diff --git a/src/backend/executor/execMain.c b/src/backend/executor/execMain.c
index de9aaf3f76..66cac46acf 100644
--- a/src/backend/executor/execMain.c
+++ b/src/backend/executor/execMain.c
@@ -1126,10 +1126,10 @@ CheckValidResultRel(ResultRelInfo *resultRelInfo, CmdType operation)
 
 			/*
 			 * Okay only if there's a suitable INSTEAD OF trigger.  Messages
-			 * here should match rewriteHandler.c's rewriteTargetView, except
-			 * that we omit errdetail because we haven't got the information
-			 * handy (and given that we really shouldn't get here anyway, it's
-			 * not worth great exertion to get).
+			 * here should match rewriteHandler.c's rewriteTargetView and
+			 * RewriteQuery, except that we omit errdetail because we haven't
+			 * got the information handy (and given that we really shouldn't
+			 * get here anyway, it's not worth great exertion to get).
 			 */
 			switch (operation)
 			{
diff --git a/src/backend/rewrite/rewriteHandler.c b/src/backend/rewrite/rewriteHandler.c
index 04b79fd1d0..ebb29e9aa3 100644
--- a/src/backend/rewrite/rewriteHandler.c
+++ b/src/backend/rewrite/rewriteHandler.c
@@ -3630,21 +3630,71 @@ RewriteQuery(Query *parsetree, List *rewrite_events)
 		}
 
 		/*
-		 * If there were no INSTEAD rules, and the target relation is a view
-		 * without any INSTEAD OF triggers, see if the view can be
+		 * If there was no unqualified INSTEAD rule, and the target relation
+		 * is a view without any INSTEAD OF triggers, see if the view can be
 		 * automatically updated.  If so, we perform the necessary query
 		 * transformation here and add the resulting query to the
 		 * product_queries list, so that it gets recursively rewritten if
 		 * necessary.
+		 *
+		 * If the view cannot be automatically updated, we throw an error here
+		 * which is OK since the query would fail at runtime anyway.  Throwing
+		 * the error here is preferable to the executor check since we have
+		 * more detailed information available about why the view isn't
+		 * updatable.
 		 */
-		if (!instead && qual_product == NULL &&
+		if (!instead &&
 			rt_entry_relation->rd_rel->relkind == RELKIND_VIEW &&
 			!view_has_instead_trigger(rt_entry_relation, event))
 		{
 			/*
+			 * If there were any qualified INSTEAD rules, don't allow the view
+			 * to be automatically updated (an unqualified INSTEAD rule or
+			 * INSTEAD OF trigger is required).
+			 *
+			 * The messages here should match execMain.c's CheckValidResultRel
+			 * and in principle make those checks in executor unnecessary, but
+			 * we keep them just in case.
+			 */
+			if (qual_product != NULL)
+			{
+				switch (parsetree->commandType)
+				{
+					case CMD_INSERT:
+						ereport(ERROR,
+								(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+								 errmsg("cannot insert into view \"%s\"",
+										RelationGetRelationName(rt_entry_relation)),
+								 errdetail("Views with conditional DO INSTEAD rules are not automatically updatable."),
+								 errhint("To enable inserting into the view, provide an INSTEAD OF INSERT trigger or an unconditional ON INSERT DO INSTEAD rule.")));
+						break;
+					case CMD_UPDATE:
+						ereport(ERROR,
+								(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+								 errmsg("cannot update view \"%s\"",
+										RelationGetRelationName(rt_entry_relation)),
+								 errdetail("Views with conditional DO INSTEAD rules are not automatically updatable."),
+								 errhint("To enable updating the view, provide an INSTEAD OF UPDATE trigger or an unconditional ON UPDATE DO INSTEAD rule.")));
+						break;
+					case CMD_DELETE:
+						ereport(ERROR,
+								(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+								 errmsg("cannot delete from view \"%s\"",
+										RelationGetRelationName(rt_entry_relation)),
+								 errdetail("Views with conditional DO INSTEAD rules are not automatically updatable."),
+								 errhint("To enable deleting from the view, provide an INSTEAD OF DELETE trigger or an unconditional ON DELETE DO INSTEAD rule.")));
+						break;
+					default:
+						elog(ERROR, "unrecognized CmdType: %d",
+							 (int) parsetree->commandType);
+						break;
+				}
+			}
+
+			/*
+			 * Attempt to rewrite the query to automatically update the view.
 			 * This throws an error if the view can't be automatically
-			 * updated, but that's OK since the query would fail at runtime
-			 * anyway.
+			 * updated.
 			 */
 			parsetree = rewriteTargetView(parsetree, rt_entry_relation);
 
diff --git a/src/test/regress/expected/updatable_views.out b/src/test/regress/expected/updatable_views.out
index 300a03bd70..f49c8d035b 100644
--- a/src/test/regress/expected/updatable_views.out
+++ b/src/test/regress/expected/updatable_views.out
@@ -328,6 +328,27 @@ UPDATE ro_view20 SET b=upper(b);
 ERROR:  cannot update view "ro_view20"
 DETAIL:  Views that return set-returning functions are not automatically updatable.
 HINT:  To enable updating the view, provide an INSTEAD OF UPDATE trigger or an unconditional ON UPDATE DO INSTEAD rule.
+-- A view with a conditional INSTEAD rule but no unconditional INSTEAD rules
+-- or INSTEAD OF triggers should be non-updatable and generate useful error
+-- messages with appropriate detail
+CREATE RULE rw_view16_ins_rule AS ON INSERT TO rw_view16
+  WHERE NEW.a > 0 DO INSTEAD INSERT INTO base_tbl VALUES (NEW.a, NEW.b);
+CREATE RULE rw_view16_upd_rule AS ON UPDATE TO rw_view16
+  WHERE OLD.a > 0 DO INSTEAD UPDATE base_tbl SET b=NEW.b WHERE a=OLD.a;
+CREATE RULE rw_view16_del_rule AS ON DELETE TO rw_view16
+  WHERE OLD.a > 0 DO INSTEAD DELETE FROM base_tbl WHERE a=OLD.a;
+INSERT INTO rw_view16 (a, b) VALUES (3, 'Row 3'); -- should fail
+ERROR:  cannot insert into view "rw_view16"
+DETAIL:  Views with conditional DO INSTEAD rules are not automatically updatable.
+HINT:  To enable inserting into the view, provide an INSTEAD OF INSERT trigger or an unconditional ON INSERT DO INSTEAD rule.
+UPDATE rw_view16 SET b='ROW 2' WHERE a=2; -- should fail
+ERROR:  cannot update view "rw_view16"
+DETAIL:  Views with conditional DO INSTEAD rules are not automatically updatable.
+HINT:  To enable updating the view, provide an INSTEAD OF UPDATE trigger or an unconditional ON UPDATE DO INSTEAD rule.
+DELETE FROM rw_view16 WHERE a=2; -- should fail
+ERROR:  cannot delete from view "rw_view16"
+DETAIL:  Views with conditional DO INSTEAD rules are not automatically updatable.
+HINT:  To enable deleting from the view, provide an INSTEAD OF DELETE trigger or an unconditional ON DELETE DO INSTEAD rule.
 DROP TABLE base_tbl CASCADE;
 NOTICE:  drop cascades to 16 other objects
 DETAIL:  drop cascades to view ro_view1
diff --git a/src/test/regress/sql/updatable_views.sql b/src/test/regress/sql/updatable_views.sql
index e928e86ca3..77a97191a9 100644
--- a/src/test/regress/sql/updatable_views.sql
+++ b/src/test/regress/sql/updatable_views.sql
@@ -98,6 +98,20 @@ DELETE FROM ro_view18;
 UPDATE ro_view19 SET last_value=1000;
 UPDATE ro_view20 SET b=upper(b);
 
+-- A view with a conditional INSTEAD rule but no unconditional INSTEAD rules
+-- or INSTEAD OF triggers should be non-updatable and generate useful error
+-- messages with appropriate detail
+CREATE RULE rw_view16_ins_rule AS ON INSERT TO rw_view16
+  WHERE NEW.a > 0 DO INSTEAD INSERT INTO base_tbl VALUES (NEW.a, NEW.b);
+CREATE RULE rw_view16_upd_rule AS ON UPDATE TO rw_view16
+  WHERE OLD.a > 0 DO INSTEAD UPDATE base_tbl SET b=NEW.b WHERE a=OLD.a;
+CREATE RULE rw_view16_del_rule AS ON DELETE TO rw_view16
+  WHERE OLD.a > 0 DO INSTEAD DELETE FROM base_tbl WHERE a=OLD.a;
+
+INSERT INTO rw_view16 (a, b) VALUES (3, 'Row 3'); -- should fail
+UPDATE rw_view16 SET b='ROW 2' WHERE a=2; -- should fail
+DELETE FROM rw_view16 WHERE a=2; -- should fail
+
 DROP TABLE base_tbl CASCADE;
 DROP VIEW ro_view10, ro_view12, ro_view18;
 DROP SEQUENCE uv_seq CASCADE;