Clarify error message for local and distributed query plans.

src/backend/distributed/planner/multi_logical_planner.c

@@ -2682,11 +2682,10 @@ NeedsDistributedPlanning(Query *queryTree)
 		}
 	}
 
-	/* users can't mix local and distributed relations in one query */
 	if (hasLocalRelation && hasDistributedRelation)
 	{
-		ereport(ERROR, (errmsg("cannot plan queries that include both regular and "
-							   "partitioned relations")));
+		ereport(ERROR, (errmsg("cannot plan queries which include both local and "
+							   "distributed relations")));
 	}
 
 	return hasDistributedRelation;

src/test/regress/expected/multi_modifications.out

@@ -264,7 +264,7 @@ CREATE TABLE bidders ( name text, id bigint );
 DELETE FROM limit_orders USING bidders WHERE limit_orders.id = 246 AND
 											 limit_orders.bidder_id = bidders.id AND
 											 bidders.name = 'Bernie Madoff';
-ERROR:  cannot plan queries that include both regular and partitioned relations
+ERROR:  cannot plan queries which include both local and distributed relations
 -- commands containing a CTE are unsupported
 WITH deleted_orders AS (INSERT INTO limit_orders DEFAULT VALUES RETURNING *)
 DELETE FROM limit_orders;
@@ -407,7 +407,7 @@ UPDATE limit_orders SET limit_price = 0.00 FROM bidders
 					WHERE limit_orders.id = 246 AND
 						  limit_orders.bidder_id = bidders.id AND
 						  bidders.name = 'Bernie Madoff';
-ERROR:  cannot plan queries that include both regular and partitioned relations
+ERROR:  cannot plan queries which include both local and distributed relations
 -- commands containing a CTE are unsupported
 WITH deleted_orders AS (INSERT INTO limit_orders DEFAULT VALUES RETURNING *)
 UPDATE limit_orders SET symbol = 'GM';

src/test/regress/expected/multi_mx_modifications.out

@@ -170,7 +170,7 @@ CREATE TABLE bidders ( name text, id bigint );
 DELETE FROM limit_orders_mx USING bidders WHERE limit_orders_mx.id = 246 AND
 											 limit_orders_mx.bidder_id = bidders.id AND
 											 bidders.name = 'Bernie Madoff';
-ERROR:  cannot plan queries that include both regular and partitioned relations
+ERROR:  cannot plan queries which include both local and distributed relations
 -- commands containing a CTE are unsupported
 WITH deleted_orders AS (INSERT INTO limit_orders_mx DEFAULT VALUES RETURNING *)
 DELETE FROM limit_orders_mx;
@@ -243,7 +243,7 @@ UPDATE limit_orders_mx SET limit_price = 0.00 FROM bidders
 					WHERE limit_orders_mx.id = 246 AND
 						  limit_orders_mx.bidder_id = bidders.id AND
 						  bidders.name = 'Bernie Madoff';
-ERROR:  cannot plan queries that include both regular and partitioned relations
+ERROR:  cannot plan queries which include both local and distributed relations
 -- commands containing a CTE are unsupported
 WITH deleted_orders AS (INSERT INTO limit_orders_mx DEFAULT VALUES RETURNING *)
 UPDATE limit_orders_mx SET symbol = 'GM';

src/test/regress/expected/multi_simple_queries.out

@@ -178,14 +178,14 @@ HINT:  Consider using an equality filter on the distributed table's partition co
 -- queries using CTEs are unsupported
 WITH long_names AS ( SELECT id FROM authors WHERE char_length(name) > 15 )
 SELECT title FROM articles;
-ERROR:  cannot plan queries that include both regular and partitioned relations
+ERROR:  cannot plan queries which include both local and distributed relations
 -- queries which involve functions in FROM clause are unsupported.
 SELECT * FROM articles, position('om' in 'Thomas');
 ERROR:  could not run distributed query with complex table expressions
 HINT:  Consider using an equality filter on the distributed table's partition column.
 -- subqueries are not supported in WHERE clause in Citus
 SELECT * FROM articles WHERE author_id IN (SELECT id FROM authors WHERE name LIKE '%a');
-ERROR:  cannot plan queries that include both regular and partitioned relations
+ERROR:  cannot plan queries which include both local and distributed relations
 -- subqueries are supported in FROM clause
 SELECT articles.id,test.word_count
 FROM articles, (SELECT id, word_count FROM articles) AS test WHERE test.id = articles.id
@@ -251,10 +251,10 @@ ERROR:  could not run distributed query with subquery outside the FROM and WHERE
 HINT:  Consider using an equality filter on the distributed table's partition column.
 -- joins are not supported between local and distributed tables
 SELECT title, authors.name FROM authors, articles WHERE authors.id = articles.author_id;
-ERROR:  cannot plan queries that include both regular and partitioned relations
+ERROR:  cannot plan queries which include both local and distributed relations
 -- inner joins are not supported (I think)
 SELECT * FROM  (articles INNER JOIN authors ON articles.id = authors.id);
-ERROR:  cannot plan queries that include both regular and partitioned relations
+ERROR:  cannot plan queries which include both local and distributed relations
 -- test use of EXECUTE statements within plpgsql
 DO $sharded_execute$
 	BEGIN