coredump of 9.3.2
Hi!
Rather simple script (original query was a 500 lines of SQL with >100 Mb of
gzipped dump. Query is looked strange, but actually it was auto-generated):
CREATE TABLE t (a int, b int);
CREATE TABLE tt (c int);
INSERT INTO t VALUES (1,1), (2,2);
INSERT INTO tt VALUES (2);
SELECT
*
FROM
t
WHERE (
CASE
WHEN a%2 IN (SELECT c FROM tt) THEN a
END IN (SELECT c FROM tt)
);
I suppose, the problem is connected to hashed subplan, but I'm not very familiar
with executor. And this affects all supported versions of pgsql.
--
Teodor Sigaev E-mail: teodor@sigaev.ru
WWW: http://www.sigaev.ru/
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On 12/10/2013 09:39 AM, Teodor Sigaev wrote:
SELECT
*
FROM
t
WHERE (
CASE
WHEN a%2 IN (SELECT c FROM tt) THEN a
END IN (SELECT c FROM tt)
);
Wow, it wouldn't have occured to me that that was even supported syntax.
I'm not suprised that it doesn't work ...
--
Josh Berkus
PostgreSQL Experts Inc.
http://pgexperts.com
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Import Notes
Reply to msg id not found: WM18351d80385ff3efc6f804b7eac03dc78fa5b0173af56b81a4ccda72669a82fbbd4494c2e223eab25ecb6733780fcdf8@asav-3.01.com
Teodor Sigaev <teodor@sigaev.ru> writes:
SELECT
*
FROM
t
WHERE (
CASE
WHEN a%2 IN (SELECT c FROM tt) THEN a
END IN (SELECT c FROM tt)
);
I suppose, the problem is connected to hashed subplan, but I'm not very familiar
with executor. And this affects all supported versions of pgsql.
It seems to be a planner bug: it's doing the wrong thing with the
PARAM_SUBLINK Params for the nested IN SubLinks. (They don't look
to be nested textually, but they are, and convert_testexpr is
mistakenly replacing the inner one's Params when it should only
be replacing the outer one's Params.)
I think this has probably been broken since about 2005 :-(.
The comment on convert_testexpr claims it doesn't need to worry
about nested cases; which is true when it's called during
SS_process_sublinks, but not so much when it's called from
convert_ANY_sublink_to_join. Some digging in the git history
suggests that the latter call existed at the time, meaning the
comment was wrong even when written.
regards, tom lane
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