From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
---|---|
To: | "Kevin Grittner" <Kevin(dot)Grittner(at)wicourts(dot)gov> |
Cc: | "Josh Berkus" <josh(at)agliodbs(dot)com>, "Nathan Boley" <npboley(at)gmail(dot)com>, pgsql-hackers(at)postgresql(dot)org |
Subject: | Re: Thoughts on statistics for continuously advancing columns |
Date: | 2009-12-30 16:16:45 |
Message-ID: | 18031.1262189805@sss.pgh.pa.us |
Views: | Raw Message | Whole Thread | Download mbox | Resend email |
Thread: | |
Lists: | pgsql-hackers |
"Kevin Grittner" <Kevin(dot)Grittner(at)wicourts(dot)gov> writes:
> Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>> I don't have a better idea at the moment :-(
> It's been a while since I've been bitten by this issue -- the last
> time was under Sybase. The Sybase suggestion was to either add
> "dummy rows" [YUCK!] to set the extreme bounds or to "lie to the
> optimizer" by fudging the statistics after each generation. Perhaps
> we could do better by adding columns for high and low bounds to
> pg_statistic. These would not be set by ANALYZE, but
> user-modifiable to cover exactly this problem? NULL would mean
> current behavior?
Well, the problem Josh has got is exactly that a constant high bound
doesn't work.
What I'm wondering about is why he finds that re-running ANALYZE
isn't an acceptable solution. It's supposed to be a reasonably
cheap thing to do.
I think the cleanest solution to this would be to make ANALYZE
cheaper, perhaps by finding some way for it to work incrementally.
regards, tom lane
From | Date | Subject | |
---|---|---|---|
Next Message | Magnus Hagander | 2009-12-30 16:20:08 | Re: krb_server_keyfile setting doesn't work on Windows |
Previous Message | Tom Lane | 2009-12-30 16:10:56 | Re: krb_server_keyfile setting doesn't work on Windows |