diff options
| author | Tom Lane | 2021-07-07 19:21:25 +0000 |
|---|---|---|
| committer | Tom Lane | 2021-07-07 19:21:25 +0000 |
| commit | b9734c13f168ef0d487aa122e486ca9b6dd6aa59 (patch) | |
| tree | 0076995b29ba2dd520431156e29b276d7c56d8fb | |
| parent | 9d2a7757347cb1adb48599fce4dcde0f1fc9e9ae (diff) | |
Fix crash in postgres_fdw for provably-empty remote UPDATE/DELETE.
In 86dc90056, I'd written find_modifytable_subplan with the assumption
that if the immediate child of a ModifyTable is a Result, it must be
a projecting Result with a subplan. However, if the UPDATE or DELETE
has a provably-constant-false WHERE clause, that's not so: we'll
generate a dummy subplan with a childless Result. Add the missing
null-check so we don't crash on such cases.
Per report from Alexander Pyhalov.
Discussion: https://postgr.es/m/b9a6f53549456b2f3e2fd150dcd79d72@postgrespro.ru
| -rw-r--r-- | contrib/postgres_fdw/expected/postgres_fdw.out | 20 | ||||
| -rw-r--r-- | contrib/postgres_fdw/postgres_fdw.c | 4 | ||||
| -rw-r--r-- | contrib/postgres_fdw/sql/postgres_fdw.sql | 4 |
3 files changed, 27 insertions, 1 deletions
diff --git a/contrib/postgres_fdw/expected/postgres_fdw.out b/contrib/postgres_fdw/expected/postgres_fdw.out index b510322c4ea..b8561d6a3c4 100644 --- a/contrib/postgres_fdw/expected/postgres_fdw.out +++ b/contrib/postgres_fdw/expected/postgres_fdw.out @@ -6853,6 +6853,26 @@ DROP TRIGGER trig_row_before ON rem1; DROP TRIGGER trig_row_after ON rem1; DROP TRIGGER trig_local_before ON loc1; -- Test direct foreign table modification functionality +EXPLAIN (verbose, costs off) +DELETE FROM rem1; -- can be pushed down + QUERY PLAN +--------------------------------------------- + Delete on public.rem1 + -> Foreign Delete on public.rem1 + Remote SQL: DELETE FROM public.loc1 +(3 rows) + +EXPLAIN (verbose, costs off) +DELETE FROM rem1 WHERE false; -- currently can't be pushed down + QUERY PLAN +------------------------------------------------------- + Delete on public.rem1 + Remote SQL: DELETE FROM public.loc1 WHERE ctid = $1 + -> Result + Output: ctid + One-Time Filter: false +(5 rows) + -- Test with statement-level triggers CREATE TRIGGER trig_stmt_before BEFORE DELETE OR INSERT OR UPDATE ON rem1 diff --git a/contrib/postgres_fdw/postgres_fdw.c b/contrib/postgres_fdw/postgres_fdw.c index 5cf10402a20..f15c97ad7a4 100644 --- a/contrib/postgres_fdw/postgres_fdw.c +++ b/contrib/postgres_fdw/postgres_fdw.c @@ -2370,7 +2370,9 @@ find_modifytable_subplan(PlannerInfo *root, if (subplan_index < list_length(appendplan->appendplans)) subplan = (Plan *) list_nth(appendplan->appendplans, subplan_index); } - else if (IsA(subplan, Result) && IsA(outerPlan(subplan), Append)) + else if (IsA(subplan, Result) && + outerPlan(subplan) != NULL && + IsA(outerPlan(subplan), Append)) { Append *appendplan = (Append *) outerPlan(subplan); diff --git a/contrib/postgres_fdw/sql/postgres_fdw.sql b/contrib/postgres_fdw/sql/postgres_fdw.sql index 911f171d812..c283e747154 100644 --- a/contrib/postgres_fdw/sql/postgres_fdw.sql +++ b/contrib/postgres_fdw/sql/postgres_fdw.sql @@ -1738,6 +1738,10 @@ DROP TRIGGER trig_local_before ON loc1; -- Test direct foreign table modification functionality +EXPLAIN (verbose, costs off) +DELETE FROM rem1; -- can be pushed down +EXPLAIN (verbose, costs off) +DELETE FROM rem1 WHERE false; -- currently can't be pushed down -- Test with statement-level triggers CREATE TRIGGER trig_stmt_before |