From 1eeee69099e0402722457534df4744d8679bbe23 Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Thu, 7 Feb 2019 13:10:46 -0500 Subject: Ensure that foreign scans with lateral refs are planned correctly. As reported in bug #15613 from Srinivasan S A, file_fdw and postgres_fdw neglected to mark plain baserel foreign paths as parameterized when the relation has lateral_relids. Other FDWs have surely copied this mistake, so rather than just patching those two modules, install a band-aid fix in create_foreignscan_path to rectify the mistake centrally. Although the band-aid is enough to fix the visible symptom, correct the calls in file_fdw and postgres_fdw anyway, so that they are valid examples for external FDWs. Also, since the band-aid isn't enough to make this work for parameterized foreign joins, throw an elog(ERROR) if such a case is passed to create_foreignscan_path. This shouldn't pose much of a problem for existing external FDWs, since it's likely they aren't trying to make such paths anyway (though some of them may need a defense against joins with lateral_relids, similar to the one this patch installs into postgres_fdw). Add some assertions in relnode.c to catch future occurrences of the same error --- in particular, as backstop against core-code mistakes like the one fixed by commit bdd9a99aa. Discussion: https://postgr.es/m/15613-092be1be9576c728@postgresql.org --- contrib/postgres_fdw/sql/postgres_fdw.sql | 26 ++++++++++++++++++++++++++ 1 file changed, 26 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 698be8e2917..a439239bff6 100644 --- a/contrib/postgres_fdw/sql/postgres_fdw.sql +++ b/contrib/postgres_fdw/sql/postgres_fdw.sql @@ -238,6 +238,32 @@ WHERE a.c2 = 6 AND b.c1 = a.c1 AND a.c8 = 'foo' AND b.c7 = upper(a.c7); SELECT * FROM ft1 WHERE c1 = ANY (ARRAY(SELECT c1 FROM ft2 WHERE c1 < 5)); SELECT * FROM ft2 WHERE c1 = ANY (ARRAY(SELECT c1 FROM ft1 WHERE c1 < 5)); +-- bug #15613: bad plan for foreign table scan with lateral reference +EXPLAIN (VERBOSE, COSTS OFF) +SELECT ref_0.c2, subq_1.* +FROM + "S 1"."T 1" AS ref_0, + LATERAL ( + SELECT ref_0."C 1" c1, subq_0.* + FROM (SELECT ref_0.c2, ref_1.c3 + FROM ft1 AS ref_1) AS subq_0 + RIGHT JOIN ft2 AS ref_3 ON (subq_0.c3 = ref_3.c3) + ) AS subq_1 +WHERE ref_0."C 1" < 10 AND subq_1.c3 = '00001' +ORDER BY ref_0."C 1"; + +SELECT ref_0.c2, subq_1.* +FROM + "S 1"."T 1" AS ref_0, + LATERAL ( + SELECT ref_0."C 1" c1, subq_0.* + FROM (SELECT ref_0.c2, ref_1.c3 + FROM ft1 AS ref_1) AS subq_0 + RIGHT JOIN ft2 AS ref_3 ON (subq_0.c3 = ref_3.c3) + ) AS subq_1 +WHERE ref_0."C 1" < 10 AND subq_1.c3 = '00001' +ORDER BY ref_0."C 1"; + -- =================================================================== -- parameterized queries -- =================================================================== -- cgit v1.2.3