From: | Andres Freund <andres(at)anarazel(dot)de> |
---|---|
To: | Andreas Thiel <andreas(dot)thiel(at)u-blox(dot)com> |
Cc: | "pgsql-performance" <pgsql-performance(at)postgresql(dot)org> |
Subject: | Re: Large DB, several tuning questions: Index sizes, VACUUM, REINDEX, Autovacuum |
Date: | 2009-12-06 16:51:19 |
Message-ID: | 200912061751.20080.andres@anarazel.de |
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Lists: | pgsql-performance |
Hi Andreas,
Could you please properly quote the email? The way you did it is quite
unreadable because you always have to guess who wrote what.
On Sunday 06 December 2009 17:06:39 Andreas Thiel wrote:
> > I'm going to work on the table size of the largest table (result_orig)
> > itself by eliminating columns, stuffing n Booleans into bit(n)'s,
> > replacing double precision by reals, etc.. By this I should be able to
> > reduce the storage per row to ~1/3 of the bytes currently used.
> That sounds rather ambitous - did you factor in the per row overhead?
> I did now create the new table, I have now 63 instead of 94 bytes/row on
> average. So yes you're right I'm about to hit the bottom of the per row
> overhead.
How did you calculate that? Did you factor in the alignment requirements? The
ddl would be helpfull...
> Btw, have you possibly left over some old prepared transactions or an
> idle in
> transaction connection? Both can lead to sever bloat.
> For the former you can check the system table pg_prepared_xact for the
> latter
> pg_stat_activity.
> Seems no the case, pg_prepared_xact doesn't even exist.
Its pg_prepared_xacts (note the s), sorry my mind played me.
> Where would I find that postmaster output? In syslog? There's nothing
> visible...
Depends on your setup. I have not the slightest clue about centos. If
necessary start postmaster directly.
> > max_fsm_relations = 4194304 # min 100, ~70 bytes each
Have you corrected that value?
Andres
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