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From
Date:
Everyone,

I had an odd situation occur this morning with PGSQL 7.4 run on Red Hat Enterprise 4 (update 3) and could really use
somewisdom.   

...  Single postmaster running.
...  vacuum full is run every night as part of a cron job
...  At start, data files consume about 28 GB
...  This morning I dropped the database and reloaded from current backup
... New instance consumes about 6 GB

I can only assume that the database was not compacted, but I thought vacuum full performed that function along with
tuplemaintenance.  Can anyone expound on the problem and suggest a solution other than dropping and reloading the
database?

Thanks in advance

Re:

From
Tom Lane
Date:
<mark.dingee@cox.net> writes:
> I had an odd situation occur this morning with PGSQL 7.4 run on Red Hat Enterprise 4 (update 3) and could really use
somewisdom.   

> ...  Single postmaster running.
> ...  vacuum full is run every night as part of a cron job
> ...  At start, data files consume about 28 GB
> ...  This morning I dropped the database and reloaded from current backup
> ... New instance consumes about 6 GB

> I can only assume that the database was not compacted, but I thought vacuum full performed that function along with
tuplemaintenance.  Can anyone expound on the problem and suggest a solution other than dropping and reloading the
database?

The evidence is mostly gone now, but what I'd suggest is waiting a while
to see if it bloats again, and if so finding out exactly *where* the
bloat is.  Make some notes now about the sizes of your tables and
indexes, and see what's getting larger.

My guess offhand is that the problem is index bloat.  VACUUM FULL not
only doesn't help much with that, it tends to make it worse.  If the
database size is supposed to be fairly stable, you'd probably be better
off with a maintenance regime that doesn't use VACUUM FULL but just
plain VACUUM.  Make sure your FSM settings are high enough.

            regards, tom lane

Re:

From
"Mark R. Dingee"
Date:
Tom,

Thanks for the advice.  I'll track it over the next couple weeks and see
what comes up.

Mark

On Tue, 2006-05-09 at 17:01 -0400, Tom Lane wrote:
> <mark.dingee@cox.net> writes:
> > I had an odd situation occur this morning with PGSQL 7.4 run on Red Hat Enterprise 4 (update 3) and could really
usesome wisdom.   
>
> > ...  Single postmaster running.
> > ...  vacuum full is run every night as part of a cron job
> > ...  At start, data files consume about 28 GB
> > ...  This morning I dropped the database and reloaded from current backup
> > ... New instance consumes about 6 GB
>
> > I can only assume that the database was not compacted, but I thought vacuum full performed that function along with
tuplemaintenance.  Can anyone expound on the problem and suggest a solution other than dropping and reloading the
database?
>
> The evidence is mostly gone now, but what I'd suggest is waiting a while
> to see if it bloats again, and if so finding out exactly *where* the
> bloat is.  Make some notes now about the sizes of your tables and
> indexes, and see what's getting larger.
>
> My guess offhand is that the problem is index bloat.  VACUUM FULL not
> only doesn't help much with that, it tends to make it worse.  If the
> database size is supposed to be fairly stable, you'd probably be better
> off with a maintenance regime that doesn't use VACUUM FULL but just
> plain VACUUM.  Make sure your FSM settings are high enough.
>
>             regards, tom lane