Merge pull request #3816 from citusdata/fix_false_subquery

Remove assertion for subqueries in WHERE clause  ANDed with FALSE

src/backend/distributed/planner/query_colocation_checker.c

@@ -191,12 +191,16 @@ SubqueryColocated(Query *subquery, ColocatedJoinChecker *checker)
 	/*
 	 * There are no relations in the input subquery, such as a subquery
 	 * that consist of only intermediate results or without FROM
-	 * clause.
+	 * clause or subquery in WHERE clause anded with FALSE.
+	 *
+	 * Note that for the subquery in WHERE clause, the input original
+	 * subquery (a.k.a., which didn't go through standard_planner()) may
+	 * contain distributed relations, but postgres is smart enough to
+	 * not generate the restriction information. That's the reason for
+	 * not asserting non-existence of distributed relations.
 	 */
 	if (list_length(filteredRestrictionList) == 0)
 	{
-		Assert(!FindNodeCheck((Node *) subquery, IsDistributedTableRTE));
-
 		return true;
 	}
 

src/test/regress/expected/subquery_in_where.out

@@ -634,6 +634,64 @@ DEBUG:  Plan XXX query after replacing subqueries and CTEs: SELECT generate_seri
                3
 (3 rows)
 
+-- non-colocated subquery in WHERE clause ANDed with false
+SELECT count(*)
+FROM users_Table
+WHERE (FALSE AND EXISTS (SELECT * FROM events_table));
+ count
+---------------------------------------------------------------------
+     0
+(1 row)
+
+-- multiple non-colocated subqueries in WHERE clause ANDed with false
+SELECT count(*)
+FROM users_Table
+WHERE value_1 IN
+    (SELECT value_1
+     FROM users_Table) OR (FALSE AND EXISTS (SELECT * FROM events_table));
+DEBUG:  generating subplan XXX_1 for subquery SELECT value_1 FROM public.users_table
+DEBUG:  Plan XXX query after replacing subqueries and CTEs: SELECT count(*) AS count FROM public.users_table WHERE ((value_1 OPERATOR(pg_catalog.=) ANY (SELECT intermediate_result.value_1 FROM read_intermediate_result('XXX_1'::text, 'binary'::citus_copy_format) intermediate_result(value_1 integer))) OR (false AND (EXISTS (SELECT events_table.user_id, events_table."time", events_table.event_type, events_table.value_2, events_table.value_3, events_table.value_4 FROM public.events_table))))
+ count
+---------------------------------------------------------------------
+   101
+(1 row)
+
+-- multiple non-colocated subqueries in WHERE clause ANDed with false
+SELECT count(*)
+FROM users_Table
+WHERE value_1 IN
+    (SELECT value_1
+     FROM users_Table) AND (FALSE AND EXISTS (SELECT * FROM events_table));
+ count
+---------------------------------------------------------------------
+     0
+(1 row)
+
+-- non-colocated subquery in WHERE clause ANDed with true
+SELECT count(*)
+FROM users_Table
+WHERE (TRUE AND EXISTS (SELECT * FROM events_table));
+DEBUG:  generating subplan XXX_1 for subquery SELECT user_id, "time", event_type, value_2, value_3, value_4 FROM public.events_table
+DEBUG:  Plan XXX query after replacing subqueries and CTEs: SELECT count(*) AS count FROM public.users_table WHERE (true AND (EXISTS (SELECT intermediate_result.user_id, intermediate_result."time", intermediate_result.event_type, intermediate_result.value_2, intermediate_result.value_3, intermediate_result.value_4 FROM read_intermediate_result('XXX_1'::text, 'binary'::citus_copy_format) intermediate_result(user_id integer, "time" timestamp without time zone, event_type integer, value_2 integer, value_3 double precision, value_4 bigint))))
+ count
+---------------------------------------------------------------------
+   101
+(1 row)
+
+-- multiple non-colocated subqueries in WHERE clause ANDed with true
+SELECT count(*)
+FROM users_Table
+WHERE value_1 IN
+    (SELECT value_1
+     FROM users_Table) OR (EXISTS (SELECT * FROM events_table));
+DEBUG:  generating subplan XXX_1 for subquery SELECT value_1 FROM public.users_table
+DEBUG:  generating subplan XXX_2 for subquery SELECT user_id, "time", event_type, value_2, value_3, value_4 FROM public.events_table
+DEBUG:  Plan XXX query after replacing subqueries and CTEs: SELECT count(*) AS count FROM public.users_table WHERE ((value_1 OPERATOR(pg_catalog.=) ANY (SELECT intermediate_result.value_1 FROM read_intermediate_result('XXX_1'::text, 'binary'::citus_copy_format) intermediate_result(value_1 integer))) OR (EXISTS (SELECT intermediate_result.user_id, intermediate_result."time", intermediate_result.event_type, intermediate_result.value_2, intermediate_result.value_3, intermediate_result.value_4 FROM read_intermediate_result('XXX_2'::text, 'binary'::citus_copy_format) intermediate_result(user_id integer, "time" timestamp without time zone, event_type integer, value_2 integer, value_3 double precision, value_4 bigint))))
+ count
+---------------------------------------------------------------------
+   101
+(1 row)
+
 -- Local tables also planned recursively, so using it as part of the FROM clause
 -- make the clause recurring
 CREATE TABLE local_table(id int, value_1 int);

src/test/regress/sql/subquery_in_where.sql

@@ -471,6 +471,37 @@ IN
 ORDER BY
 	generate_series ASC;
 
+-- non-colocated subquery in WHERE clause ANDed with false
+SELECT count(*)
+FROM users_Table
+WHERE (FALSE AND EXISTS (SELECT * FROM events_table));
+
+-- multiple non-colocated subqueries in WHERE clause ANDed with false
+SELECT count(*)
+FROM users_Table
+WHERE value_1 IN
+    (SELECT value_1
+     FROM users_Table) OR (FALSE AND EXISTS (SELECT * FROM events_table));
+
+-- multiple non-colocated subqueries in WHERE clause ANDed with false
+SELECT count(*)
+FROM users_Table
+WHERE value_1 IN
+    (SELECT value_1
+     FROM users_Table) AND (FALSE AND EXISTS (SELECT * FROM events_table));
+
+-- non-colocated subquery in WHERE clause ANDed with true
+SELECT count(*)
+FROM users_Table
+WHERE (TRUE AND EXISTS (SELECT * FROM events_table));
+
+-- multiple non-colocated subqueries in WHERE clause ANDed with true
+SELECT count(*)
+FROM users_Table
+WHERE value_1 IN
+    (SELECT value_1
+     FROM users_Table) OR (EXISTS (SELECT * FROM events_table));
+
 -- Local tables also planned recursively, so using it as part of the FROM clause
 -- make the clause recurring
 CREATE TABLE local_table(id int, value_1 int);