| From: | bricklen <bricklen(at)gmail(dot)com> |
|---|---|
| To: | Neil Whelchel <neil(dot)whelchel(at)gmail(dot)com> |
| Cc: | pgsql-performance(at)postgresql(dot)org |
| Subject: | Re: Slow count(*) again... |
| Date: | 2010-10-12 15:12:53 |
| Message-ID: | AANLkTimXSWapozrZNdiRXDSm2hdsha1As94NwuS967As@mail.gmail.com |
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| Lists: | pgsql-hackers pgsql-performance |
On Sat, Oct 9, 2010 at 4:26 PM, Neil Whelchel <neil(dot)whelchel(at)gmail(dot)com> wrote:
> Maybe an
> estimate(*) that works like count but gives an answer from the index without
> checking visibility? I am sure that this would be good enough to make a page
> list, it is really no big deal if it errors on the positive side, maybe the
> list of pages has an extra page off the end. I can live with that. What I
> can't live with is taking 13 seconds to get a page of results from 850,000
> rows in a table.
> -Neil-
>
FWIW, Michael Fuhr wrote a small function to parse the EXPLAIN plan a
few years ago and it works pretty well assuming your stats are up to
date.
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