diff --git a/contrib/postgres_fdw/expected/postgres_fdw.out b/contrib/postgres_fdw/expected/postgres_fdw.out index 30e95f585f..5f74595198 100644 --- a/contrib/postgres_fdw/expected/postgres_fdw.out +++ b/contrib/postgres_fdw/expected/postgres_fdw.out @@ -10706,6 +10706,72 @@ SELECT * FROM result_tbl ORDER BY a; (12 rows) DELETE FROM result_tbl; +-- Prevent async execution if we use gating Result nodes for pseudoconstant +-- quals +EXPLAIN (VERBOSE, COSTS OFF) +SELECT * FROM async_pt WHERE CURRENT_USER = SESSION_USER; + QUERY PLAN +---------------------------------------------------------------- + Append + -> Result + Output: async_pt_1.a, async_pt_1.b, async_pt_1.c + One-Time Filter: (CURRENT_USER = SESSION_USER) + -> Foreign Scan on public.async_p1 async_pt_1 + Output: async_pt_1.a, async_pt_1.b, async_pt_1.c + Remote SQL: SELECT a, b, c FROM public.base_tbl1 + -> Result + Output: async_pt_2.a, async_pt_2.b, async_pt_2.c + One-Time Filter: (CURRENT_USER = SESSION_USER) + -> Foreign Scan on public.async_p2 async_pt_2 + Output: async_pt_2.a, async_pt_2.b, async_pt_2.c + Remote SQL: SELECT a, b, c FROM public.base_tbl2 + -> Result + Output: async_pt_3.a, async_pt_3.b, async_pt_3.c + One-Time Filter: (CURRENT_USER = SESSION_USER) + -> Seq Scan on public.async_p3 async_pt_3 + Output: async_pt_3.a, async_pt_3.b, async_pt_3.c +(18 rows) + +EXPLAIN (VERBOSE, COSTS OFF) +(SELECT * FROM async_p1 WHERE CURRENT_USER = SESSION_USER) +UNION ALL +(SELECT * FROM async_p2 WHERE CURRENT_USER = SESSION_USER); + QUERY PLAN +---------------------------------------------------------------- + Append + -> Result + Output: async_p1.a, async_p1.b, async_p1.c + One-Time Filter: (CURRENT_USER = SESSION_USER) + -> Foreign Scan on public.async_p1 + Output: async_p1.a, async_p1.b, async_p1.c + Remote SQL: SELECT a, b, c FROM public.base_tbl1 + -> Result + Output: async_p2.a, async_p2.b, async_p2.c + One-Time Filter: (CURRENT_USER = SESSION_USER) + -> Foreign Scan on public.async_p2 + Output: async_p2.a, async_p2.b, async_p2.c + Remote SQL: SELECT a, b, c FROM public.base_tbl2 +(13 rows) + +EXPLAIN (VERBOSE, COSTS OFF) +SELECT * FROM ((SELECT * FROM async_p1 WHERE b < 10) UNION ALL (SELECT * FROM async_p2 WHERE b < 10)) s WHERE CURRENT_USER = SESSION_USER; + QUERY PLAN +--------------------------------------------------------------------------------- + Append + -> Result + Output: async_p1.a, async_p1.b, async_p1.c + One-Time Filter: (CURRENT_USER = SESSION_USER) + -> Foreign Scan on public.async_p1 + Output: async_p1.a, async_p1.b, async_p1.c + Remote SQL: SELECT a, b, c FROM public.base_tbl1 WHERE ((b < 10)) + -> Result + Output: async_p2.a, async_p2.b, async_p2.c + One-Time Filter: (CURRENT_USER = SESSION_USER) + -> Foreign Scan on public.async_p2 + Output: async_p2.a, async_p2.b, async_p2.c + Remote SQL: SELECT a, b, c FROM public.base_tbl2 WHERE ((b < 10)) +(13 rows) + -- Test that pending requests are processed properly SET enable_mergejoin TO false; SET enable_hashjoin TO false; diff --git a/contrib/postgres_fdw/sql/postgres_fdw.sql b/contrib/postgres_fdw/sql/postgres_fdw.sql index ea35e61eb8..e1b93f39f1 100644 --- a/contrib/postgres_fdw/sql/postgres_fdw.sql +++ b/contrib/postgres_fdw/sql/postgres_fdw.sql @@ -3398,6 +3398,19 @@ UNION ALL SELECT * FROM result_tbl ORDER BY a; DELETE FROM result_tbl; +-- Prevent async execution if we use gating Result nodes for pseudoconstant +-- quals +EXPLAIN (VERBOSE, COSTS OFF) +SELECT * FROM async_pt WHERE CURRENT_USER = SESSION_USER; + +EXPLAIN (VERBOSE, COSTS OFF) +(SELECT * FROM async_p1 WHERE CURRENT_USER = SESSION_USER) +UNION ALL +(SELECT * FROM async_p2 WHERE CURRENT_USER = SESSION_USER); + +EXPLAIN (VERBOSE, COSTS OFF) +SELECT * FROM ((SELECT * FROM async_p1 WHERE b < 10) UNION ALL (SELECT * FROM async_p2 WHERE b < 10)) s WHERE CURRENT_USER = SESSION_USER; + -- Test that pending requests are processed properly SET enable_mergejoin TO false; SET enable_hashjoin TO false; diff --git a/src/backend/optimizer/plan/createplan.c b/src/backend/optimizer/plan/createplan.c index 95476ada0b..447d908c8a 100644 --- a/src/backend/optimizer/plan/createplan.c +++ b/src/backend/optimizer/plan/createplan.c @@ -1125,6 +1125,13 @@ mark_async_capable_plan(Plan *plan, Path *path) { SubqueryScan *scan_plan = (SubqueryScan *) plan; + /* + * If the generated plan node includes a gating Result node, + * we can't execute it asynchronously. + */ + if (IsA(plan, Result)) + return false; + /* * If a SubqueryScan node atop of an async-capable plan node * is deletable, consider it as async-capable. @@ -1139,6 +1146,13 @@ mark_async_capable_plan(Plan *plan, Path *path) { FdwRoutine *fdwroutine = path->parent->fdwroutine; + /* + * If the generated plan node includes a gating Result node, + * we can't execute it asynchronously. + */ + if (IsA(plan, Result)) + return false; + Assert(fdwroutine != NULL); if (fdwroutine->IsForeignPathAsyncCapable != NULL && fdwroutine->IsForeignPathAsyncCapable((ForeignPath *) path))