From: Tom Lane <tgl@sss.pgh.pa.us>
To: Steven M. Wheeler <swheeler@sabre.com>
Cc: pgsql-sql@hub.org
Subject: Re: [SQL] Questions about vacuum analyze
Date: Thu, 07 Oct 1999 10:08:30 -0400
Message-ID: <28912.939305310@sss.pgh.pa.us> (raw)
In-Reply-To: <37FC8422.82295F9A@sabre.com>
"Steven M. Wheeler" <swheeler@sabre.com> writes:
> I am now running into another problem. I need to do select distinct from the
> currnt to get dates for maintenance activity (rows to summarize and move to
> history). When ever I do I get this message in my server.log file:
> NOTICE: BufFileRead: should have flushed after writing
Hmph --- just looking at the code that issues that message, it looks
like it is a harmless gripe (it complains, but then goes and does the
missing step). However, it's suggestive that there may be a logic error
in the sorting code that's calling the BufFileXXX routines.
> And I get 0 records selected.
And that's even more suggestive ;-)
This is going to be tough to debug if it takes a multi-gig database to
replicate. But if I'm guessing right about where the problem is, it
probably can be replicated on smaller tables if you use a smaller -S
(sort memory limit) setting when starting the backend. You can set -S
as small as 32 (kb), and having done that the bug might show up on tables
with a few hundred K of data. Would you try that and let me know?
The easiest way to experiment is to set -S on a per-backend basis
via the PGOPTIONS environment variable, eg
setenv PGOPTIONS "-S 32"
psql ...
The backend started for this psql session will set S=32 instead of
whatever the prevailing default is.
regards, tom lane
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To: pgsql-sql@postgresql.org
Cc: tgl@sss.pgh.pa.us, swheeler@sabre.com, pgsql-sql@hub.org
Subject: Re: [SQL] Questions about vacuum analyze
In-Reply-To: <28912.939305310@sss.pgh.pa.us>
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