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Old 04-19-2008, 08:48 AM
Tom Lane
 
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Default Re: Defining performance.

Paul Lathrop <plathrop@squaretrade.com> writes:
> ... When I joined the company last year, the databases were
> deployed on 12-disk RAID5 arrays on dual-proc AMD machines with 4Gb of
> RAM, running Debian Woody and Postgres 7.2. These systems seemed to
> suffer a gradually decreasing performance accompanied by a gradually
> growing disk space usage. The DBA had come to the conclusion that the
> VACUUM command did/does not work on these systems, because even after a
> VACUUM FULL, the size of the database was continually increasing.


The very first thing you need to do is get off 7.2.

After that, I'd recommend looking at *not* using VACUUM FULL. FULL is
actually counterproductive in a lot of scenarios, because it shrinks the
tables at the price of bloating the indexes. And 7.2's poor ability to
reuse index space turns that into a double whammy. Have you checked
into the relative sizes of tables and indexes and tracked the trend over
time?

regards, tom lane

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