Re: UNION ALL on partitioned tables won't use indices.
От | Kyotaro HORIGUCHI |
---|---|
Тема | Re: UNION ALL on partitioned tables won't use indices. |
Дата | |
Msg-id | 20140228.144551.215885523.horiguchi.kyotaro@lab.ntt.co.jp обсуждение исходный текст |
Ответ на | Re: UNION ALL on partitioned tables won't use indices. (Kyotaro HORIGUCHI <horiguchi.kyotaro@lab.ntt.co.jp>) |
Список | pgsql-hackers |
Sorry, I did wrong test. > > > Noah Misch <noah@leadboat.com> writes: > > > > If the attached patch version looks reasonable, I will commit it. > > > > > > The test case is completely bogus, as the query explained is significantly > > > different from the query executed. I'm not sure whether you can just > > > remove the extra ORDER BY column without getting machine-dependent > > > results, though. > > > > Each query tests something slightly different. The EXPLAIN verifies that we > > can MergeAppend given this query structure, and the plain SELECT verifies that > > any join tree contortions we made to achieve that do not change the answer. > > I think Tom said that the second query can yield the same result > even if the 2nd column in orderby is removed so the pertinence of > it seems doubtful. Actually the altered query gave me the same > result on my workset (CentOS6.5/x86-64). No, no! It was actually returned a *different* result. I accidentially(?) added 'desc' to the '2'. Please forget it. regards, -- Kyotaro Horiguchi NTT Open Source Software Center
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