Fix replica identity check for INSERT ON CONFLICT DO UPDATE.

If an INSERT has an ON CONFLICT DO UPDATE clause, the executor must
check that the target relation supports UPDATE as well as INSERT. In
particular, it must check that the target relation has a REPLICA
IDENTITY if it publishes updates. Formerly, it was not doing this
check, which could lead to silently breaking replication.

Fix by adding such a check to CheckValidResultRel(), which requires
adding a new onConflictAction argument. In back-branches, preserve ABI
compatibility by introducing a wrapper function with the original
signature.

Author: Zhijie Hou <houzj.fnst@fujitsu.com>
Reviewed-by: Ashutosh Bapat <ashutosh.bapat.oss@gmail.com>
Reviewed-by: Dean Rasheed <dean.a.rasheed@gmail.com>
Tested-by: Chao Li <li.evan.chao@gmail.com>
Discussion: https://postgr.es/m/OS3PR01MB57180C87E43A679A730482DF94B62@OS3PR01MB5718.jpnprd01.prod.outlook.com
Backpatch-through: 13

src/backend/executor/execMain.c

@@ -979,11 +979,15 @@ InitPlan(QueryDesc *queryDesc, int eflags)
  * Generally the parser and/or planner should have noticed any such mistake
  * already, but let's make sure.
  *
+ * For INSERT ON CONFLICT, the result relation is required to support the
+ * onConflictAction, regardless of whether a conflict actually occurs.
+ *
  * Note: when changing this function, you probably also need to look at
  * CheckValidRowMarkRel.
  */
 void
-CheckValidResultRel(ResultRelInfo *resultRelInfo, CmdType operation)
+CheckValidResultRelNew(ResultRelInfo *resultRelInfo, CmdType operation,
+					   OnConflictAction onConflictAction)
 {
 	Relation	resultRel = resultRelInfo->ri_RelationDesc;
 	TriggerDesc *trigDesc = resultRel->trigdesc;
@@ -998,6 +1002,13 @@ CheckValidResultRel(ResultRelInfo *resultRelInfo, CmdType operation)
 		case RELKIND_RELATION:
 		case RELKIND_PARTITIONED_TABLE:
 			CheckCmdReplicaIdentity(resultRel, operation);
+
+			/*
+			 * For INSERT ON CONFLICT DO UPDATE, additionally check that the
+			 * target relation supports UPDATE.
+			 */
+			if (onConflictAction == ONCONFLICT_UPDATE)
+				CheckCmdReplicaIdentity(resultRel, CMD_UPDATE);
 			break;
 		case RELKIND_SEQUENCE:
 			ereport(ERROR,
@@ -1116,6 +1127,16 @@ CheckValidResultRel(ResultRelInfo *resultRelInfo, CmdType operation)
 	}
 }
 
+/*
+ * ABI-compatible wrapper to emulate old version of the above function.
+ * Do not call this version in new code.
+ */
+void
+CheckValidResultRel(ResultRelInfo *resultRelInfo, CmdType operation)
+{
+	return CheckValidResultRelNew(resultRelInfo, operation, ONCONFLICT_NONE);
+}
+
 /*
  * Check that a proposed rowmark target relation is a legal target
  *

src/backend/executor/execPartition.c

@@ -352,8 +352,11 @@ ExecFindPartition(ModifyTableState *mtstate,
 											   true, false);
 				if (rri)
 				{
+					ModifyTable *node = (ModifyTable *) mtstate->ps.plan;
+
 					/* Verify this ResultRelInfo allows INSERTs */
-					CheckValidResultRel(rri, CMD_INSERT);
+					CheckValidResultRelNew(rri, CMD_INSERT,
+										   node ? node->onConflictAction : ONCONFLICT_NONE);
 
 					/*
 					 * Initialize information needed to insert this and
@@ -519,7 +522,8 @@ ExecInitPartitionInfo(ModifyTableState *mtstate, EState *estate,
 	 * partition-key becomes a DELETE+INSERT operation, so this check is still
 	 * required when the operation is CMD_UPDATE.
 	 */
-	CheckValidResultRel(leaf_part_rri, CMD_INSERT);
+	CheckValidResultRelNew(leaf_part_rri, CMD_INSERT,
+						   node ? node->onConflictAction : ONCONFLICT_NONE);
 
 	/*
 	 * Open partition indices.  The user may have asked to check for conflicts

src/backend/executor/nodeModifyTable.c

@@ -2984,7 +2984,8 @@ ExecInitModifyTable(ModifyTable *node, EState *estate, int eflags)
 		/*
 		 * Verify result relation is a valid target for the current operation
 		 */
-		CheckValidResultRel(resultRelInfo, operation);
+		CheckValidResultRelNew(resultRelInfo, operation,
+							   node->onConflictAction);
 
 		resultRelInfo++;
 		i++;

src/include/executor/executor.h

@@ -198,6 +198,8 @@ extern void standard_ExecutorEnd(QueryDesc *queryDesc);
 extern void ExecutorRewind(QueryDesc *queryDesc);
 extern bool ExecCheckRTPerms(List *rangeTable, bool ereport_on_violation);
 extern bool ExecCheckRTEPerms(RangeTblEntry *rte);
+extern void CheckValidResultRelNew(ResultRelInfo *resultRelInfo, CmdType operation,
+								   OnConflictAction onConflictAction);
 extern void CheckValidResultRel(ResultRelInfo *resultRelInfo, CmdType operation);
 extern void InitResultRelInfo(ResultRelInfo *resultRelInfo,
 							  Relation resultRelationDesc,

src/test/regress/expected/publication.out

@@ -341,6 +341,29 @@ DROP PUBLICATION testpib_ins_trunct;
 DROP PUBLICATION testpub_fortbl;
 DROP SCHEMA pub_test CASCADE;
 NOTICE:  drop cascades to table pub_test.testpub_nopk
+-- Test that the INSERT ON CONFLICT command correctly checks REPLICA IDENTITY
+-- when the target table is published.
+CREATE TABLE testpub_insert_onconfl_no_ri (a int unique, b int);
+CREATE TABLE testpub_insert_onconfl_parted (a int unique, b int) PARTITION by RANGE (a);
+CREATE TABLE testpub_insert_onconfl_part_no_ri PARTITION OF testpub_insert_onconfl_parted FOR VALUES FROM (1) TO (10);
+SET client_min_messages = 'ERROR';
+CREATE PUBLICATION pub1 FOR ALL TABLES;
+RESET client_min_messages;
+-- fail - missing REPLICA IDENTITY
+INSERT INTO testpub_insert_onconfl_no_ri VALUES (1, 1) ON CONFLICT (a) DO UPDATE SET b = 2;
+ERROR:  cannot update table "testpub_insert_onconfl_no_ri" because it does not have a replica identity and publishes updates
+HINT:  To enable updating the table, set REPLICA IDENTITY using ALTER TABLE.
+-- ok - no updates
+INSERT INTO testpub_insert_onconfl_no_ri VALUES (1, 1) ON CONFLICT DO NOTHING;
+-- fail - missing REPLICA IDENTITY in partition testpub_insert_onconfl_no_ri
+INSERT INTO testpub_insert_onconfl_parted VALUES (1, 1) ON CONFLICT (a) DO UPDATE SET b = 2;
+ERROR:  cannot update table "testpub_insert_onconfl_part_no_ri" because it does not have a replica identity and publishes updates
+HINT:  To enable updating the table, set REPLICA IDENTITY using ALTER TABLE.
+-- ok - no updates
+INSERT INTO testpub_insert_onconfl_parted VALUES (1, 1) ON CONFLICT DO NOTHING;
+DROP PUBLICATION pub1;
+DROP TABLE testpub_insert_onconfl_no_ri;
+DROP TABLE testpub_insert_onconfl_parted;
 RESET SESSION AUTHORIZATION;
 DROP ROLE regress_publication_user, regress_publication_user2;
 DROP ROLE regress_publication_user_dummy;

src/test/regress/sql/publication.sql

@@ -215,6 +215,32 @@ DROP PUBLICATION testpub_fortbl;
 
 DROP SCHEMA pub_test CASCADE;
 
+-- Test that the INSERT ON CONFLICT command correctly checks REPLICA IDENTITY
+-- when the target table is published.
+CREATE TABLE testpub_insert_onconfl_no_ri (a int unique, b int);
+CREATE TABLE testpub_insert_onconfl_parted (a int unique, b int) PARTITION by RANGE (a);
+CREATE TABLE testpub_insert_onconfl_part_no_ri PARTITION OF testpub_insert_onconfl_parted FOR VALUES FROM (1) TO (10);
+
+SET client_min_messages = 'ERROR';
+CREATE PUBLICATION pub1 FOR ALL TABLES;
+RESET client_min_messages;
+
+-- fail - missing REPLICA IDENTITY
+INSERT INTO testpub_insert_onconfl_no_ri VALUES (1, 1) ON CONFLICT (a) DO UPDATE SET b = 2;
+
+-- ok - no updates
+INSERT INTO testpub_insert_onconfl_no_ri VALUES (1, 1) ON CONFLICT DO NOTHING;
+
+-- fail - missing REPLICA IDENTITY in partition testpub_insert_onconfl_no_ri
+INSERT INTO testpub_insert_onconfl_parted VALUES (1, 1) ON CONFLICT (a) DO UPDATE SET b = 2;
+
+-- ok - no updates
+INSERT INTO testpub_insert_onconfl_parted VALUES (1, 1) ON CONFLICT DO NOTHING;
+
+DROP PUBLICATION pub1;
+DROP TABLE testpub_insert_onconfl_no_ri;
+DROP TABLE testpub_insert_onconfl_parted;
+
 RESET SESSION AUTHORIZATION;
 DROP ROLE regress_publication_user, regress_publication_user2;
 DROP ROLE regress_publication_user_dummy;