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Stabilize postgres_fdw tests on 32-bit machines

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cac169d68 adjusted DEFAULT_FDW_TUPLE_COST and that seems to have caused
a test to become unstable on 32-bit machines.

4b14e1871 tried to fix this as originally the plan was flipping between
a Nested Loop and Hash Join.  That commit forced the Nested Loop, but
there's still flexibility to push or not push the sort to the remote
server and 32-bit seems to prefer to push and on 64-bit, the costs
prefer not to.

Here let's just turn off enable_sort to significantly encourage the sort
to take place on the remote server.

Reported-by: Michael Paquier, Richard Guo
Discussion: https://postgr.es/m/ZUM2IhA8X2lrG50K@paquier.xyz
This commit is contained in:
David Rowley 2023-11-03 12:35:37 +13:00
parent 0bc726d95a
commit b690e5facb
2 changed files with 16 additions and 15 deletions
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29
contrib/postgres_fdw/expected/postgres_fdw.out
View File

@ -4019,27 +4019,25 @@ EXECUTE st1(101, 101);
(1 row)
SET enable_hashjoin TO off;
SET enable_sort TO off;
-- subquery using stable function (can't be sent to remote)
PREPARE st2(int) AS SELECT * FROM ft1 t1 WHERE t1.c1 < $2 AND t1.c3 IN (SELECT c3 FROM ft2 t2 WHERE c1 > $1 AND date(c4) = '1970-01-17'::date) ORDER BY c1;
EXPLAIN (VERBOSE, COSTS OFF) EXECUTE st2(10, 20);
QUERY PLAN
----------------------------------------------------------------------------------------------------------
Sort
QUERY PLAN
----------------------------------------------------------------------------------------------------------------------------------
Nested Loop Semi Join
Output: t1.c1, t1.c2, t1.c3, t1.c4, t1.c5, t1.c6, t1.c7, t1.c8
Sort Key: t1.c1
-> Nested Loop Semi Join
Join Filter: (t2.c3 = t1.c3)
-> Foreign Scan on public.ft1 t1
Output: t1.c1, t1.c2, t1.c3, t1.c4, t1.c5, t1.c6, t1.c7, t1.c8
Join Filter: (t2.c3 = t1.c3)
-> Foreign Scan on public.ft1 t1
Output: t1.c1, t1.c2, t1.c3, t1.c4, t1.c5, t1.c6, t1.c7, t1.c8
Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" WHERE (("C 1" < 20))
-> Materialize
Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" WHERE (("C 1" < 20)) ORDER BY "C 1" ASC NULLS LAST
-> Materialize
Output: t2.c3
-> Foreign Scan on public.ft2 t2
Output: t2.c3
-> Foreign Scan on public.ft2 t2
Output: t2.c3
Filter: (date(t2.c4) = '01-17-1970'::date)
Remote SQL: SELECT c3, c4 FROM "S 1"."T 1" WHERE (("C 1" > 10))
(15 rows)
Filter: (date(t2.c4) = '01-17-1970'::date)
Remote SQL: SELECT c3, c4 FROM "S 1"."T 1" WHERE (("C 1" > 10))
(12 rows)
EXECUTE st2(10, 20);
c1 | c2 | c3 | c4 | c5 | c6 | c7 | c8
@ -4054,6 +4052,7 @@ EXECUTE st2(101, 121);
(1 row)
RESET enable_hashjoin;
RESET enable_sort;
-- subquery using immutable function (can be sent to remote)
PREPARE st3(int) AS SELECT * FROM ft1 t1 WHERE t1.c1 < $2 AND t1.c3 IN (SELECT c3 FROM ft2 t2 WHERE c1 > $1 AND date(c5) = '1970-01-17'::date) ORDER BY c1;
EXPLAIN (VERBOSE, COSTS OFF) EXECUTE st3(10, 20);

2
contrib/postgres_fdw/sql/postgres_fdw.sql
View File

@ -1123,12 +1123,14 @@ EXPLAIN (VERBOSE, COSTS OFF) EXECUTE st1(1, 2);
EXECUTE st1(1, 1);
EXECUTE st1(101, 101);
SET enable_hashjoin TO off;
SET enable_sort TO off;
-- subquery using stable function (can't be sent to remote)
PREPARE st2(int) AS SELECT * FROM ft1 t1 WHERE t1.c1 < $2 AND t1.c3 IN (SELECT c3 FROM ft2 t2 WHERE c1 > $1 AND date(c4) = '1970-01-17'::date) ORDER BY c1;
EXPLAIN (VERBOSE, COSTS OFF) EXECUTE st2(10, 20);
EXECUTE st2(10, 20);
EXECUTE st2(101, 121);
RESET enable_hashjoin;
RESET enable_sort;
-- subquery using immutable function (can be sent to remote)
PREPARE st3(int) AS SELECT * FROM ft1 t1 WHERE t1.c1 < $2 AND t1.c3 IN (SELECT c3 FROM ft2 t2 WHERE c1 > $1 AND date(c5) = '1970-01-17'::date) ORDER BY c1;
EXPLAIN (VERBOSE, COSTS OFF) EXECUTE st3(10, 20);