Re: strange 'vacuum verbose analyze' behaviour

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: Oleg Bartunov <oleg(at)sai(dot)msu(dot)su>
Cc: Pgsql Hackers <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: strange 'vacuum verbose analyze' behaviour
Date: 2005-01-27 19:06:56
Message-ID: 22985.1106852816@sss.pgh.pa.us
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Oleg Bartunov <oleg(at)sai(dot)msu(dot)su> writes:
> Day ago we run 'vacuum verbose analyze;' and now we're observing
> strange output (see below). We see many repeated passes through the
> table 'usno' and all indices (2).

Nothing strange about it: that's how vacuum deals with large tables.
You can reduce the number of passes over the indexes by increasing
maintenance_work_mem (aka vacuum_mem). It looks like you have that
set to 16MB, which is enough to hold about 2.79M 6-byte CTIDs. When
that fills up, we have to go and clean out the corresponding index
entries before we resume scanning the heap.

It is a bit odd that nothing is getting deleted from "ipix_ind" ...
is that a partial index?

regards, tom lane

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