2 files changed, 7 insertions, 207 deletions

diff --git a/src/backend/rewrite/rewriteHandler.c b/src/backend/rewrite/rewriteHandler.c
index 98239f569ae..88140bc6877 100644
--- a/src/backend/rewrite/rewriteHandler.c
+++ b/src/backend/rewrite/rewriteHandler.c
@@ -1377,57 +1377,6 @@ rewriteTargetListUD(Query *parsetree, RangeTblEntry *target_rte,
 	}
 }
 
-void
-rewriteTargetListMerge(Query *parsetree, Relation target_relation)
-{
-	Var		   *var = NULL;
-	const char *attrname;
-	TargetEntry *tle;
-
-	Assert(target_relation->rd_rel->relkind == RELKIND_RELATION ||
-		   target_relation->rd_rel->relkind == RELKIND_MATVIEW ||
-		   target_relation->rd_rel->relkind == RELKIND_PARTITIONED_TABLE);
-
-	/*
-	 * Emit CTID so that executor can find the row to update or delete.
-	 */
-	var = makeVar(parsetree->mergeTarget_relation,
-				  SelfItemPointerAttributeNumber,
-				  TIDOID,
-				  -1,
-				  InvalidOid,
-				  0);
-
-	attrname = "ctid";
-	tle = makeTargetEntry((Expr *) var,
-						  list_length(parsetree->targetList) + 1,
-						  pstrdup(attrname),
-						  true);
-
-	parsetree->targetList = lappend(parsetree->targetList, tle);
-
-	/*
-	 * If we are dealing with partitioned table, then emit TABLEOID so that
-	 * executor can find the partition the row belongs to.
-	 */
-	if (target_relation->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
-	{
-		var = makeVar(parsetree->mergeTarget_relation,
-				TableOidAttributeNumber,
-				OIDOID,
-				-1,
-				InvalidOid,
-				0);
-
-		attrname = "tableoid";
-		tle = makeTargetEntry((Expr *) var,
-				list_length(parsetree->targetList) + 1,
-				pstrdup(attrname),
-				true);
-
-		parsetree->targetList = lappend(parsetree->targetList, tle);
-	}
-}
 
 /*
  * matchLocks -
@@ -3382,7 +3331,6 @@ RewriteQuery(Query *parsetree, List *rewrite_events)
 		}
 		else if (event == CMD_UPDATE)
 		{
-			Assert(parsetree->override == OVERRIDING_NOT_SET);
 			parsetree->targetList =
 				rewriteTargetListIU(parsetree->targetList,
 									parsetree->commandType,
@@ -3390,50 +3338,6 @@ RewriteQuery(Query *parsetree, List *rewrite_events)
 									rt_entry_relation,
 									parsetree->resultRelation, NULL);
 		}
-		else if (event == CMD_MERGE)
-		{
-			Assert(parsetree->override == OVERRIDING_NOT_SET);
-
-			/*
-			 * Rewrite each action targetlist separately
-			 */
-			foreach(lc1, parsetree->mergeActionList)
-			{
-				MergeAction *action = (MergeAction *) lfirst(lc1);
-
-				switch (action->commandType)
-				{
-					case CMD_NOTHING:
-					case CMD_DELETE:	/* Nothing to do here */
-						break;
-					case CMD_UPDATE:
-						action->targetList =
-							rewriteTargetListIU(action->targetList,
-												action->commandType,
-												parsetree->override,
-												rt_entry_relation,
-												parsetree->resultRelation,
-												NULL);
-						break;
-					case CMD_INSERT:
-						{
-							InsertStmt *istmt = (InsertStmt *) action->stmt;
-
-							action->targetList =
-								rewriteTargetListIU(action->targetList,
-													action->commandType,
-													istmt->override,
-													rt_entry_relation,
-													parsetree->resultRelation,
-													NULL);
-						}
-						break;
-					default:
-						elog(ERROR, "unrecognized commandType: %d", action->commandType);
-						break;
-				}
-			}
-		}
 		else if (event == CMD_DELETE)
 		{
 			/* Nothing to do here */
@@ -3447,20 +3351,13 @@ RewriteQuery(Query *parsetree, List *rewrite_events)
 		locks = matchLocks(event, rt_entry_relation->rd_rules,
 						   result_relation, parsetree, &hasUpdate);
 
-		/*
-		 * XXX MERGE doesn't support write rules because they would violate
-		 * the SQL Standard spec and would be unclear how they should work.
-		 */
-		if (event == CMD_MERGE)
-			product_queries = NIL;
-		else
-			product_queries = fireRules(parsetree,
-										result_relation,
-										event,
-										locks,
-										&instead,
-										&returning,
-										&qual_product);
+		product_queries = fireRules(parsetree,
+									result_relation,
+									event,
+									locks,
+									&instead,
+									&returning,
+									&qual_product);
 
 		/*
 		 * If there were no INSTEAD rules, and the target relation is a view
diff --git a/src/backend/rewrite/rowsecurity.c b/src/backend/rewrite/rowsecurity.c
index 6e85886e646..ce77a18bc96 100644
--- a/src/backend/rewrite/rowsecurity.c
+++ b/src/backend/rewrite/rowsecurity.c
@@ -379,95 +379,6 @@ get_row_security_policies(Query *root, RangeTblEntry *rte, int rt_index,
 		}
 	}
 
-	/*
-	 * FOR MERGE, we fetch policies for UPDATE, DELETE and INSERT (and ALL)
-	 * and set them up so that we can enforce the appropriate policy depending
-	 * on the final action we take.
-	 *
-	 * We don't fetch the SELECT policies since they are correctly applied to
-	 * the root->mergeTarget_relation. The target rows are selected after
-	 * joining the mergeTarget_relation and the source relation and hence it's
-	 * enough to apply SELECT policies to the mergeTarget_relation.
-	 *
-	 * We don't push the UPDATE/DELETE USING quals to the RTE because we don't
-	 * really want to apply them while scanning the relation since we don't
-	 * know whether we will be doing a UPDATE or a DELETE at the end. We apply
-	 * the respective policy once we decide the final action on the target
-	 * tuple.
-	 *
-	 * XXX We are setting up USING quals as WITH CHECK. If RLS prohibits
-	 * UPDATE/DELETE on the target row, we shall throw an error instead of
-	 * silently ignoring the row. This is different than how normal
-	 * UPDATE/DELETE works and more in line with INSERT ON CONFLICT DO UPDATE
-	 * handling.
-	 */
-	if (commandType == CMD_MERGE)
-	{
-		List	   *merge_permissive_policies;
-		List	   *merge_restrictive_policies;
-
-		/*
-		 * Fetch the UPDATE policies and set them up to execute on the
-		 * existing target row before doing UPDATE.
-		 */
-		get_policies_for_relation(rel, CMD_UPDATE, user_id,
-								  &merge_permissive_policies,
-								  &merge_restrictive_policies);
-
-		/*
-		 * WCO_RLS_MERGE_UPDATE_CHECK is used to check UPDATE USING quals on
-		 * the existing target row.
-		 */
-		add_with_check_options(rel, rt_index,
-							   WCO_RLS_MERGE_UPDATE_CHECK,
-							   merge_permissive_policies,
-							   merge_restrictive_policies,
-							   withCheckOptions,
-							   hasSubLinks,
-							   true);
-
-		/*
-		 * Same with DELETE policies.
-		 */
-		get_policies_for_relation(rel, CMD_DELETE, user_id,
-								  &merge_permissive_policies,
-								  &merge_restrictive_policies);
-
-		add_with_check_options(rel, rt_index,
-							   WCO_RLS_MERGE_DELETE_CHECK,
-							   merge_permissive_policies,
-							   merge_restrictive_policies,
-							   withCheckOptions,
-							   hasSubLinks,
-							   true);
-
-		/*
-		 * No special handling is required for INSERT policies. They will be
-		 * checked and enforced during ExecInsert(). But we must add them to
-		 * withCheckOptions.
-		 */
-		get_policies_for_relation(rel, CMD_INSERT, user_id,
-								  &merge_permissive_policies,
-								  &merge_restrictive_policies);
-
-		add_with_check_options(rel, rt_index,
-							   WCO_RLS_INSERT_CHECK,
-							   merge_permissive_policies,
-							   merge_restrictive_policies,
-							   withCheckOptions,
-							   hasSubLinks,
-							   false);
-
-		/* Enforce the WITH CHECK clauses of the UPDATE policies */
-		add_with_check_options(rel, rt_index,
-							   WCO_RLS_UPDATE_CHECK,
-							   merge_permissive_policies,
-							   merge_restrictive_policies,
-							   withCheckOptions,
-							   hasSubLinks,
-							   false);
-	}
-
 	heap_close(rel, NoLock);
 
 	/*
@@ -527,14 +438,6 @@ get_policies_for_relation(Relation relation, CmdType cmd, Oid user_id,
 					if (policy->polcmd == ACL_DELETE_CHR)
 						cmd_matches = true;
 					break;
-				case CMD_MERGE:
-
-					/*
-					 * We do not support a separate policy for MERGE command.
-					 * Instead it derives from the policies defined for other
-					 * commands.
-					 */
-					break;
 				default:
 					elog(ERROR, "unrecognized policy command type %d",
 						 (int) cmd);