Re: Better default_statistics_target
От | Greg Sabino Mullane |
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Тема | Re: Better default_statistics_target |
Дата | |
Msg-id | 8230f4174652fe68d79902f17a271afb@biglumber.com обсуждение исходный текст |
Ответ на | Re: Overhauling GUCS (Tom Lane <tgl@sss.pgh.pa.us>) |
Ответы |
Re: Better default_statistics_target
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Список | pgsql-hackers |
-----BEGIN PGP SIGNED MESSAGE----- Hash: RIPEMD160 > That was a pretty special case (LIKE/regex estimation), and we've since > eliminated the threshold change in the LIKE/regex estimates anyway, so > there's no longer any reason to pick 100 as opposed to any other number. > So we're still back at "what's a good value and why?". Glad to hear that, although I think this is only in HEAD, not backpatched, right? Well at any rate, I withdraw my strong support for 100 and join in the quest for a good number. The "anything but 10" campaign. > I'm still concerned about the fact that eqjoinsel() is O(N^2). Show me > some measurements demonstrating that a deep nest of equijoins doesn't > get noticeably more expensive to plan --- preferably on a datatype with > an expensive equality operator, eg numeric --- and I'm on board. I hope someone else on the list can do this, because I can't. :) - -- Greg Sabino Mullane greg@turnstep.com PGP Key: 0x14964AC8 200806122054 http://biglumber.com/x/web?pk=2529DF6AB8F79407E94445B4BC9B906714964AC8 -----BEGIN PGP SIGNATURE----- iEYEAREDAAYFAkhRxToACgkQvJuQZxSWSsj0OwCfel+zN/jQth79RvIHtxpUefQD APMAmQEKIDS6BzqUjn4eTMzP9NDlxTbE =JZTe -----END PGP SIGNATURE-----
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