From: Alexy Khrabrov <deliverable@gmail.com>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Scott Marlowe <scott.marlowe@gmail.com>
Cc: pgsql-performance@postgresql.org
Subject: Re: two memory-consuming postgres processes
Date: Fri, 2 May 2008 13:26:47 -0700
Message-ID: <72E02D29-848B-467A-AE6B-401568010254@gmail.com> (raw)
In-Reply-To: <21403.1209759217@sss.pgh.pa.us>
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<27A4D379-2553-496D-A96C-102F2A5E62C2@gmail.com>
<dcc563d10805021253n1589baa7u559fdfc8053d23d3@mail.gmail.com>
<21403.1209759217@sss.pgh.pa.us>
On May 2, 2008, at 1:13 PM, Tom Lane wrote:
> I don't think you should figure on more than 1GB being
> usefully available to Postgres, and you can't give all or even most of
> that space to shared_buffers.
So how should I divide say a 512 MB between shared_buffers and, um,
what else? (new to pg tuning :)
I naively thought that if I have a 100,000,000 row table, of the form
(integer,integer,smallint,date), and add a real coumn to it, it will
scroll through the memory reasonably fast. Yet when I had
shared_buffers=128 MB, it was hanging there 8 hours before I killed
it, and now with 1500MB is paging again for several hours with no end
in sight. Why can't it just add a column to a row at a time and be
done with it soon enough? :) It takes inordinately long compared to a
FORTRAN or even python program and there's no index usage for this
table, a sequential scan, why all the paging?
Cheers,
Alexy
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To: pgsql-performance@postgresql.org
Cc: deliverable@gmail.com, tgl@sss.pgh.pa.us, scott.marlowe@gmail.com
Subject: Re: two memory-consuming postgres processes
In-Reply-To: <72E02D29-848B-467A-AE6B-401568010254@gmail.com>
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