000244
+ fkey_ref_7000249      | fkey_reference_table.referencing_table_7000249 | fkey_reference_table.referenced_table_7000244
+ fkey_ref_7000250      | fkey_reference_table.referencing_table_7000250 | fkey_reference_table.referenced_table_7000244
+ fkey_ref_7000251      | fkey_reference_table.referencing_table_7000251 | fkey_reference_table.referenced_table_7000244
+ fkey_ref_7000252      | fkey_reference_table.referencing_table_7000252 | fkey_reference_table.referenced_table_7000244
+ fkey_ref_7000253      | fkey_reference_table.referencing_table_7000253 | fkey_reference_table.referenced_table_7000244
+ foreign_key_2_7000246 | fkey_reference_table.referencing_table_7000246 | fkey_reference_table.referenced_table2_7000245
+ foreign_key_2_7000247 | fkey_reference_table.referencing_table_7000247 | fkey_reference_table.referenced_table2_7000245
+ foreign_key_2_7000248 | fkey_reference_table.referencing_table_7000248 | fkey_reference_table.referenced_table2_7000245
+ foreign_key_2_7000249 | fkey_reference_table.referencing_table_7000249 | fkey_reference_table.referenced_table2_7000245
+ foreign_key_2_7000250 | fkey_reference_table.referencing_table_7000250 | fkey_reference_table.referenced_table2_7000245
+ foreign_key_2_7000251 | fkey_reference_table.referencing_table_7000251 | fkey_reference_table.referenced_table2_7000245
+ foreign_key_2_7000252 | fkey_reference_table.referencing_table_7000252 | fkey_reference_table.referenced_table2_7000245
+ foreign_key_2_7000253 | fkey_reference_table.referencing_table_7000253 | fkey_reference_table.referenced_table2_7000245
 (16 rows)
 
 INSERT INTO referenced_table SELECT x, x+1 FROM generate_series(0,1000) AS f(x);
 INSERT INTO referenced_table2 SELECT x, x+1 FROM generate_series(500,1500) AS f(x);
 -- should fail
 INSERT INTO referencing_table SELECT x, x+1 FROM generate_series(0,1500) AS f(x);
-ERROR:  insert or update on table "referencing_table_7000260" violates foreign key constraint "foreign_key_2_7000260"
-DETAIL:  Key (ref_id)=(7) is not present in table "referenced_table2_7000254".
+ERROR:  insert or update on table "referencing_table_7000251" violates foreign key constraint "foreign_key_2_7000251"
+DETAIL:  Key (ref_id)=(7) is not present in table "referenced_table2_7000245".
 -- should fail
 INSERT INTO referencing_table SELECT x, x+1 FROM generate_series(0,400) AS f(x);
-ERROR:  insert or update on table "referencing_table_7000260" violates foreign key constraint "foreign_key_2_7000260"
-DETAIL:  Key (ref_id)=(7) is not present in table "referenced_table2_7000254".
+ERROR:  insert or update on table "referencing_table_7000251" violates foreign key constraint "foreign_key_2_7000251"
+DETAIL:  Key (ref_id)=(7) is not present in table "referenced_table2_7000245".
 -- should fail
 INSERT INTO referencing_table SELECT x, x+1 FROM generate_series(1000,1400) AS f(x);
-ERROR:  insert or update on table "referencing_table_7000260" violates foreign key constraint "fkey_ref_7000260"
-DETAIL:  Key (id)=(1001) is not present in table "referenced_table_7000253".
+ERROR:  insert or update on table "referencing_table_7000251" violates foreign key constraint "fkey_ref_7000251"
+DETAIL:  Key (id)=(1001) is not present in table "referenced_table_7000244".
 -- should success
 INSERT INTO referencing_table SELECT x, x+501 FROM generate_series(0,1000) AS f(x);
 SELECT count(*) FROM referencing_table;
@@ -1105,43 +1082,43 @@ COMMIT;
 SELECT * FROM table_fkeys_in_workers WHERE relid LIKE 'fkey_reference_table.%' AND refd_relid LIKE 'fkey_reference_table.%' ORDER BY 1,2,3;
            name           |                      relid                      |                   refd_relid                   
 --------------------------+-------------------------------------------------+------------------------------------------------
- fkey_ref_7000274         | fkey_reference_table.referencing_table_7000274  | fkey_reference_table.referenced_table_7000273
- fkey_ref_7000275         | fkey_reference_table.referencing_table_7000275  | fkey_reference_table.referenced_table_7000273
- fkey_ref_7000276         | fkey_reference_table.referencing_table_7000276  | fkey_reference_table.referenced_table_7000273
- fkey_ref_7000277         | fkey_reference_table.referencing_table_7000277  | fkey_reference_table.referenced_table_7000273
- fkey_ref_7000278         | fkey_reference_table.referencing_table_7000278  | fkey_reference_table.referenced_table_7000273
- fkey_ref_7000279         | fkey_reference_table.referencing_table_7000279  | fkey_reference_table.referenced_table_7000273
- fkey_ref_7000280         | fkey_reference_table.referencing_table_7000280  | fkey_reference_table.referenced_table_7000273
- fkey_ref_7000281         | fkey_reference_table.referencing_table_7000281  | fkey_reference_table.referenced_table_7000273
- fkey_ref_7000282         | fkey_reference_table.referencing_table2_7000282 | fkey_reference_table.referenced_table_7000273
- fkey_ref_7000283         | fkey_reference_table.referencing_table2_7000283 | fkey_reference_table.referenced_table_7000273
- fkey_ref_7000284         | fkey_reference_table.referencing_table2_7000284 | fkey_reference_table.referenced_table_7000273
- fkey_ref_7000285         | fkey_reference_table.referencing_table2_7000285 | fkey_reference_table.referenced_table_7000273
- fkey_ref_7000286         | fkey_reference_table.referencing_table2_7000286 | fkey_reference_table.referenced_table_7000273
- fkey_ref_7000287         | fkey_reference_table.referencing_table2_7000287 | fkey_reference_table.referenced_table_7000273
- fkey_ref_7000288         | fkey_reference_table.referencing_table2_7000288 | fkey_reference_table.referenced_table_7000273
- fkey_ref_7000289         | fkey_reference_table.referencing_table2_7000289 | fkey_reference_table.referenced_table_7000273
- fkey_ref_to_dist_7000282 | fkey_reference_table.referencing_table2_7000282 | fkey_reference_table.referencing_table_7000274
- fkey_ref_to_dist_7000283 | fkey_reference_table.referencing_table2_7000283 | fkey_reference_table.referencing_table_7000275
- fkey_ref_to_dist_7000284 | fkey_reference_table.referencing_table2_7000284 | fkey_reference_table.referencing_table_7000276
- fkey_ref_to_dist_7000285 | fkey_reference_table.referencing_table2_7000285 | fkey_reference_table.referencing_table_7000277
- fkey_ref_to_dist_7000286 | fkey_reference_table.referencing_table2_7000286 | fkey_reference_table.referencing_table_7000278
- fkey_ref_to_dist_7000287 | fkey_reference_table.referencing_table2_7000287 | fkey_reference_table.referencing_table_7000279
- fkey_ref_to_dist_7000288 | fkey_reference_table.referencing_table2_7000288 | fkey_reference_table.referencing_table_7000280
- fkey_ref_to_dist_7000289 | fkey_reference_table.referencing_table2_7000289 | fkey_reference_table.referencing_table_7000281
+ fkey_ref_7000265         | fkey_reference_table.referencing_table_7000265  | fkey_reference_table.referenced_table_7000264
+ fkey_ref_7000266         | fkey_reference_table.referencing_table_7000266  | fkey_reference_table.referenced_table_7000264
+ fkey_ref_7000267         | fkey_reference_table.referencing_table_7000267  | fkey_reference_table.referenced_table_7000264
+ fkey_ref_7000268         | fkey_reference_table.referencing_table_7000268  | fkey_reference_table.referenced_table_7000264
+ fkey_ref_7000269         | fkey_reference_table.referencing_table_7000269  | fkey_reference_table.referenced_table_7000264
+ fkey_ref_7000270         | fkey_reference_table.referencing_table_7000270  | fkey_reference_table.referenced_table_7000264
+ fkey_ref_7000271         | fkey_reference_table.referencing_table_7000271  | fkey_reference_table.referenced_table_7000264
+ fkey_ref_7000272         | fkey_reference_table.referencing_table_7000272  | fkey_reference_table.referenced_table_7000264
+ fkey_ref_7000273         | fkey_reference_table.referencing_table2_7000273 | fkey_reference_table.referenced_table_7000264
+ fkey_ref_7000274         | fkey_reference_table.referencing_table2_7000274 | fkey_reference_table.referenced_table_7000264
+ fkey_ref_7000275         | fkey_reference_table.referencing_table2_7000275 | fkey_reference_table.referenced_table_7000264
+ fkey_ref_7000276         | fkey_reference_table.referencing_table2_7000276 | fkey_reference_table.referenced_table_7000264
+ fkey_ref_7000277         | fkey_reference_table.referencing_table2_7000277 | fkey_reference_table.referenced_table_7000264
+ fkey_ref_7000278         | fkey_reference_table.referencing_table2_7000278 | fkey_reference_table.referenced_table_7000264
+ fkey_ref_7000279         | fkey_reference_table.referencing_table2_7000279 | fkey_reference_table.referenced_table_7000264
+ fkey_ref_7000280         | fkey_reference_table.referencing_table2_7000280 | fkey_reference_table.referenced_table_7000264
+ fkey_ref_to_dist_7000273 | fkey_reference_table.referencing_table2_7000273 | fkey_reference_table.referencing_table_7000265
+ fkey_ref_to_dist_7000274 | fkey_reference_table.referencing_table2_7000274 | fkey_reference_table.referencing_table_7000266
+ fkey_ref_to_dist_7000275 | fkey_reference_table.referencing_table2_7000275 | fkey_reference_table.referencing_table_7000267
+ fkey_ref_to_dist_7000276 | fkey_reference_table.referencing_table2_7000276 | fkey_reference_table.referencing_table_7000268
+ fkey_ref_to_dist_7000277 | fkey_reference_table.referencing_table2_7000277 | fkey_reference_table.referencing_table_7000269
+ fkey_ref_to_dist_7000278 | fkey_reference_table.referencing_table2_7000278 | fkey_reference_table.referencing_table_7000270
+ fkey_ref_to_dist_7000279 | fkey_reference_table.referencing_table2_7000279 | fkey_reference_table.referencing_table_7000271
+ fkey_ref_to_dist_7000280 | fkey_reference_table.referencing_table2_7000280 | fkey_reference_table.referencing_table_7000272
 (24 rows)
 
 INSERT INTO referenced_table SELECT x, x+1 FROM generate_series(0,1000) AS f(x);
 -- should fail
 INSERT INTO referencing_table2 SELECT x, x+1 FROM generate_series(0,100) AS f(x);
-ERROR:  insert or update on table "referencing_table2_7000284" violates foreign key constraint "fkey_ref_to_dist_7000284"
-DETAIL:  Key (id)=(4) is not present in table "referencing_table_7000276".
+ERROR:  insert or update on table "referencing_table2_7000274" violates foreign key constraint "fkey_ref_to_dist_7000274"
+DETAIL:  Key (id)=(5) is not present in table "referencing_table_7000266".
 -- should success
 INSERT INTO referencing_table SELECT x, x+1 FROM generate_series(0,400) AS f(x);
 -- should fail
 INSERT INTO referencing_table2 SELECT x, x+1 FROM generate_series(200,500) AS f(x);
-ERROR:  insert or update on table "referencing_table2_7000284" violates foreign key constraint "fkey_ref_to_dist_7000284"
-DETAIL:  Key (id)=(408) is not present in table "referencing_table_7000276".
+ERROR:  insert or update on table "referencing_table2_7000274" violates foreign key constraint "fkey_ref_to_dist_7000274"
+DETAIL:  Key (id)=(403) is not present in table "referencing_table_7000266".
 -- should success
 INSERT INTO referencing_table2 SELECT x, x+1 FROM generate_series(0,300) AS f(x);
 DELETE FROM referenced_table WHERE test_column < 200;
@@ -1239,22 +1216,22 @@ ALTER TABLE referencing_table ADD CONSTRAINT fkey_ref FOREIGN KEY (ref_id, ref_i
 SELECT * FROM table_fkeys_in_workers WHERE relid LIKE 'fkey_reference_table.referencing%' ORDER BY 1,2,3;
                      name                      |                           relid                            |                   refd_relid                   
 -----------------------------------------------+------------------------------------------------------------+------------------------------------------------
- fkey_ref_7000308                              | fkey_reference_table.referencing_table_7000308             | fkey_reference_table.referenced_table_7000307
- fkey_ref_7000309                              | fkey_reference_table.referencing_table_7000309             | fkey_reference_table.referenced_table_7000307
- fkey_ref_7000310                              | fkey_reference_table.referencing_table_7000310             | fkey_reference_table.referenced_table_7000307
- fkey_ref_7000311                              | fkey_reference_table.referencing_table_7000311             | fkey_reference_table.referenced_table_7000307
- fkey_ref_7000312                              | fkey_reference_table.referencing_table_7000312             | fkey_reference_table.referenced_table_7000307
- fkey_ref_7000313                              | fkey_reference_table.referencing_table_7000313             | fkey_reference_table.referenced_table_7000307
- fkey_ref_7000314                              | fkey_reference_table.referencing_table_7000314             | fkey_reference_table.referenced_table_7000307
- fkey_ref_7000315                              | fkey_reference_table.referencing_table_7000315             | fkey_reference_table.referenced_table_7000307
- referencing_referencing_table_id_fkey_7000316 | fkey_reference_table.referencing_referencing_table_7000316 | fkey_reference_table.referencing_table_7000308
- referencing_referencing_table_id_fkey_7000317 | fkey_reference_table.referencing_referencing_table_7000317 | fkey_reference_table.referencing_table_7000309
- referencing_referencing_table_id_fkey_7000318 | fkey_reference_table.referencing_referencing_table_7000318 | fkey_reference_table.referencing_table_7000310
- referencing_referencing_table_id_fkey_7000319 | fkey_reference_table.referencing_referencing_table_7000319 | fkey_reference_table.referencing_table_7000311
- referencing_referencing_table_id_fkey_7000320 | fkey_reference_table.referencing_referencing_table_7000320 | fkey_reference_table.referencing_table_7000312
- referencing_referencing_table_id_fkey_7000321 | fkey_reference_table.referencing_referencing_table_7000321 | fkey_reference_table.referencing_table_7000313
- referencing_referencing_table_id_fkey_7000322 | fkey_reference_table.referencing_referencing_table_7000322 | fkey_reference_table.referencing_table_7000314
- referencing_referencing_table_id_fkey_7000323 | fkey_reference_table.referencing_referencing_table_7000323 | fkey_reference_table.referencing_table_7000315
+ fkey_ref_7000299                              | fkey_reference_table.referencing_table_7000299             | fkey_reference_table.referenced_table_7000298
+ fkey_ref_7000300                              | fkey_reference_table.referencing_table_7000300             | fkey_reference_table.referenced_table_7000298
+ fkey_ref_7000301                              | fkey_reference_table.referencing_table_7000301             | fkey_reference_table.referenced_table_7000298
+ fkey_ref_7000302                              | fkey_reference_table.referencing_table_7000302             | fkey_reference_table.referenced_table_7000298
+ fkey_ref_7000303                              | fkey_reference_table.referencing_table_7000303             | fkey_reference_table.referenced_table_7000298
+ fkey_ref_7000304                              | fkey_reference_table.referencing_table_7000304             | fkey_reference_table.referenced_table_7000298
+ fkey_ref_7000305                              | fkey_reference_table.referencing_table_7000305             | fkey_reference_table.referenced_table_7000298
+ fkey_ref_7000306                              | fkey_reference_table.referencing_table_7000306             | fkey_reference_table.referenced_table_7000298
+ referencing_referencing_table_id_fkey_7000307 | fkey_reference_table.referencing_referencing_table_7000307 | fkey_reference_table.referencing_table_7000299
+ referencing_referencing_table_id_fkey_7000308 | fkey_reference_table.referencing_referencing_table_7000308 | fkey_reference_table.referencing_table_7000300
+ referencing_referencing_table_id_fkey_7000309 | fkey_reference_table.referencing_referencing_table_7000309 | fkey_reference_table.referencing_table_7000301
+ referencing_referencing_table_id_fkey_7000310 | fkey_reference_table.referencing_referencing_table_7000310 | fkey_reference_table.referencing_table_7000302
+ referencing_referencing_table_id_fkey_7000311 | fkey_reference_table.referencing_referencing_table_7000311 | fkey_reference_table.referencing_table_7000303
+ referencing_referencing_table_id_fkey_7000312 | fkey_reference_table.referencing_referencing_table_7000312 | fkey_reference_table.referencing_table_7000304
+ referencing_referencing_table_id_fkey_7000313 | fkey_reference_table.referencing_referencing_table_7000313 | fkey_reference_table.referencing_table_7000305
+ referencing_referencing_table_id_fkey_7000314 | fkey_reference_table.referencing_referencing_table_7000314 | fkey_reference_table.referencing_table_7000306
 (16 rows)
 
 INSERT INTO referenced_table SELECT x, x+1 FROM generate_series(1,1000) AS f(x);
@@ -1866,8 +1843,8 @@ ALTER TABLE referencing_table_4 ADD CONSTRAINT fkey FOREIGN KEY (id) REFERENCES
 ALTER TABLE referencing_table_4 ADD CONSTRAINT fkey_to_ref FOREIGN KEY (value_1) REFERENCES referenced_table;
 -- should fail since the data will flow to partitioning_test_4 and it has a foreign constraint to partitioning_test_0 on id column
 INSERT INTO referencing_table VALUES (0, 5);
-ERROR:  insert or update on table "referencing_table_4_7000549" violates foreign key constraint "fkey_7000549"
-DETAIL:  Key (id)=(0) is not present in table "referencing_table_0_7000533".
+ERROR:  insert or update on table "referencing_table_4_7000540" violates foreign key constraint "fkey_7000540"
+DETAIL:  Key (id)=(0) is not present in table "referencing_table_0_7000524".
 CONTEXT:  while executing command on localhost:57638
 -- should succeed on partitioning_test_0
 INSERT INTO referencing_table VALUES (0, 1);
@@ -1879,8 +1856,8 @@ SELECT * FROM referencing_table;
 
 -- should fail since partitioning_test_4 has foreign constraint to referenced_table on value_1 column
 INSERT INTO referencing_table VALUES (0, 5);
-ERROR:  insert or update on table "referencing_table_4_7000549" violates foreign key constraint "fkey_to_ref_7000549"
-DETAIL:  Key (value_1)=(5) is not present in table "referenced_table_7000521".
+ERROR:  insert or update on table "referencing_table_4_7000540" violates foreign key constraint "fkey_to_ref_7000540"
+DETAIL:  Key (value_1)=(5) is not present in table "referenced_table_7000512".
 CONTEXT:  while executing command on localhost:57638
 INSERT INTO referenced_table VALUES(5,5);
 -- should succeed since both of the foreign constraints are positive
diff --git a/src/test/regress/expected/foreign_key_to_reference_table_0.out b/src/test/regress/expected/foreign_key_to_reference_table_0.out
index 7e639e391..a5e6e4e66 100644
--- a/src/test/regress/expected/foreign_key_to_reference_table_0.out
+++ b/src/test/regress/expected/foreign_key_to_reference_table_0.out
@@ -1,6 +1,13 @@
 --
 -- FOREIGN_KEY_TO_REFERENCE_TABLE
 --
+SHOW server_version \gset
+SELECT substring(:'server_version', '\d+')::int > 9 AS version_above_nine;
+ version_above_nine 
+--------------------
+ f
+(1 row)
+
 CREATE SCHEMA fkey_reference_table;
 SET search_path TO 'fkey_reference_table';
 SET citus.shard_replication_factor TO 1;
@@ -28,7 +35,9 @@ SELECT
           relid::regclass::text,
           refd_relid::regclass::text
         FROM
-          table_fkey_cols 
+          table_fkey_cols
+        WHERE
+          "schema" = 'fkey_reference_table'
       )
       d $$ )).RESULT::json )::json )).* ;
 CREATE TABLE referenced_table(id int UNIQUE, test_column int);
@@ -722,38 +731,6 @@ INSERT INTO referencing_table SELECT x,(random()*1000)::int FROM generate_series
 DROP TABLE referenced_table CASCADE;
 NOTICE:  drop cascades to constraint fkey_ref on table referencing_table
 DROP TABLE referencing_table CASCADE;
--- In the following test, we show that Citus currently does not support 
--- VALIDATE command.
-CREATE TABLE referenced_table(test_column int, test_column2 int, PRIMARY KEY(test_column));
-CREATE TABLE referencing_table(id int, ref_id int DEFAULT -1);
-SELECT create_reference_table('referenced_table');
- create_reference_table 
-------------------------
- 
-(1 row)
-
-SELECT create_distributed_table('referencing_table', 'id');
- create_distributed_table 
---------------------------
- 
-(1 row)
-
-ALTER TABLE referencing_table ADD CONSTRAINT fkey_ref FOREIGN KEY (ref_id) REFERENCES referenced_table(test_column) ON DELETE SET DEFAULT NOT VALID;
--- Even if the foreign constraint is added with "NOT VALID",
--- we make sure that it is still applied to the upcoming inserts.
-INSERT INTO referenced_table SELECT x, x FROM generate_series(0,1000) AS f(x);
-INSERT INTO referencing_table SELECT x, x FROM generate_series(0,1000) AS f(x);
--- we expect this to fail because of the foreign constraint.
-INSERT INTO referencing_table SELECT x, x FROM generate_series(1000,1001) AS f(x);
-ERROR:  insert or update on table "referencing_table_7000220" violates foreign key constraint "fkey_ref_7000220"
-DETAIL:  Key (ref_id)=(1001) is not present in table "referenced_table_7000214".
--- currently not supported
-ALTER TABLE referencing_table VALIDATE CONSTRAINT fkey_ref;
-ERROR:  alter table command is currently unsupported
-DETAIL:  Only ADD|DROP COLUMN, SET|DROP NOT NULL, SET|DROP DEFAULT, ADD|DROP CONSTRAINT, SET (), RESET (), ATTACH|DETACH PARTITION and TYPE subcommands are supported.
-DROP TABLE referenced_table CASCADE;
-NOTICE:  drop cascades to constraint fkey_ref on table referencing_table
-DROP TABLE referencing_table CASCADE;
 -- In the following tests, we create a foreign constraint with 
 -- ON UPDATE CASCADE and see if it works properly with cascading upsert
 CREATE TABLE referenced_table(test_column int, test_column2 int, PRIMARY KEY(test_column));
@@ -845,38 +822,38 @@ ALTER TABLE referencing_table ADD CONSTRAINT foreign_key_2 FOREIGN KEY (id) REFE
 SELECT * FROM table_fkeys_in_workers WHERE relid LIKE 'fkey_reference_table.%' AND refd_relid LIKE 'fkey_reference_table.%' ORDER BY 1,2,3;
          name          |                     relid                      |                   refd_relid                   
 -----------------------+------------------------------------------------+------------------------------------------------
- fkey_ref_7000235      | fkey_reference_table.referencing_table_7000235 | fkey_reference_table.referenced_table_7000233
- fkey_ref_7000236      | fkey_reference_table.referencing_table_7000236 | fkey_reference_table.referenced_table_7000233
- fkey_ref_7000237      | fkey_reference_table.referencing_table_7000237 | fkey_reference_table.referenced_table_7000233
- fkey_ref_7000238      | fkey_reference_table.referencing_table_7000238 | fkey_reference_table.referenced_table_7000233
- fkey_ref_7000239      | fkey_reference_table.referencing_table_7000239 | fkey_reference_table.referenced_table_7000233
- fkey_ref_7000240      | fkey_reference_table.referencing_table_7000240 | fkey_reference_table.referenced_table_7000233
- fkey_ref_7000241      | fkey_reference_table.referencing_table_7000241 | fkey_reference_table.referenced_table_7000233
- fkey_ref_7000242      | fkey_reference_table.referencing_table_7000242 | fkey_reference_table.referenced_table_7000233
- foreign_key_2_7000235 | fkey_reference_table.referencing_table_7000235 | fkey_reference_table.referenced_table2_7000234
- foreign_key_2_7000236 | fkey_reference_table.referencing_table_7000236 | fkey_reference_table.referenced_table2_7000234
- foreign_key_2_7000237 | fkey_reference_table.referencing_table_7000237 | fkey_reference_table.referenced_table2_7000234
- foreign_key_2_7000238 | fkey_reference_table.referencing_table_7000238 | fkey_reference_table.referenced_table2_7000234
- foreign_key_2_7000239 | fkey_reference_table.referencing_table_7000239 | fkey_reference_table.referenced_table2_7000234
- foreign_key_2_7000240 | fkey_reference_table.referencing_table_7000240 | fkey_reference_table.referenced_table2_7000234
- foreign_key_2_7000241 | fkey_reference_table.referencing_table_7000241 | fkey_reference_table.referenced_table2_7000234
- foreign_key_2_7000242 | fkey_reference_table.referencing_table_7000242 | fkey_reference_table.referenced_table2_7000234
+ fkey_ref_7000226      | fkey_reference_table.referencing_table_7000226 | fkey_reference_table.referenced_table_7000224
+ fkey_ref_7000227      | fkey_reference_table.referencing_table_7000227 | fkey_reference_table.referenced_table_7000224
+ fkey_ref_7000228      | fkey_reference_table.referencing_table_7000228 | fkey_reference_table.referenced_table_7000224
+ fkey_ref_7000229      | fkey_reference_table.referencing_table_7000229 | fkey_reference_table.referenced_table_7000224
+ fkey_ref_7000230      | fkey_reference_table.referencing_table_7000230 | fkey_reference_table.referenced_table_7000224
+ fkey_ref_7000231      | fkey_reference_table.referencing_table_7000231 | fkey_reference_table.referenced_table_7000224
+ fkey_ref_7000232      | fkey_reference_table.referencing_table_7000232 | fkey_reference_table.referenced_table_7000224
+ fkey_ref_7000233      | fkey_reference_table.referencing_table_7000233 | fkey_reference_table.referenced_table_7000224
+ foreign_key_2_7000226 | fkey_reference_table.referencing_table_7000226 | fkey_reference_table.referenced_table2_7000225
+ foreign_key_2_7000227 | fkey_reference_table.referencing_table_7000227 | fkey_reference_table.referenced_table2_7000225
+ foreign_key_2_7000228 | fkey_reference_table.referencing_table_7000228 | fkey_reference_table.referenced_table2_7000225
+ foreign_key_2_7000229 | fkey_reference_table.referencing_table_7000229 | fkey_reference_table.referenced_table2_7000225
+ foreign_key_2_7000230 | fkey_reference_table.referencing_table_7000230 | fkey_reference_table.referenced_table2_7000225
+ foreign_key_2_7000231 | fkey_reference_table.referencing_table_7000231 | fkey_reference_table.referenced_table2_7000225
+ foreign_key_2_7000232 | fkey_reference_table.referencing_table_7000232 | fkey_reference_table.referenced_table2_7000225
+ foreign_key_2_7000233 | fkey_reference_table.referencing_table_7000233 | fkey_reference_table.referenced_table2_7000225
 (16 rows)
 
 INSERT INTO referenced_table SELECT x, x+1 FROM generate_series(0,1000) AS f(x);
 INSERT INTO referenced_table2 SELECT x, x+1 FROM generate_series(500,1500) AS f(x);
 -- should fail
 INSERT INTO referencing_table SELECT x, x+1 FROM generate_series(0,1500) AS f(x);
-ERROR:  insert or update on table "referencing_table_7000242" violates foreign key constraint "foreign_key_2_7000242"
-DETAIL:  Key (id)=(9) is not present in table "referenced_table2_7000234".
+ERROR:  insert or update on table "referencing_table_7000227" violates foreign key constraint "foreign_key_2_7000227"
+DETAIL:  Key (id)=(5) is not present in table "referenced_table2_7000225".
 -- should fail
 INSERT INTO referencing_table SELECT x, x+1 FROM generate_series(0,400) AS f(x);
-ERROR:  insert or update on table "referencing_table_7000242" violates foreign key constraint "foreign_key_2_7000242"
-DETAIL:  Key (id)=(9) is not present in table "referenced_table2_7000234".
+ERROR:  insert or update on table "referencing_table_7000227" violates foreign key constraint "foreign_key_2_7000227"
+DETAIL:  Key (id)=(5) is not present in table "referenced_table2_7000225".
 -- should fail
 INSERT INTO referencing_table SELECT x, x+1 FROM generate_series(1000,1400) AS f(x);
-ERROR:  insert or update on table "referencing_table_7000242" violates foreign key constraint "fkey_ref_7000242"
-DETAIL:  Key (id)=(1023) is not present in table "referenced_table_7000233".
+ERROR:  insert or update on table "referencing_table_7000227" violates foreign key constraint "fkey_ref_7000227"
+DETAIL:  Key (id)=(1005) is not present in table "referenced_table_7000224".
 -- should success
 INSERT INTO referencing_table SELECT x, x+1 FROM generate_series(600,900) AS f(x);
 SELECT count(*) FROM referencing_table;
@@ -972,38 +949,38 @@ COMMIT;
 SELECT * FROM table_fkeys_in_workers WHERE relid LIKE 'fkey_reference_table.%' AND refd_relid LIKE 'fkey_reference_table.%' ORDER BY 1,2,3;
          name          |                     relid                      |                   refd_relid                   
 -----------------------+------------------------------------------------+------------------------------------------------
- fkey_ref_7000255      | fkey_reference_table.referencing_table_7000255 | fkey_reference_table.referenced_table_7000253
- fkey_ref_7000256      | fkey_reference_table.referencing_table_7000256 | fkey_reference_table.referenced_table_7000253
- fkey_ref_7000257      | fkey_reference_table.referencing_table_7000257 | fkey_reference_table.referenced_table_7000253
- fkey_ref_7000258      | fkey_reference_table.referencing_table_7000258 | fkey_reference_table.referenced_table_7000253
- fkey_ref_7000259      | fkey_reference_table.referencing_table_7000259 | fkey_reference_table.referenced_table_7000253
- fkey_ref_7000260      | fkey_reference_table.referencing_table_7000260 | fkey_reference_table.referenced_table_7000253
- fkey_ref_7000261      | fkey_reference_table.referencing_table_7000261 | fkey_reference_table.referenced_table_7000253
- fkey_ref_7000262      | fkey_reference_table.referencing_table_7000262 | fkey_reference_table.referenced_table_7000253
- foreign_key_2_7000255 | fkey_reference_table.referencing_table_7000255 | fkey_reference_table.referenced_table2_7000254
- foreign_key_2_7000256 | fkey_reference_table.referencing_table_7000256 | fkey_reference_table.referenced_table2_7000254
- foreign_key_2_7000257 | fkey_reference_table.referencing_table_7000257 | fkey_reference_table.referenced_table2_7000254
- foreign_key_2_7000258 | fkey_reference_table.referencing_table_7000258 | fkey_reference_table.referenced_table2_7000254
- foreign_key_2_7000259 | fkey_reference_table.referencing_table_7000259 | fkey_reference_table.referenced_table2_7000254
- foreign_key_2_7000260 | fkey_reference_table.referencing_table_7000260 | fkey_reference_table.referenced_table2_7000254
- foreign_key_2_7000261 | fkey_reference_table.referencing_table_7000261 | fkey_reference_table.referenced_table2_7000254
- foreign_key_2_7000262 | fkey_reference_table.referencing_table_7000262 | fkey_reference_table.referenced_table2_7000254
+ fkey_ref_7000246      | fkey_reference_table.referencing_table_7000246 | fkey_reference_table.referenced_table_7000244
+ fkey_ref_7000247      | fkey_reference_table.referencing_table_7000247 | fkey_reference_table.referenced_table_7000244
+ fkey_ref_7000248      | fkey_reference_table.referencing_table_7000248 | fkey_reference_table.referenced_table_7000244
+ fkey_ref_7000249      | fkey_reference_table.referencing_table_7000249 | fkey_reference_table.referenced_table_7000244
+ fkey_ref_7000250      | fkey_reference_table.referencing_table_7000250 | fkey_reference_table.referenced_table_7000244
+ fkey_ref_7000251      | fkey_reference_table.referencing_table_7000251 | fkey_reference_table.referenced_table_7000244
+ fkey_ref_7000252      | fkey_reference_table.referencing_table_7000252 | fkey_reference_table.referenced_table_7000244
+ fkey_ref_7000253      | fkey_reference_table.referencing_table_7000253 | fkey_reference_table.referenced_table_7000244
+ foreign_key_2_7000246 | fkey_reference_table.referencing_table_7000246 | fkey_reference_table.referenced_table2_7000245
+ foreign_key_2_7000247 | fkey_reference_table.referencing_table_7000247 | fkey_reference_table.referenced_table2_7000245
+ foreign_key_2_7000248 | fkey_reference_table.referencing_table_7000248 | fkey_reference_table.referenced_table2_7000245
+ foreign_key_2_7000249 | fkey_reference_table.referencing_table_7000249 | fkey_reference_table.referenced_table2_7000245
+ foreign_key_2_7000250 | fkey_reference_table.referencing_table_7000250 | fkey_reference_table.referenced_table2_7000245
+ foreign_key_2_7000251 | fkey_reference_table.referencing_table_7000251 | fkey_reference_table.referenced_table2_7000245
+ foreign_key_2_7000252 | fkey_reference_table.referencing_table_7000252 | fkey_reference_table.referenced_table2_7000245
+ foreign_key_2_7000253 | fkey_reference_table.referencing_table_7000253 | fkey_reference_table.referenced_table2_7000245
 (16 rows)
 
 INSERT INTO referenced_table SELECT x, x+1 FROM generate_series(0,1000) AS f(x);
 INSERT INTO referenced_table2 SELECT x, x+1 FROM generate_series(500,1500) AS f(x);
 -- should fail
 INSERT INTO referencing_table SELECT x, x+1 FROM generate_series(0,1500) AS f(x);
-ERROR:  insert or update on table "referencing_table_7000260" violates foreign key constraint "foreign_key_2_7000260"
-DETAIL:  Key (ref_id)=(7) is not present in table "referenced_table2_7000254".
+ERROR:  insert or update on table "referencing_table_7000251" violates foreign key constraint "foreign_key_2_7000251"
+DETAIL:  Key (ref_id)=(7) is not present in table "referenced_table2_7000245".
 -- should fail
 INSERT INTO referencing_table SELECT x, x+1 FROM generate_series(0,400) AS f(x);
-ERROR:  insert or update on table "referencing_table_7000260" violates foreign key constraint "foreign_key_2_7000260"
-DETAIL:  Key (ref_id)=(7) is not present in table "referenced_table2_7000254".
+ERROR:  insert or update on table "referencing_table_7000251" violates foreign key constraint "foreign_key_2_7000251"
+DETAIL:  Key (ref_id)=(7) is not present in table "referenced_table2_7000245".
 -- should fail
 INSERT INTO referencing_table SELECT x, x+1 FROM generate_series(1000,1400) AS f(x);
-ERROR:  insert or update on table "referencing_table_7000260" violates foreign key constraint "fkey_ref_7000260"
-DETAIL:  Key (id)=(1001) is not present in table "referenced_table_7000253".
+ERROR:  insert or update on table "referencing_table_7000251" violates foreign key constraint "fkey_ref_7000251"
+DETAIL:  Key (id)=(1001) is not present in table "referenced_table_7000244".
 -- should success
 INSERT INTO referencing_table SELECT x, x+501 FROM generate_series(0,1000) AS f(x);
 SELECT count(*) FROM referencing_table;
@@ -1105,43 +1082,43 @@ COMMIT;
 SELECT * FROM table_fkeys_in_workers WHERE relid LIKE 'fkey_reference_table.%' AND refd_relid LIKE 'fkey_reference_table.%' ORDER BY 1,2,3;
            name           |                      relid                      |                   refd_relid                   
 --------------------------+-------------------------------------------------+------------------------------------------------
- fkey_ref_7000274         | fkey_reference_table.referencing_table_7000274  | fkey_reference_table.referenced_table_7000273
- fkey_ref_7000275         | fkey_reference_table.referencing_table_7000275  | fkey_reference_table.referenced_table_7000273
- fkey_ref_7000276         | fkey_reference_table.referencing_table_7000276  | fkey_reference_table.referenced_table_7000273
- fkey_ref_7000277         | fkey_reference_table.referencing_table_7000277  | fkey_reference_table.referenced_table_7000273
- fkey_ref_7000278         | fkey_reference_table.referencing_table_7000278  | fkey_reference_table.referenced_table_7000273
- fkey_ref_7000279         | fkey_reference_table.referencing_table_7000279  | fkey_reference_table.referenced_table_7000273
- fkey_ref_7000280         | fkey_reference_table.referencing_table_7000280  | fkey_reference_table.referenced_table_7000273
- fkey_ref_7000281         | fkey_reference_table.referencing_table_7000281  | fkey_reference_table.referenced_table_7000273
- fkey_ref_7000282         | fkey_reference_table.referencing_table2_7000282 | fkey_reference_table.referenced_table_7000273
- fkey_ref_7000283         | fkey_reference_table.referencing_table2_7000283 | fkey_reference_table.referenced_table_7000273
- fkey_ref_7000284         | fkey_reference_table.referencing_table2_7000284 | fkey_reference_table.referenced_table_7000273
- fkey_ref_7000285         | fkey_reference_table.referencing_table2_7000285 | fkey_reference_table.referenced_table_7000273
- fkey_ref_7000286         | fkey_reference_table.referencing_table2_7000286 | fkey_reference_table.referenced_table_7000273
- fkey_ref_7000287         | fkey_reference_table.referencing_table2_7000287 | fkey_reference_table.referenced_table_7000273
- fkey_ref_7000288         | fkey_reference_table.referencing_table2_7000288 | fkey_reference_table.referenced_table_7000273
- fkey_ref_7000289         | fkey_reference_table.referencing_table2_7000289 | fkey_reference_table.referenced_table_7000273
- fkey_ref_to_dist_7000282 | fkey_reference_table.referencing_table2_7000282 | fkey_reference_table.referencing_table_7000274
- fkey_ref_to_dist_7000283 | fkey_reference_table.referencing_table2_7000283 | fkey_reference_table.referencing_table_7000275
- fkey_ref_to_dist_7000284 | fkey_reference_table.referencing_table2_7000284 | fkey_reference_table.referencing_table_7000276
- fkey_ref_to_dist_7000285 | fkey_reference_table.referencing_table2_7000285 | fkey_reference_table.referencing_table_7000277
- fkey_ref_to_dist_7000286 | fkey_reference_table.referencing_table2_7000286 | fkey_reference_table.referencing_table_7000278
- fkey_ref_to_dist_7000287 | fkey_reference_table.referencing_table2_7000287 | fkey_reference_table.referencing_table_7000279
- fkey_ref_to_dist_7000288 | fkey_reference_table.referencing_table2_7000288 | fkey_reference_table.referencing_table_7000280
- fkey_ref_to_dist_7000289 | fkey_reference_table.referencing_table2_7000289 | fkey_reference_table.referencing_table_7000281
+ fkey_ref_7000265         | fkey_reference_table.referencing_table_7000265  | fkey_reference_table.referenced_table_7000264
+ fkey_ref_7000266         | fkey_reference_table.referencing_table_7000266  | fkey_reference_table.referenced_table_7000264
+ fkey_ref_7000267         | fkey_reference_table.referencing_table_7000267  | fkey_reference_table.referenced_table_7000264
+ fkey_ref_7000268         | fkey_reference_table.referencing_table_7000268  | fkey_reference_table.referenced_table_7000264
+ fkey_ref_7000269         | fkey_reference_table.referencing_table_7000269  | fkey_reference_table.referenced_table_7000264
+ fkey_ref_7000270         | fkey_reference_table.referencing_table_7000270  | fkey_reference_table.referenced_table_7000264
+ fkey_ref_7000271         | fkey_reference_table.referencing_table_7000271  | fkey_reference_table.referenced_table_7000264
+ fkey_ref_7000272         | fkey_reference_table.referencing_table_7000272  | fkey_reference_table.referenced_table_7000264
+ fkey_ref_7000273         | fkey_reference_table.referencing_table2_7000273 | fkey_reference_table.referenced_table_7000264
+ fkey_ref_7000274         | fkey_reference_table.referencing_table2_7000274 | fkey_reference_table.referenced_table_7000264
+ fkey_ref_7000275         | fkey_reference_table.referencing_table2_7000275 | fkey_reference_table.referenced_table_7000264
+ fkey_ref_7000276         | fkey_reference_table.referencing_table2_7000276 | fkey_reference_table.referenced_table_7000264
+ fkey_ref_7000277         | fkey_reference_table.referencing_table2_7000277 | fkey_reference_table.referenced_table_7000264
+ fkey_ref_7000278         | fkey_reference_table.referencing_table2_7000278 | fkey_reference_table.referenced_table_7000264
+ fkey_ref_7000279         | fkey_reference_table.referencing_table2_7000279 | fkey_reference_table.referenced_table_7000264
+ fkey_ref_7000280         | fkey_reference_table.referencing_table2_7000280 | fkey_reference_table.referenced_table_7000264
+ fkey_ref_to_dist_7000273 | fkey_reference_table.referencing_table2_7000273 | fkey_reference_table.referencing_table_7000265
+ fkey_ref_to_dist_7000274 | fkey_reference_table.referencing_table2_7000274 | fkey_reference_table.referencing_table_7000266
+ fkey_ref_to_dist_7000275 | fkey_reference_table.referencing_table2_7000275 | fkey_reference_table.referencing_table_7000267
+ fkey_ref_to_dist_7000276 | fkey_reference_table.referencing_table2_7000276 | fkey_reference_table.referencing_table_7000268
+ fkey_ref_to_dist_7000277 | fkey_reference_table.referencing_table2_7000277 | fkey_reference_table.referencing_table_7000269
+ fkey_ref_to_dist_7000278 | fkey_reference_table.referencing_table2_7000278 | fkey_reference_table.referencing_table_7000270
+ fkey_ref_to_dist_7000279 | fkey_reference_table.referencing_table2_7000279 | fkey_reference_table.referencing_table_7000271
+ fkey_ref_to_dist_7000280 | fkey_reference_table.referencing_table2_7000280 | fkey_reference_table.referencing_table_7000272
 (24 rows)
 
 INSERT INTO referenced_table SELECT x, x+1 FROM generate_series(0,1000) AS f(x);
 -- should fail
 INSERT INTO referencing_table2 SELECT x, x+1 FROM generate_series(0,100) AS f(x);
-ERROR:  insert or update on table "referencing_table2_7000284" violates foreign key constraint "fkey_ref_to_dist_7000284"
-DETAIL:  Key (id)=(4) is not present in table "referencing_table_7000276".
+ERROR:  insert or update on table "referencing_table2_7000274" violates foreign key constraint "fkey_ref_to_dist_7000274"
+DETAIL:  Key (id)=(5) is not present in table "referencing_table_7000266".
 -- should success
 INSERT INTO referencing_table SELECT x, x+1 FROM generate_series(0,400) AS f(x);
 -- should fail
 INSERT INTO referencing_table2 SELECT x, x+1 FROM generate_series(200,500) AS f(x);
-ERROR:  insert or update on table "referencing_table2_7000284" violates foreign key constraint "fkey_ref_to_dist_7000284"
-DETAIL:  Key (id)=(408) is not present in table "referencing_table_7000276".
+ERROR:  insert or update on table "referencing_table2_7000274" violates foreign key constraint "fkey_ref_to_dist_7000274"
+DETAIL:  Key (id)=(403) is not present in table "referencing_table_7000266".
 -- should success
 INSERT INTO referencing_table2 SELECT x, x+1 FROM generate_series(0,300) AS f(x);
 DELETE FROM referenced_table WHERE test_column < 200;
@@ -1239,22 +1216,22 @@ ALTER TABLE referencing_table ADD CONSTRAINT fkey_ref FOREIGN KEY (ref_id, ref_i
 SELECT * FROM table_fkeys_in_workers WHERE relid LIKE 'fkey_reference_table.referencing%' ORDER BY 1,2,3;
                      name                      |                           relid                            |                   refd_relid                   
 -----------------------------------------------+------------------------------------------------------------+------------------------------------------------
- fkey_ref_7000308                              | fkey_reference_table.referencing_table_7000308             | fkey_reference_table.referenced_table_7000307
- fkey_ref_7000309                              | fkey_reference_table.referencing_table_7000309             | fkey_reference_table.referenced_table_7000307
- fkey_ref_7000310                              | fkey_reference_table.referencing_table_7000310             | fkey_reference_table.referenced_table_7000307
- fkey_ref_7000311                              | fkey_reference_table.referencing_table_7000311             | fkey_reference_table.referenced_table_7000307
- fkey_ref_7000312                              | fkey_reference_table.referencing_table_7000312             | fkey_reference_table.referenced_table_7000307
- fkey_ref_7000313                              | fkey_reference_table.referencing_table_7000313             | fkey_reference_table.referenced_table_7000307
- fkey_ref_7000314                              | fkey_reference_table.referencing_table_7000314             | fkey_reference_table.referenced_table_7000307
- fkey_ref_7000315                              | fkey_reference_table.referencing_table_7000315             | fkey_reference_table.referenced_table_7000307
- referencing_referencing_table_id_fkey_7000316 | fkey_reference_table.referencing_referencing_table_7000316 | fkey_reference_table.referencing_table_7000308
- referencing_referencing_table_id_fkey_7000317 | fkey_reference_table.referencing_referencing_table_7000317 | fkey_reference_table.referencing_table_7000309
- referencing_referencing_table_id_fkey_7000318 | fkey_reference_table.referencing_referencing_table_7000318 | fkey_reference_table.referencing_table_7000310
- referencing_referencing_table_id_fkey_7000319 | fkey_reference_table.referencing_referencing_table_7000319 | fkey_reference_table.referencing_table_7000311
- referencing_referencing_table_id_fkey_7000320 | fkey_reference_table.referencing_referencing_table_7000320 | fkey_reference_table.referencing_table_7000312
- referencing_referencing_table_id_fkey_7000321 | fkey_reference_table.referencing_referencing_table_7000321 | fkey_reference_table.referencing_table_7000313
- referencing_referencing_table_id_fkey_7000322 | fkey_reference_table.referencing_referencing_table_7000322 | fkey_reference_table.referencing_table_7000314
- referencing_referencing_table_id_fkey_7000323 | fkey_reference_table.referencing_referencing_table_7000323 | fkey_reference_table.referencing_table_7000315
+ fkey_ref_7000299                              | fkey_reference_table.referencing_table_7000299             | fkey_reference_table.referenced_table_7000298
+ fkey_ref_7000300                              | fkey_reference_table.referencing_table_7000300             | fkey_reference_table.referenced_table_7000298
+ fkey_ref_7000301                              | fkey_reference_table.referencing_table_7000301             | fkey_reference_table.referenced_table_7000298
+ fkey_ref_7000302                              | fkey_reference_table.referencing_table_7000302             | fkey_reference_table.referenced_table_7000298
+ fkey_ref_7000303                              | fkey_reference_table.referencing_table_7000303             | fkey_reference_table.referenced_table_7000298
+ fkey_ref_7000304                              | fkey_reference_table.referencing_table_7000304             | fkey_reference_table.referenced_table_7000298
+ fkey_ref_7000305                              | fkey_reference_table.referencing_table_7000305             | fkey_reference_table.referenced_table_7000298
+ fkey_ref_7000306                              | fkey_reference_table.referencing_table_7000306             | fkey_reference_table.referenced_table_7000298
+ referencing_referencing_table_id_fkey_7000307 | fkey_reference_table.referencing_referencing_table_7000307 | fkey_reference_table.referencing_table_7000299
+ referencing_referencing_table_id_fkey_7000308 | fkey_reference_table.referencing_referencing_table_7000308 | fkey_reference_table.referencing_table_7000300
+ referencing_referencing_table_id_fkey_7000309 | fkey_reference_table.referencing_referencing_table_7000309 | fkey_reference_table.referencing_table_7000301
+ referencing_referencing_table_id_fkey_7000310 | fkey_reference_table.referencing_referencing_table_7000310 | fkey_reference_table.referencing_table_7000302
+ referencing_referencing_table_id_fkey_7000311 | fkey_reference_table.referencing_referencing_table_7000311 | fkey_reference_table.referencing_table_7000303
+ referencing_referencing_table_id_fkey_7000312 | fkey_reference_table.referencing_referencing_table_7000312 | fkey_reference_table.referencing_table_7000304
+ referencing_referencing_table_id_fkey_7000313 | fkey_reference_table.referencing_referencing_table_7000313 | fkey_reference_table.referencing_table_7000305
+ referencing_referencing_table_id_fkey_7000314 | fkey_reference_table.referencing_referencing_table_7000314 | fkey_reference_table.referencing_table_7000306
 (16 rows)
 
 INSERT INTO referenced_table SELECT x, x+1 FROM generate_series(1,1000) AS f(x);
diff --git a/src/test/regress/expected/isolation_validate_vs_insert.out b/src/test/regress/expected/isolation_validate_vs_insert.out
new file mode 100644
index 000000000..212edbedf
--- /dev/null
+++ b/src/test/regress/expected/isolation_validate_vs_insert.out
@@ -0,0 +1,59 @@
+Parsed test spec with 2 sessions
+
+starting permutation: s1-initialize s1-add-constraint s1-begin s2-begin s1-validate s2-insert s1-commit s2-commit
+create_distributed_table
+
+               
+step s1-initialize: INSERT INTO constrained_table VALUES (0, 0), (1, 1), (2, 2), (3, 4);
+step s1-add-constraint: ALTER TABLE constrained_table ADD CONSTRAINT check_constraint CHECK(int_data<30) NOT VALID;
+step s1-begin: BEGIN;
+step s2-begin: BEGIN;
+step s1-validate: ALTER TABLE constrained_table VALIDATE CONSTRAINT check_constraint;
+step s2-insert: INSERT INTO constrained_table VALUES(10, 10);
+step s1-commit: COMMIT;
+step s2-commit: COMMIT;
+
+starting permutation: s1-initialize s1-add-constraint s1-begin s2-begin s1-validate s2-select s1-commit s2-commit
+create_distributed_table
+
+               
+step s1-initialize: INSERT INTO constrained_table VALUES (0, 0), (1, 1), (2, 2), (3, 4);
+step s1-add-constraint: ALTER TABLE constrained_table ADD CONSTRAINT check_constraint CHECK(int_data<30) NOT VALID;
+step s1-begin: BEGIN;
+step s2-begin: BEGIN;
+step s1-validate: ALTER TABLE constrained_table VALIDATE CONSTRAINT check_constraint;
+step s2-select: SELECT sum(int_data) FROM constrained_table;
+sum            
+
+7              
+step s1-commit: COMMIT;
+step s2-commit: COMMIT;
+
+starting permutation: s1-initialize s1-add-constraint s1-begin s2-begin s2-insert s1-validate s1-commit s2-commit
+create_distributed_table
+
+               
+step s1-initialize: INSERT INTO constrained_table VALUES (0, 0), (1, 1), (2, 2), (3, 4);
+step s1-add-constraint: ALTER TABLE constrained_table ADD CONSTRAINT check_constraint CHECK(int_data<30) NOT VALID;
+step s1-begin: BEGIN;
+step s2-begin: BEGIN;
+step s2-insert: INSERT INTO constrained_table VALUES(10, 10);
+step s1-validate: ALTER TABLE constrained_table VALIDATE CONSTRAINT check_constraint;
+step s1-commit: COMMIT;
+step s2-commit: COMMIT;
+
+starting permutation: s1-initialize s1-add-constraint s1-begin s2-begin s2-select s1-validate s1-commit s2-commit
+create_distributed_table
+
+               
+step s1-initialize: INSERT INTO constrained_table VALUES (0, 0), (1, 1), (2, 2), (3, 4);
+step s1-add-constraint: ALTER TABLE constrained_table ADD CONSTRAINT check_constraint CHECK(int_data<30) NOT VALID;
+step s1-begin: BEGIN;
+step s2-begin: BEGIN;
+step s2-select: SELECT sum(int_data) FROM constrained_table;
+sum            
+
+7              
+step s1-validate: ALTER TABLE constrained_table VALIDATE CONSTRAINT check_constraint;
+step s1-commit: COMMIT;
+step s2-commit: COMMIT;
diff --git a/src/test/regress/expected/multi_reference_table.out b/src/test/regress/expected/multi_reference_table.out
index d13c5bab3..920a8a9c2 100644
--- a/src/test/regress/expected/multi_reference_table.out
+++ b/src/test/regress/expected/multi_reference_table.out
@@ -1385,7 +1385,7 @@ SELECT "Column", "Type", "Modifiers" FROM table_desc WHERE relid='reference_sche
 -- as we expect, setting WITH OIDS does not work for reference tables
 ALTER TABLE reference_schema.reference_table_ddl SET WITH OIDS;
 ERROR:  alter table command is currently unsupported
-DETAIL:  Only ADD|DROP COLUMN, SET|DROP NOT NULL, SET|DROP DEFAULT, ADD|DROP CONSTRAINT, SET (), RESET (), ATTACH|DETACH PARTITION and TYPE subcommands are supported.
+DETAIL:  Only ADD|DROP COLUMN, SET|DROP NOT NULL, SET|DROP DEFAULT, ADD|DROP|VALIDATE CONSTRAINT, SET (), RESET (), ATTACH|DETACH PARTITION and TYPE subcommands are supported.
 -- now test the renaming of the table, and back to the expected name
 ALTER TABLE reference_schema.reference_table_ddl RENAME TO reference_table_ddl_test;
 ALTER TABLE reference_schema.reference_table_ddl_test RENAME TO reference_table_ddl;
diff --git a/src/test/regress/expected/multi_test_helpers.out b/src/test/regress/expected/multi_test_helpers.out
index 40073f61e..c72a4487b 100644
--- a/src/test/regress/expected/multi_test_helpers.out
+++ b/src/test/regress/expected/multi_test_helpers.out
@@ -17,7 +17,8 @@ SELECT rc.constraint_name AS "name",
        kcu.column_name AS "column_name",
        uc_kcu.column_name AS "refd_column_name",
        format('%I.%I', kcu.table_schema, kcu.table_name)::regclass::oid AS relid,
-       format('%I.%I', uc_kcu.table_schema, uc_kcu.table_name)::regclass::oid AS refd_relid
+       format('%I.%I', uc_kcu.table_schema, uc_kcu.table_name)::regclass::oid AS refd_relid,
+       rc.constraint_schema AS "schema"
 FROM information_schema.referential_constraints rc,
      information_schema.key_column_usage kcu,
      information_schema.key_column_usage uc_kcu
diff --git a/src/test/regress/expected/validate_constraint.out b/src/test/regress/expected/validate_constraint.out
new file mode 100644
index 000000000..ad180b13b
--- /dev/null
+++ b/src/test/regress/expected/validate_constraint.out
@@ -0,0 +1,150 @@
+--
+--  VALIDATE_CONSTRAINT
+--
+-- PostgreSQL 11 Docs Excerpt:
+-- The queries that can have 'NOT VALID' option are of the form:
+-- ALTER TABLE [ IF EXISTS ] [ ONLY ] name [ * ] ADD table_constraint NOT VALID [, ...]
+--
+-- where table_constraint is:
+--   [ CONSTRAINT constraint_name ]
+--   { CHECK ( expression ) [ NO INHERIT ] |
+--     UNIQUE ( column_name [, ... ] ) index_parameters |
+--     PRIMARY KEY ( column_name [, ... ] ) index_parameters |
+--     EXCLUDE [ USING index_method ] ( exclude_element WITH operator [, ... ] ) index_parameters [ WHERE ( predicate ) ] |
+--     FOREIGN KEY ( column_name [, ... ] ) REFERENCES reftable [ ( refcolumn [, ... ] ) ]
+--       [ MATCH FULL | MATCH PARTIAL | MATCH SIMPLE ] [ ON DELETE action ] [ ON UPDATE action ] }
+--   [ DEFERRABLE | NOT DEFERRABLE ] [ INITIALLY DEFERRED | INITIALLY IMMEDIATE ]
+-- This form adds a new constraint to a table using the same syntax as CREATE TABLE, plus the option NOT VALID, which is
+-- currently only allowed for foreign key and CHECK constraints. If the constraint is marked NOT VALID, the
+-- potentially-lengthy initial check to verify that all rows in the table satisfy the constraint is skipped.
+-- The constraint will still be enforced against subsequent inserts or updates (that is, they'll fail unless there is a
+-- matching row in the referenced table, in the case of foreign keys; and they'll fail unless the new row matches the
+-- specified check constraints). But the database will not assume that the constraint holds for all rows in the table,
+-- until it is validated by using the VALIDATE CONSTRAINT option.
+CREATE SCHEMA validate_constraint;
+SET search_path TO 'validate_constraint';
+SET citus.shard_replication_factor TO 1;
+SET citus.shard_count TO 8;
+SET citus.next_shard_id TO 8000000;
+SET citus.next_placement_id TO 8000000;
+CREATE TYPE constraint_validity AS (name text, validated bool);
+SELECT run_command_on_workers(
+         $$CREATE TYPE constraint_validity AS (name text, validated bool)$$);
+      run_command_on_workers       
+-----------------------------------
+ (localhost,57637,t,"CREATE TYPE")
+ (localhost,57638,t,"CREATE TYPE")
+(2 rows)
+
+CREATE VIEW constraint_validations_in_workers AS
+  SELECT (json_populate_record(NULL :: constraint_validity,
+                               json_array_elements_text((run_command_on_workers($$
+    SELECT
+      COALESCE(json_agg(row_to_json(d)), '[]'::json)
+    FROM
+      (
+        SELECT conname as name,
+        convalidated as validated
+        FROM pg_catalog.pg_constraint AS con
+        JOIN pg_catalog.pg_namespace AS ns
+        ON ns.oid = con.connamespace
+        WHERE nspname = 'validate_constraint'
+        AND contype = 'c'
+        ORDER BY 1,2
+      )
+      d $$)).RESULT :: json) :: json)).*
+    ORDER BY 1,2;
+CREATE VIEW constraint_validations AS
+  SELECT conname as "Constraint",
+         convalidated as "Validated?"
+  FROM pg_catalog.pg_constraint AS con
+         JOIN pg_catalog.pg_namespace AS ns ON ns.oid = con.connamespace
+  WHERE nspname = 'validate_constraint'
+    AND contype = 'c';
+CREATE TABLE referenced_table (id int UNIQUE, test_column int);
+SELECT create_reference_table('referenced_table');
+ create_reference_table 
+------------------------
+ 
+(1 row)
+
+CREATE TABLE referencing_table (id int, ref_id int);
+SELECT create_distributed_table('referencing_table', 'ref_id');
+ create_distributed_table 
+--------------------------
+ 
+(1 row)
+
+CREATE TABLE constrained_table (id int, constrained_column int);
+SELECT create_distributed_table('constrained_table', 'constrained_column');
+ create_distributed_table 
+--------------------------
+ 
+(1 row)
+
+-- The two constraint types that are allowed to be NOT VALID
+BEGIN;
+ALTER TABLE constrained_table
+  ADD CONSTRAINT check_constraint CHECK (constrained_column > 100) NOT VALID;
+ALTER TABLE constrained_table
+  VALIDATE CONSTRAINT check_constraint;
+ROLLBACK;
+BEGIN;
+ALTER TABLE referencing_table
+  ADD CONSTRAINT fk_constraint FOREIGN KEY (ref_id) REFERENCES referenced_table (id) NOT VALID;
+ALTER TABLE referencing_table
+  VALIDATE CONSTRAINT fk_constraint;
+ROLLBACK;
+-- It is possible that some other table_constraint commands will support NOT VALID option in the future
+-- These should fail as Postgres does not yet allow these constraints to be NOT VALID
+-- If one of these queries are not failing on a future Postgres version, we will need to test corresponding VALIDATE CONSTRAINT queries
+ALTER TABLE constrained_table
+  ADD CONSTRAINT unique_constraint UNIQUE (constrained_column) NOT VALID;
+ERROR:  UNIQUE constraints cannot be marked NOT VALID
+ALTER TABLE constrained_table
+  ADD CONSTRAINT pk_constraint PRIMARY KEY (id) NOT VALID;
+ERROR:  PRIMARY KEY constraints cannot be marked NOT VALID
+ALTER TABLE constrained_table
+  ADD CONSTRAINT exclude_constraint EXCLUDE USING gist (id WITH =, constrained_column WITH <>) NOT VALID;
+ERROR:  EXCLUDE constraints cannot be marked NOT VALID
+INSERT INTO constrained_table
+SELECT x, x
+from generate_series(1, 1000) as f (x);
+-- a constraint that can be validated
+ALTER TABLE constrained_table
+  ADD CONSTRAINT validatable_constraint CHECK (constrained_column < 10000) NOT VALID;
+ALTER TABLE constrained_table
+  VALIDATE CONSTRAINT validatable_constraint;
+-- Check which constraints are validated
+SELECT *
+FROM constraint_validations
+ORDER BY 1, 2;
+       Constraint       | Validated? 
+------------------------+------------
+ validatable_constraint | t
+(1 row)
+
+SELECT *
+FROM constraint_validations_in_workers
+ORDER BY 1, 2;
+              name              | validated 
+--------------------------------+-----------
+ validatable_constraint_8000009 | t
+ validatable_constraint_8000010 | t
+ validatable_constraint_8000011 | t
+ validatable_constraint_8000012 | t
+ validatable_constraint_8000013 | t
+ validatable_constraint_8000014 | t
+ validatable_constraint_8000015 | t
+ validatable_constraint_8000016 | t
+(8 rows)
+
+DROP TABLE constrained_table;
+DROP TABLE referenced_table CASCADE;
+DROP TABLE referencing_table;
+DROP SCHEMA validate_constraint CASCADE;
+NOTICE:  drop cascades to 3 other objects
+DETAIL:  drop cascades to type constraint_validity
+drop cascades to view constraint_validations_in_workers
+drop cascades to view constraint_validations
+SET search_path TO DEFAULT;
diff --git a/src/test/regress/isolation_schedule b/src/test/regress/isolation_schedule
index d8d677beb..86cb914b2 100644
--- a/src/test/regress/isolation_schedule
+++ b/src/test/regress/isolation_schedule
@@ -43,6 +43,7 @@ test: isolation_truncate_vs_all
 test: isolation_drop_vs_all
 test: isolation_ddl_vs_all
 test: isolation_citus_dist_activity
+test: isolation_validate_vs_insert
 
 # MX tests
 test: isolation_reference_on_mx
diff --git a/src/test/regress/multi_schedule b/src/test/regress/multi_schedule
index f438ec6dd..0bc772b5d 100644
--- a/src/test/regress/multi_schedule
+++ b/src/test/regress/multi_schedule
@@ -173,7 +173,7 @@ test: multi_modifications
 test: multi_distribution_metadata
 test: multi_generate_ddl_commands multi_create_shards multi_prune_shard_list multi_repair_shards 
 test: multi_upsert multi_simple_queries multi_create_insert_proxy multi_data_types
-test: multi_utilities foreign_key_to_reference_table
+test: multi_utilities foreign_key_to_reference_table validate_constraint
 test: multi_modifying_xacts
 test: multi_repartition_udt multi_repartitioned_subquery_udf multi_subtransactions
 test: multi_transaction_recovery
diff --git a/src/test/regress/output/multi_alter_table_statements.source b/src/test/regress/output/multi_alter_table_statements.source
index 1975ddf87..4a3954028 100644
--- a/src/test/regress/output/multi_alter_table_statements.source
+++ b/src/test/regress/output/multi_alter_table_statements.source
@@ -344,7 +344,7 @@ SELECT "Column", "Type", "Modifiers" FROM table_desc WHERE relid='public.lineite
 ALTER TABLE lineitem_alter ADD COLUMN int_column3 INTEGER,
 	ALTER COLUMN int_column1 SET STATISTICS 10;
 ERROR:  alter table command is currently unsupported
-DETAIL:  Only ADD|DROP COLUMN, SET|DROP NOT NULL, SET|DROP DEFAULT, ADD|DROP CONSTRAINT, SET (), RESET (), ATTACH|DETACH PARTITION and TYPE subcommands are supported.
+DETAIL:  Only ADD|DROP COLUMN, SET|DROP NOT NULL, SET|DROP DEFAULT, ADD|DROP|VALIDATE CONSTRAINT, SET (), RESET (), ATTACH|DETACH PARTITION and TYPE subcommands are supported.
 ALTER TABLE lineitem_alter DROP COLUMN int_column1, DROP COLUMN int_column2;
 SELECT "Column", "Type", "Modifiers" FROM table_desc WHERE relid='public.lineitem_alter'::regclass;
      Column      |         Type          | Modifiers 
@@ -376,12 +376,12 @@ ERROR:  cannot execute ALTER TABLE command involving partition column
 -- Verify that we error out on unsupported statement types
 ALTER TABLE lineitem_alter ALTER COLUMN l_orderkey SET STATISTICS 100;
 ERROR:  alter table command is currently unsupported
-DETAIL:  Only ADD|DROP COLUMN, SET|DROP NOT NULL, SET|DROP DEFAULT, ADD|DROP CONSTRAINT, SET (), RESET (), ATTACH|DETACH PARTITION and TYPE subcommands are supported.
+DETAIL:  Only ADD|DROP COLUMN, SET|DROP NOT NULL, SET|DROP DEFAULT, ADD|DROP|VALIDATE CONSTRAINT, SET (), RESET (), ATTACH|DETACH PARTITION and TYPE subcommands are supported.
 ALTER TABLE lineitem_alter DROP CONSTRAINT IF EXISTS non_existent_contraint;
 NOTICE:  constraint "non_existent_contraint" of relation "lineitem_alter" does not exist, skipping
 ALTER TABLE lineitem_alter SET WITHOUT OIDS;
 ERROR:  alter table command is currently unsupported
-DETAIL:  Only ADD|DROP COLUMN, SET|DROP NOT NULL, SET|DROP DEFAULT, ADD|DROP CONSTRAINT, SET (), RESET (), ATTACH|DETACH PARTITION and TYPE subcommands are supported.
+DETAIL:  Only ADD|DROP COLUMN, SET|DROP NOT NULL, SET|DROP DEFAULT, ADD|DROP|VALIDATE CONSTRAINT, SET (), RESET (), ATTACH|DETACH PARTITION and TYPE subcommands are supported.
 -- Verify that we error out in case of postgres errors on supported statement
 -- types
 ALTER TABLE lineitem_alter ADD COLUMN new_column non_existent_type;
diff --git a/src/test/regress/specs/isolation_validate_vs_insert.spec b/src/test/regress/specs/isolation_validate_vs_insert.spec
new file mode 100644
index 000000000..81d2d1c77
--- /dev/null
+++ b/src/test/regress/specs/isolation_validate_vs_insert.spec
@@ -0,0 +1,39 @@
+#
+# How we organize this isolation test spec, is explained at README.md file in this directory.
+#
+
+# create distributed table to test behavior of VALIDATE in concurrent operations
+setup
+{
+	SET citus.shard_replication_factor TO 1;
+	CREATE TABLE constrained_table(id integer, int_data int);
+	SELECT create_distributed_table('constrained_table', 'id');
+}
+
+# drop distributed table
+teardown
+{
+	DROP TABLE IF EXISTS constrained_table CASCADE;
+}
+
+# session 1
+session "s1"
+step "s1-initialize" { INSERT INTO constrained_table VALUES (0, 0), (1, 1), (2, 2), (3, 4); }
+step "s1-begin" { BEGIN; }
+step "s1-add-constraint" { ALTER TABLE constrained_table ADD CONSTRAINT check_constraint CHECK(int_data<30) NOT VALID; }
+step "s1-validate" { ALTER TABLE constrained_table VALIDATE CONSTRAINT check_constraint; }
+step "s1-commit" { COMMIT; }
+
+# session 2
+session "s2"
+step "s2-begin" { BEGIN; }
+step "s2-insert" { INSERT INTO constrained_table VALUES(10, 10); }
+step "s2-insert-invalid" { INSERT INTO constrained_table VALUES(100, 100); }
+step "s2-select" { SELECT sum(int_data) FROM constrained_table; }
+step "s2-commit" { COMMIT; }
+
+# permutations - check read and write are not blocked during validate queries
+permutation "s1-initialize" "s1-add-constraint" "s1-begin" "s2-begin" "s1-validate" "s2-insert" "s1-commit" "s2-commit"
+permutation "s1-initialize" "s1-add-constraint" "s1-begin" "s2-begin" "s1-validate" "s2-select" "s1-commit" "s2-commit"
+permutation "s1-initialize" "s1-add-constraint" "s1-begin" "s2-begin" "s2-insert" "s1-validate" "s1-commit" "s2-commit"
+permutation "s1-initialize" "s1-add-constraint" "s1-begin" "s2-begin" "s2-select" "s1-validate" "s1-commit" "s2-commit"
diff --git a/src/test/regress/sql/foreign_key_to_reference_table.sql b/src/test/regress/sql/foreign_key_to_reference_table.sql
index 88948cfe7..07924bdb5 100644
--- a/src/test/regress/sql/foreign_key_to_reference_table.sql
+++ b/src/test/regress/sql/foreign_key_to_reference_table.sql
@@ -1,6 +1,8 @@
 --
 -- FOREIGN_KEY_TO_REFERENCE_TABLE
 --
+SHOW server_version \gset
+SELECT substring(:'server_version', '\d+')::int > 9 AS version_above_nine;
 
 CREATE SCHEMA fkey_reference_table;
 SET search_path TO 'fkey_reference_table';
@@ -25,7 +27,9 @@ SELECT
           relid::regclass::text,
           refd_relid::regclass::text
         FROM
-          table_fkey_cols 
+          table_fkey_cols
+        WHERE
+          "schema" = 'fkey_reference_table'
       )
       d $$ )).RESULT::json )::json )).* ;
 
@@ -362,27 +366,6 @@ INSERT INTO referencing_table SELECT x,(random()*1000)::int FROM generate_series
 DROP TABLE referenced_table CASCADE;
 DROP TABLE referencing_table CASCADE;
 
--- In the following test, we show that Citus currently does not support 
--- VALIDATE command.
-CREATE TABLE referenced_table(test_column int, test_column2 int, PRIMARY KEY(test_column));
-CREATE TABLE referencing_table(id int, ref_id int DEFAULT -1);
-SELECT create_reference_table('referenced_table');
-SELECT create_distributed_table('referencing_table', 'id');
-ALTER TABLE referencing_table ADD CONSTRAINT fkey_ref FOREIGN KEY (ref_id) REFERENCES referenced_table(test_column) ON DELETE SET DEFAULT NOT VALID;
-
--- Even if the foreign constraint is added with "NOT VALID",
--- we make sure that it is still applied to the upcoming inserts.
-INSERT INTO referenced_table SELECT x, x FROM generate_series(0,1000) AS f(x);
-INSERT INTO referencing_table SELECT x, x FROM generate_series(0,1000) AS f(x);
--- we expect this to fail because of the foreign constraint.
-INSERT INTO referencing_table SELECT x, x FROM generate_series(1000,1001) AS f(x);
-
--- currently not supported
-ALTER TABLE referencing_table VALIDATE CONSTRAINT fkey_ref;
-
-DROP TABLE referenced_table CASCADE;
-DROP TABLE referencing_table CASCADE;
-
 -- In the following tests, we create a foreign constraint with 
 -- ON UPDATE CASCADE and see if it works properly with cascading upsert
 CREATE TABLE referenced_table(test_column int, test_column2 int, PRIMARY KEY(test_column));
diff --git a/src/test/regress/sql/multi_test_helpers.sql b/src/test/regress/sql/multi_test_helpers.sql
index 26bb17882..8577ec74b 100644
--- a/src/test/regress/sql/multi_test_helpers.sql
+++ b/src/test/regress/sql/multi_test_helpers.sql
@@ -19,7 +19,8 @@ SELECT rc.constraint_name AS "name",
        kcu.column_name AS "column_name",
        uc_kcu.column_name AS "refd_column_name",
        format('%I.%I', kcu.table_schema, kcu.table_name)::regclass::oid AS relid,
-       format('%I.%I', uc_kcu.table_schema, uc_kcu.table_name)::regclass::oid AS refd_relid
+       format('%I.%I', uc_kcu.table_schema, uc_kcu.table_name)::regclass::oid AS refd_relid,
+       rc.constraint_schema AS "schema"
 FROM information_schema.referential_constraints rc,
      information_schema.key_column_usage kcu,
      information_schema.key_column_usage uc_kcu
diff --git a/src/test/regress/sql/validate_constraint.sql b/src/test/regress/sql/validate_constraint.sql
new file mode 100644
index 000000000..f2447285b
--- /dev/null
+++ b/src/test/regress/sql/validate_constraint.sql
@@ -0,0 +1,126 @@
+--
+--  VALIDATE_CONSTRAINT
+--
+
+-- PostgreSQL 11 Docs Excerpt:
+
+-- The queries that can have 'NOT VALID' option are of the form:
+-- ALTER TABLE [ IF EXISTS ] [ ONLY ] name [ * ] ADD table_constraint NOT VALID [, ...]
+--
+-- where table_constraint is:
+--   [ CONSTRAINT constraint_name ]
+--   { CHECK ( expression ) [ NO INHERIT ] |
+--     UNIQUE ( column_name [, ... ] ) index_parameters |
+--     PRIMARY KEY ( column_name [, ... ] ) index_parameters |
+--     EXCLUDE [ USING index_method ] ( exclude_element WITH operator [, ... ] ) index_parameters [ WHERE ( predicate ) ] |
+--     FOREIGN KEY ( column_name [, ... ] ) REFERENCES reftable [ ( refcolumn [, ... ] ) ]
+--       [ MATCH FULL | MATCH PARTIAL | MATCH SIMPLE ] [ ON DELETE action ] [ ON UPDATE action ] }
+--   [ DEFERRABLE | NOT DEFERRABLE ] [ INITIALLY DEFERRED | INITIALLY IMMEDIATE ]
+
+-- This form adds a new constraint to a table using the same syntax as CREATE TABLE, plus the option NOT VALID, which is
+-- currently only allowed for foreign key and CHECK constraints. If the constraint is marked NOT VALID, the
+-- potentially-lengthy initial check to verify that all rows in the table satisfy the constraint is skipped.
+
+-- The constraint will still be enforced against subsequent inserts or updates (that is, they'll fail unless there is a
+-- matching row in the referenced table, in the case of foreign keys; and they'll fail unless the new row matches the
+-- specified check constraints). But the database will not assume that the constraint holds for all rows in the table,
+-- until it is validated by using the VALIDATE CONSTRAINT option.
+
+CREATE SCHEMA validate_constraint;
+SET search_path TO 'validate_constraint';
+SET citus.shard_replication_factor TO 1;
+SET citus.shard_count TO 8;
+SET citus.next_shard_id TO 8000000;
+SET citus.next_placement_id TO 8000000;
+
+CREATE TYPE constraint_validity AS (name text, validated bool);
+SELECT run_command_on_workers(
+         $$CREATE TYPE constraint_validity AS (name text, validated bool)$$);
+
+CREATE VIEW constraint_validations_in_workers AS
+  SELECT (json_populate_record(NULL :: constraint_validity,
+                               json_array_elements_text((run_command_on_workers($$
+    SELECT
+      COALESCE(json_agg(row_to_json(d)), '[]'::json)
+    FROM
+      (
+        SELECT conname as name,
+        convalidated as validated
+        FROM pg_catalog.pg_constraint AS con
+        JOIN pg_catalog.pg_namespace AS ns
+        ON ns.oid = con.connamespace
+        WHERE nspname = 'validate_constraint'
+        AND contype = 'c'
+        ORDER BY 1,2
+      )
+      d $$)).RESULT :: json) :: json)).*
+    ORDER BY 1,2;
+
+CREATE VIEW constraint_validations AS
+  SELECT conname as "Constraint",
+         convalidated as "Validated?"
+  FROM pg_catalog.pg_constraint AS con
+         JOIN pg_catalog.pg_namespace AS ns ON ns.oid = con.connamespace
+  WHERE nspname = 'validate_constraint'
+    AND contype = 'c';
+
+CREATE TABLE referenced_table (id int UNIQUE, test_column int);
+SELECT create_reference_table('referenced_table');
+
+CREATE TABLE referencing_table (id int, ref_id int);
+SELECT create_distributed_table('referencing_table', 'ref_id');
+
+CREATE TABLE constrained_table (id int, constrained_column int);
+SELECT create_distributed_table('constrained_table', 'constrained_column');
+
+-- The two constraint types that are allowed to be NOT VALID
+BEGIN;
+ALTER TABLE constrained_table
+  ADD CONSTRAINT check_constraint CHECK (constrained_column > 100) NOT VALID;
+ALTER TABLE constrained_table
+  VALIDATE CONSTRAINT check_constraint;
+ROLLBACK;
+BEGIN;
+ALTER TABLE referencing_table
+  ADD CONSTRAINT fk_constraint FOREIGN KEY (ref_id) REFERENCES referenced_table (id) NOT VALID;
+ALTER TABLE referencing_table
+  VALIDATE CONSTRAINT fk_constraint;
+ROLLBACK;
+
+-- It is possible that some other table_constraint commands will support NOT VALID option in the future
+-- These should fail as Postgres does not yet allow these constraints to be NOT VALID
+-- If one of these queries are not failing on a future Postgres version, we will need to test corresponding VALIDATE CONSTRAINT queries
+ALTER TABLE constrained_table
+  ADD CONSTRAINT unique_constraint UNIQUE (constrained_column) NOT VALID;
+
+ALTER TABLE constrained_table
+  ADD CONSTRAINT pk_constraint PRIMARY KEY (id) NOT VALID;
+
+ALTER TABLE constrained_table
+  ADD CONSTRAINT exclude_constraint EXCLUDE USING gist (id WITH =, constrained_column WITH <>) NOT VALID;
+
+INSERT INTO constrained_table
+SELECT x, x
+from generate_series(1, 1000) as f (x);
+
+-- a constraint that can be validated
+ALTER TABLE constrained_table
+  ADD CONSTRAINT validatable_constraint CHECK (constrained_column < 10000) NOT VALID;
+ALTER TABLE constrained_table
+  VALIDATE CONSTRAINT validatable_constraint;
+
+-- Check which constraints are validated
+SELECT *
+FROM constraint_validations
+ORDER BY 1, 2;
+
+SELECT *
+FROM constraint_validations_in_workers
+ORDER BY 1, 2;
+
+DROP TABLE constrained_table;
+DROP TABLE referenced_table CASCADE;
+DROP TABLE referencing_table;
+
+DROP SCHEMA validate_constraint CASCADE;
+SET search_path TO DEFAULT;