Re: installcheck failing on psql_crosstab
От | Alvaro Herrera |
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Тема | Re: installcheck failing on psql_crosstab |
Дата | |
Msg-id | 20160606152837.GA391408@alvherre.pgsql обсуждение исходный текст |
Ответ на | Re: installcheck failing on psql_crosstab (Tom Lane <tgl@sss.pgh.pa.us>) |
Ответы |
Re: installcheck failing on psql_crosstab
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Список | pgsql-hackers |
Tom Lane wrote: > Alvaro Herrera <alvherre@2ndquadrant.com> writes: > > I can't imagine that the server is avoiding hash aggregation on a 1MB > > work_mem limit for data that's a few dozen of bytes. Is it really doing > > that? > > Yup: Aha. Thanks for testing. > Now that you mention it, this does seem a bit odd, although I remember > that there's a pretty substantial fudge factor in there when we have > no statistics (which we don't in this example). If I ANALYZE ctv_data > then it sticks to the hashagg plan all the way down to 64kB work_mem. Hmm, so we could solve the complaint by adding an ANALYZE. I'm open to that; other opinions? -- Álvaro Herrera http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
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