From 5c854e7a2c8a6cd26040e0f9949e7a4a007f6366 Mon Sep 17 00:00:00 2001 From: Etsuro Fujita Date: Thu, 28 Apr 2022 15:15:00 +0900 Subject: Disable asynchronous execution if using gating Result nodes. mark_async_capable_plan(), which is called from create_append_plan() to determine whether subplans are async-capable, failed to take into account that the given subplan created from a given subpath might include a gating Result node if the subpath is a SubqueryScanPath or ForeignPath, causing a segmentation fault there when the subplan created from a SubqueryScanPath includes the Result node, or causing ExecAsyncRequest() to throw an error about an unrecognized node type when the subplan created from a ForeignPath includes the Result node, because in the latter case the Result node was unintentionally considered as async-capable, but we don't currently support executing Result nodes asynchronously. Fix by modifying mark_async_capable_plan() to disable asynchronous execution in such cases. Also, adjust code in the ProjectionPath case in mark_async_capable_plan(), for consistency with other cases, and adjust/improve comments there. is_async_capable_path() added in commit 27e1f1456, which was rewritten to mark_async_capable_plan() in a later commit, has the same issue, causing the error at execution mentioned above, so back-patch to v14 where the aforesaid commit went in. Per report from Justin Pryzby. Etsuro Fujita, reviewed by Zhihong Yu and Justin Pryzby. Discussion: https://postgr.es/m/20220408124338.GK24419%40telsasoft.com --- contrib/postgres_fdw/sql/postgres_fdw.sql | 13 +++++++++++++ 1 file changed, 13 insertions(+) (limited to 'contrib/postgres_fdw/sql/postgres_fdw.sql') diff --git a/contrib/postgres_fdw/sql/postgres_fdw.sql b/contrib/postgres_fdw/sql/postgres_fdw.sql index ed181dedff5..92d12120272 100644 --- a/contrib/postgres_fdw/sql/postgres_fdw.sql +++ b/contrib/postgres_fdw/sql/postgres_fdw.sql @@ -3410,6 +3410,19 @@ UNION ALL SELECT * FROM result_tbl ORDER BY a; DELETE FROM result_tbl; +-- Disable 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; -- cgit v1.2.3