From 7b19b80a7f231e46184e378d76b3157f0e856b4d Mon Sep 17 00:00:00 2001 From: Alexander Pyhalov Date: Tue, 3 Nov 2026 16:31:37 +0300 Subject: [PATCH] Make Append subplans async capable in more cases --- .../postgres_fdw/expected/postgres_fdw.out | 38 +++++++++++++++++++ contrib/postgres_fdw/sql/postgres_fdw.sql | 4 ++ src/backend/optimizer/plan/createplan.c | 6 ++- 3 files changed, 46 insertions(+), 2 deletions(-) diff --git a/contrib/postgres_fdw/expected/postgres_fdw.out b/contrib/postgres_fdw/expected/postgres_fdw.out index cb0c525bd2d..a23ddf3f3d8 100644 --- a/contrib/postgres_fdw/expected/postgres_fdw.out +++ b/contrib/postgres_fdw/expected/postgres_fdw.out @@ -12365,6 +12365,44 @@ SELECT * FROM result_tbl ORDER BY a; (2 rows) DELETE FROM result_tbl; +EXPLAIN (VERBOSE, COSTS OFF) +SELECT * FROM async_pt WHERE b % 100 = 0 ORDER BY a; + QUERY PLAN +------------------------------------------------------------------------------------------------------------ + Append + -> Async 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 WHERE (((b % 100) = 0)) ORDER BY a ASC NULLS LAST + -> Async 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 WHERE (((b % 100) = 0)) ORDER BY a ASC NULLS LAST +(7 rows) + +SELECT * FROM async_pt WHERE b % 100 = 0 ORDER BY a; + a | b | c +------+-----+------ + 1000 | 0 | 0000 + 1100 | 100 | 0100 + 1200 | 200 | 0200 + 1300 | 300 | 0300 + 1400 | 400 | 0400 + 1500 | 500 | 0500 + 1600 | 600 | 0600 + 1700 | 700 | 0700 + 1800 | 800 | 0800 + 1900 | 900 | 0900 + 2000 | 0 | 0000 + 2100 | 100 | 0100 + 2200 | 200 | 0200 + 2300 | 300 | 0300 + 2400 | 400 | 0400 + 2500 | 500 | 0500 + 2600 | 600 | 0600 + 2700 | 700 | 0700 + 2800 | 800 | 0800 + 2900 | 900 | 0900 +(20 rows) + -- Merge Append cases EXPLAIN (VERBOSE, COSTS OFF) SELECT * FROM async_pt WHERE b % 100 = 0 ORDER BY b, a; diff --git a/contrib/postgres_fdw/sql/postgres_fdw.sql b/contrib/postgres_fdw/sql/postgres_fdw.sql index 5d6caf0e41e..2c70dec2213 100644 --- a/contrib/postgres_fdw/sql/postgres_fdw.sql +++ b/contrib/postgres_fdw/sql/postgres_fdw.sql @@ -4291,6 +4291,10 @@ INSERT INTO result_tbl SELECT a, b, 'AAA' || c FROM async_pt WHERE b === 505; SELECT * FROM result_tbl ORDER BY a; DELETE FROM result_tbl; +EXPLAIN (VERBOSE, COSTS OFF) +SELECT * FROM async_pt WHERE b % 100 = 0 ORDER BY a; +SELECT * FROM async_pt WHERE b % 100 = 0 ORDER BY a; + -- Merge Append cases EXPLAIN (VERBOSE, COSTS OFF) SELECT * FROM async_pt WHERE b % 100 = 0 ORDER BY b, a; diff --git a/src/backend/optimizer/plan/createplan.c b/src/backend/optimizer/plan/createplan.c index 73438e76945..2b9d00e1b9c 100644 --- a/src/backend/optimizer/plan/createplan.c +++ b/src/backend/optimizer/plan/createplan.c @@ -1298,7 +1298,7 @@ create_append_plan(PlannerInfo *root, AppendPath *best_path, int flags) } /* If appropriate, consider async append */ - consider_async = (enable_async_append && pathkeys == NIL && + consider_async = (enable_async_append && !best_path->path.parallel_safe && list_length(best_path->subpaths) > 1); @@ -1307,6 +1307,7 @@ create_append_plan(PlannerInfo *root, AppendPath *best_path, int flags) { Path *subpath = (Path *) lfirst(subpaths); Plan *subplan; + bool created_sort_plan = false; /* Must insist that all children return the same tlist */ subplan = create_plan_recurse(root, subpath, CP_EXACT_TLIST); @@ -1390,11 +1391,12 @@ create_append_plan(PlannerInfo *root, AppendPath *best_path, int flags) } subplan = sort_plan; + created_sort_plan = true; } } /* If needed, check to see if subplan can be executed asynchronously */ - if (consider_async && mark_async_capable_plan(subplan, subpath)) + if (consider_async && !created_sort_plan && mark_async_capable_plan(subplan, subpath)) { Assert(subplan->async_capable); ++nasyncplans; -- 2.43.0