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Repair bogus EPQ plans generated for postgres_fdw foreign joins.

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postgres_fdw's postgresGetForeignPlan() assumes without checking that the
outer_plan it's given for a join relation must have a NestLoop, MergeJoin,
or HashJoin node at the top.  That's been wrong at least since commit
4bbf6edfb (which could cause insertion of a Sort node on top) and it seems
like a pretty unsafe thing to Just Assume even without that.

Through blind good fortune, this doesn't seem to have any worse
consequences today than strange EXPLAIN output, but it's clearly trouble
waiting to happen.

To fix, test the node type explicitly before touching Join-specific
fields, and avoid jamming the new tlist into a node type that can't
do projection.  Export a new support function from createplan.c
to avoid building low-level knowledge about the latter into FDWs.

Back-patch to 9.6 where the faulty coding was added.  Note that the
associated regression test cases don't show any changes before v11,
apparently because the tests back-patched with 4bbf6edfb don't actually
exercise the problem case before then (there's no top-level Sort
in those plans).

Discussion: https://postgr.es/m/8946.1544644803@sss.pgh.pa.us
This commit is contained in:
Tom Lane
2018-12-12 16:08:30 -05:00
parent 0f7ec8d9c3
commit 77d4d88afb
4 changed files with 140 additions and 89 deletions
Download Patch File Download Diff File Expand all files Collapse all files

136
contrib/postgres_fdw/expected/postgres_fdw.out
View File

@ -1701,25 +1701,27 @@ SELECT t1.c1, t2.c1 FROM ft1 t1 JOIN ft2 t2 ON (t1.c1 = t2.c1) ORDER BY t1.c3, t
Output: t1.c1, t2.c1, t1.c3, t1.*, t2.*
Relations: (public.ft1 t1) INNER JOIN (public.ft2 t2)
Remote SQL: SELECT r1."C 1", r2."C 1", r1.c3, CASE WHEN (r1.*)::text IS NOT NULL THEN ROW(r1."C 1", r1.c2, r1.c3, r1.c4, r1.c5, r1.c6, r1.c7, r1.c8) END, CASE WHEN (r2.*)::text IS NOT NULL THEN ROW(r2."C 1", r2.c2, r2.c3, r2.c4, r2.c5, r2.c6, r2.c7, r2.c8) END FROM ("S 1"."T 1" r1 INNER JOIN "S 1"."T 1" r2 ON (((r1."C 1" = r2."C 1")))) ORDER BY r1.c3 ASC NULLS LAST, r1."C 1" ASC NULLS LAST FOR UPDATE OF r1
-> Sort
Output: t1.c1, t1.c3, t1.*, t2.c1, t2.*
Sort Key: t1.c3 USING <, t1.c1
-> Merge Join
-> Result
Output: t1.c1, t2.c1, t1.c3, t1.*, t2.*
-> Sort
Output: t1.c1, t1.c3, t1.*, t2.c1, t2.*
Merge Cond: (t1.c1 = t2.c1)
-> Sort
Output: t1.c1, t1.c3, t1.*
Sort Key: t1.c1
-> Foreign Scan on public.ft1 t1
Sort Key: t1.c3, t1.c1
-> Merge Join
Output: t1.c1, t1.c3, t1.*, t2.c1, t2.*
Merge Cond: (t1.c1 = t2.c1)
-> Sort
Output: t1.c1, t1.c3, t1.*
Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" FOR UPDATE
-> Sort
Output: t2.c1, t2.*
Sort Key: t2.c1
-> Foreign Scan on public.ft2 t2
Sort Key: t1.c1
-> Foreign Scan on public.ft1 t1
Output: t1.c1, t1.c3, t1.*
Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" FOR UPDATE
-> Sort
Output: t2.c1, t2.*
Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1"
(26 rows)
Sort Key: t2.c1
-> Foreign Scan on public.ft2 t2
Output: t2.c1, t2.*
Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1"
(28 rows)
SELECT t1.c1, t2.c1 FROM ft1 t1 JOIN ft2 t2 ON (t1.c1 = t2.c1) ORDER BY t1.c3, t1.c1 OFFSET 100 LIMIT 10 FOR UPDATE OF t1;
c1 | c1
@ -1748,25 +1750,27 @@ SELECT t1.c1, t2.c1 FROM ft1 t1 JOIN ft2 t2 ON (t1.c1 = t2.c1) ORDER BY t1.c3, t
Output: t1.c1, t2.c1, t1.c3, t1.*, t2.*
Relations: (public.ft1 t1) INNER JOIN (public.ft2 t2)
Remote SQL: SELECT r1."C 1", r2."C 1", r1.c3, CASE WHEN (r1.*)::text IS NOT NULL THEN ROW(r1."C 1", r1.c2, r1.c3, r1.c4, r1.c5, r1.c6, r1.c7, r1.c8) END, CASE WHEN (r2.*)::text IS NOT NULL THEN ROW(r2."C 1", r2.c2, r2.c3, r2.c4, r2.c5, r2.c6, r2.c7, r2.c8) END FROM ("S 1"."T 1" r1 INNER JOIN "S 1"."T 1" r2 ON (((r1."C 1" = r2."C 1")))) ORDER BY r1.c3 ASC NULLS LAST, r1."C 1" ASC NULLS LAST FOR UPDATE OF r1 FOR UPDATE OF r2
-> Sort
Output: t1.c1, t1.c3, t1.*, t2.c1, t2.*
Sort Key: t1.c3 USING <, t1.c1
-> Merge Join
-> Result
Output: t1.c1, t2.c1, t1.c3, t1.*, t2.*
-> Sort
Output: t1.c1, t1.c3, t1.*, t2.c1, t2.*
Merge Cond: (t1.c1 = t2.c1)
-> Sort
Output: t1.c1, t1.c3, t1.*
Sort Key: t1.c1
-> Foreign Scan on public.ft1 t1
Sort Key: t1.c3, t1.c1
-> Merge Join
Output: t1.c1, t1.c3, t1.*, t2.c1, t2.*
Merge Cond: (t1.c1 = t2.c1)
-> Sort
Output: t1.c1, t1.c3, t1.*
Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" FOR UPDATE
-> Sort
Output: t2.c1, t2.*
Sort Key: t2.c1
-> Foreign Scan on public.ft2 t2
Sort Key: t1.c1
-> Foreign Scan on public.ft1 t1
Output: t1.c1, t1.c3, t1.*
Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" FOR UPDATE
-> Sort
Output: t2.c1, t2.*
Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" FOR UPDATE
(26 rows)
Sort Key: t2.c1
-> Foreign Scan on public.ft2 t2
Output: t2.c1, t2.*
Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" FOR UPDATE
(28 rows)
SELECT t1.c1, t2.c1 FROM ft1 t1 JOIN ft2 t2 ON (t1.c1 = t2.c1) ORDER BY t1.c3, t1.c1 OFFSET 100 LIMIT 10 FOR UPDATE;
c1 | c1
@ -1796,25 +1800,27 @@ SELECT t1.c1, t2.c1 FROM ft1 t1 JOIN ft2 t2 ON (t1.c1 = t2.c1) ORDER BY t1.c3, t
Output: t1.c1, t2.c1, t1.c3, t1.*, t2.*
Relations: (public.ft1 t1) INNER JOIN (public.ft2 t2)
Remote SQL: SELECT r1."C 1", r2."C 1", r1.c3, CASE WHEN (r1.*)::text IS NOT NULL THEN ROW(r1."C 1", r1.c2, r1.c3, r1.c4, r1.c5, r1.c6, r1.c7, r1.c8) END, CASE WHEN (r2.*)::text IS NOT NULL THEN ROW(r2."C 1", r2.c2, r2.c3, r2.c4, r2.c5, r2.c6, r2.c7, r2.c8) END FROM ("S 1"."T 1" r1 INNER JOIN "S 1"."T 1" r2 ON (((r1."C 1" = r2."C 1")))) ORDER BY r1.c3 ASC NULLS LAST, r1."C 1" ASC NULLS LAST FOR SHARE OF r1
-> Sort
Output: t1.c1, t1.c3, t1.*, t2.c1, t2.*
Sort Key: t1.c3 USING <, t1.c1
-> Merge Join
-> Result
Output: t1.c1, t2.c1, t1.c3, t1.*, t2.*
-> Sort
Output: t1.c1, t1.c3, t1.*, t2.c1, t2.*
Merge Cond: (t1.c1 = t2.c1)
-> Sort
Output: t1.c1, t1.c3, t1.*
Sort Key: t1.c1
-> Foreign Scan on public.ft1 t1
Sort Key: t1.c3, t1.c1
-> Merge Join
Output: t1.c1, t1.c3, t1.*, t2.c1, t2.*
Merge Cond: (t1.c1 = t2.c1)
-> Sort
Output: t1.c1, t1.c3, t1.*
Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" FOR SHARE
-> Sort
Output: t2.c1, t2.*
Sort Key: t2.c1
-> Foreign Scan on public.ft2 t2
Sort Key: t1.c1
-> Foreign Scan on public.ft1 t1
Output: t1.c1, t1.c3, t1.*
Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" FOR SHARE
-> Sort
Output: t2.c1, t2.*
Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1"
(26 rows)
Sort Key: t2.c1
-> Foreign Scan on public.ft2 t2
Output: t2.c1, t2.*
Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1"
(28 rows)
SELECT t1.c1, t2.c1 FROM ft1 t1 JOIN ft2 t2 ON (t1.c1 = t2.c1) ORDER BY t1.c3, t1.c1 OFFSET 100 LIMIT 10 FOR SHARE OF t1;
c1 | c1
@ -1843,25 +1849,27 @@ SELECT t1.c1, t2.c1 FROM ft1 t1 JOIN ft2 t2 ON (t1.c1 = t2.c1) ORDER BY t1.c3, t
Output: t1.c1, t2.c1, t1.c3, t1.*, t2.*
Relations: (public.ft1 t1) INNER JOIN (public.ft2 t2)
Remote SQL: SELECT r1."C 1", r2."C 1", r1.c3, CASE WHEN (r1.*)::text IS NOT NULL THEN ROW(r1."C 1", r1.c2, r1.c3, r1.c4, r1.c5, r1.c6, r1.c7, r1.c8) END, CASE WHEN (r2.*)::text IS NOT NULL THEN ROW(r2."C 1", r2.c2, r2.c3, r2.c4, r2.c5, r2.c6, r2.c7, r2.c8) END FROM ("S 1"."T 1" r1 INNER JOIN "S 1"."T 1" r2 ON (((r1."C 1" = r2."C 1")))) ORDER BY r1.c3 ASC NULLS LAST, r1."C 1" ASC NULLS LAST FOR SHARE OF r1 FOR SHARE OF r2
-> Sort
Output: t1.c1, t1.c3, t1.*, t2.c1, t2.*
Sort Key: t1.c3 USING <, t1.c1
-> Merge Join
-> Result
Output: t1.c1, t2.c1, t1.c3, t1.*, t2.*
-> Sort
Output: t1.c1, t1.c3, t1.*, t2.c1, t2.*
Merge Cond: (t1.c1 = t2.c1)
-> Sort
Output: t1.c1, t1.c3, t1.*
Sort Key: t1.c1
-> Foreign Scan on public.ft1 t1
Sort Key: t1.c3, t1.c1
-> Merge Join
Output: t1.c1, t1.c3, t1.*, t2.c1, t2.*
Merge Cond: (t1.c1 = t2.c1)
-> Sort
Output: t1.c1, t1.c3, t1.*
Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" FOR SHARE
-> Sort
Output: t2.c1, t2.*
Sort Key: t2.c1
-> Foreign Scan on public.ft2 t2
Sort Key: t1.c1
-> Foreign Scan on public.ft1 t1
Output: t1.c1, t1.c3, t1.*
Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" FOR SHARE
-> Sort
Output: t2.c1, t2.*
Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" FOR SHARE
(26 rows)
Sort Key: t2.c1
-> Foreign Scan on public.ft2 t2
Output: t2.c1, t2.*
Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" FOR SHARE
(28 rows)
SELECT t1.c1, t2.c1 FROM ft1 t1 JOIN ft2 t2 ON (t1.c1 = t2.c1) ORDER BY t1.c3, t1.c1 OFFSET 100 LIMIT 10 FOR SHARE;
c1 | c1