| From: | Peter Geoghegan <pg(at)heroku(dot)com> |
|---|---|
| To: | Simon Riggs <simon(at)2ndquadrant(dot)com> |
| Cc: | Andres Freund <andres(at)2ndquadrant(dot)com>, Josh Berkus <josh(at)agliodbs(dot)com>, Greg Stark <stark(at)mit(dot)edu>, PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: ANALYZE sampling is too good |
| Date: | 2013-12-10 19:49:12 |
| Message-ID: | CAM3SWZQDDA2MrFpfCpxM05Ypr0WueejQbbvVNPcXsMKr9KHWWg@mail.gmail.com |
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| Lists: | pgsql-hackers |
On Tue, Dec 10, 2013 at 11:23 AM, Simon Riggs <simon(at)2ndquadrant(dot)com> wrote:
> However, these things presume that we need to continue scanning most
> of the blocks of the table, which I don't think needs to be the case.
> There is a better way.
Do they? I think it's one opportunistic way of ameliorating the cost.
> Back in 2005/6, I advocated a block sampling method, as described by
> Chaudri et al (ref?)
I don't think that anyone believes that not doing block sampling is
tenable, fwiw. Clearly some type of block sampling would be preferable
for most or all purposes.
--
Peter Geoghegan
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