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Re: Huge number of disk writes after migration to 8.1

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: Marcin <migor(at)op(dot)pl>
Cc: pgsql-bugs(at)postgreSQL(dot)org
Subject: Re: Huge number of disk writes after migration to 8.1
Date: 2006-01-17 20:51:18
Message-ID: (view raw, whole thread or download thread mbox)
Lists: pgsql-bugspgsql-patches
Marcin <migor(at)op(dot)pl> writes:
> Attached you'll find the archive with data you've asked.

Well, breaking down the contents of the stats file I find:
	190 backends (218880 bytes)
	118 databases (8496 bytes)
	81952 tables (8523008 bytes)
And the ps listing shows there actually are about 190 live backends,
so the idea about leaked backend stats entries is clearly wrong.

The per-table data is 104 bytes/table, up from 80 in 8.0, so that's
a noticeable increase but hardly a killer.  What I have to conclude
is that 8.1 is tracking stats for a lot more tables than 8.0 was.
(Do you happen to have a number for the size of the stats file in
the 8.0 installation?  I don't need to see its contents, I just want
to know how big it is.)

Do you actually have 81952 tables in the installation?  Maybe we are
looking at a table-level leak.  Do you have autovacuum on where it was
not in 8.0?  Maybe that's causing it.

			regards, tom lane


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