Re: How to avoid vacuuming a huge logging table - Mailing list pgsql-performance

From Greg Sabino Mullane
Subject Re: How to avoid vacuuming a huge logging table
Date
Msg-id ddcb039d012ec533c0cb330b5754b579@biglumber.com
Whole thread Raw
In response to How to avoid vacuuming a huge logging table  (Mark Stosberg <mark@summersault.com>)
List pgsql-performance
-----BEGIN PGP SIGNED MESSAGE-----
Hash: RIPEMD160


> Take a really different approach. Log in CSV format to text files
> instead, And only import the date ranges we need "on demand" if a report
> is requested on the data.

Seems like more work than a separate database to me. :)

> 2. We could find a way to exclude the table for vacuuming, and let it
> grow even larger. Putting the table in it's own database would
> accomplish that, but it would nice to avoid the overhead of a second
> database connection.

Specific exclusions is generally what I've done for similar problems in
the past. If you can live without the per-database summary at the end of
the vacuum, you can do something like this:

SET search_path = 'pg_catalog';
SELECT set_config('search_path',
  current_setting('search_path')||','||quote_ident(nspname),'false')
  FROM pg_namespace
  WHERE nspname <> 'pg_catalog'
  ORDER BY 1;

\t
\o pop
SELECT 'vacuum verbose analyze '||quote_ident(relname)||';'
  FROM pg_class
  WHERE relkind = 'r'
  AND relname <> 'ginormous_table'
  ORDER BY 1;
\o
\i pop

Or put any tables you don't want vacuumed by this script into their own schema:

...
SELECT 'vacuum verbose analyze '||quote_ident(relname)||';'
  FROM pg_class c, pg_namespace n
  WHERE relkind = 'r'
  AND relnamespace = n.oid
  AND nspname = 'novac'
  ORDER BY 1;
...

Just flip the equality operator, and you've got a way to vacuum just those
excluded tables, for example once a week during a slow time.


- --
Greg Sabino Mullane greg@turnstep.com
End Point Corporation
PGP Key: 0x14964AC8 200702211402
http://biglumber.com/x/web?pk=2529DF6AB8F79407E94445B4BC9B906714964AC8
-----BEGIN PGP SIGNATURE-----

iD8DBQFF3JeivJuQZxSWSsgRA7LZAKC7Sfz4XBTAfHuk1CpR+eBl7ixBIACeML8N
1W2sLLI4HMtdyV4EOoh2XkY=
=eTUi
-----END PGP SIGNATURE-----



pgsql-performance by date:

Previous
From: Alvaro Herrera
Date:
Subject: Re: Auto-Vacuum in 8.1 was ineffective for me. 8.2 may work better?
Next
From: Dimitri Fontaine
Date:
Subject: Re: Postgres performance Linux vs FreeBSD