Re: No hash join across partitioned tables?
От | Bruce Momjian |
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Тема | Re: No hash join across partitioned tables? |
Дата | |
Msg-id | 201007020300.o62300V21807@momjian.us обсуждение исходный текст |
Ответ на | Re: No hash join across partitioned tables? (Tom Lane <tgl@sss.pgh.pa.us>) |
Ответы |
Re: No hash join across partitioned tables?
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Список | pgsql-performance |
Tom Lane wrote: > Robert Haas <robertmhaas@gmail.com> writes: > > In going back through emails I had marked as possibly needing another > > look before 9.0 is released, I came across this issue again. As I > > understand it, analyze (or analyse) now collects statistics for both > > the parent individually, and for the parent and its children together. > > However, as I further understand it, autovacuum won't actually fire > > off an analyze unless there's enough activity on the parent table > > considered individually to warrant it. So if you have an empty parent > > and a bunch of children with data in it, your stats will still stink, > > unless you analyze by hand. > > Check. > > > Assuming my understanding of the problem is correct, we could: > > > (a) fix it, > > (b) document that you should consider periodic manual analyze commands > > in this situation, or > > (c) do nothing. > > > Thoughts? > > The objections to (a) are that it might result in excessive ANALYZE work > if not done intelligently, and that we haven't got a patch ready anyway. > I would have liked to get to this for 9.0 but I feel it's a bit late > now. What do we want to do about the above issue? -- Bruce Momjian <bruce@momjian.us> http://momjian.us EnterpriseDB http://enterprisedb.com + None of us is going to be here forever. +
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