From: | Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us> |
---|---|
To: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
Cc: | "Mikheev, Vadim" <vmikheev(at)SECTORBASE(dot)COM>, "'Hiroshi Inoue'" <Inoue(at)tpf(dot)co(dot)jp>, Ryan Bradetich <ryan_bradetich(at)hp(dot)com>, pgsql-sql(at)postgresql(dot)org |
Subject: | Re: Use of index in 7.0 vs 6.5 |
Date: | 2000-05-25 16:08:45 |
Message-ID: | 200005251608.MAA25042@candle.pha.pa.us |
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Lists: | pgsql-sql |
> Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us> writes:
> > That certainly would make sense. We have hesitated to gather more
> > statistics because of the time involved. Fuller statistics on just the
> > indexed columns could be a big win and be done fairly quickly because
> > the rows are already sorted in the index.
>
> Yeah, a scan over just the index itself would be a perfect way to
> gather stats. The normal objection to it (can't tell whether entries
> correspond to currently-valid tuples) doesn't apply, because we don't
> really care whether the stats are perfectly accurate.
>
> Should put this in TODO, along with something about splitting the
> ANALYZE function out of VACUUM and making it invokable as a separate
> statement.
Added:
* Remove ANALYZE from VACUUM so it can be run separately without locks
* Gather more accurate statistics using indexes
--
Bruce Momjian | http://www.op.net/~candle
pgman(at)candle(dot)pha(dot)pa(dot)us | (610) 853-3000
+ If your life is a hard drive, | 830 Blythe Avenue
+ Christ can be your backup. | Drexel Hill, Pennsylvania 19026
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