Re: AW: question about index cost estimates - Mailing list pgsql-hackers

From Tom Lane
Subject Re: AW: question about index cost estimates
Date
Msg-id 24065.958667343@sss.pgh.pa.us
Whole thread Raw
In response to RE: AW: question about index cost estimates  (Hiroshi Inoue <Inoue@tpf.co.jp>)
List pgsql-hackers
Hiroshi Inoue <Inoue@tpf.co.jp> writes:
> So how about a kind of sample scanning in a separate ANALYZE
> command ?

I do think it'd be a good idea to separate out the stats-gathering
into an ANALYZE command that can be invoked separately from VACUUM.
For one thing, there's no good reason to hold down an exclusive
lock on the target table while we are gathering stats.

But that doesn't answer the question: how can we measure the extent
to which a table is in the same order as an index?  And even that
is too one-dimensional a concept to apply to r-tree indexes, for
example.  What do we do for r-trees?
        regards, tom lane


pgsql-hackers by date:

Previous
From: Hiroshi Inoue
Date:
Subject: RE: AW: question about index cost estimates
Next
From: Alessio Bragadini
Date:
Subject: The New Slashdot Setup (includes MySql server)