Re: Question about memory allocations - Mailing list pgsql-performance

From Steve
Subject Re: Question about memory allocations
Date
Msg-id Pine.GSO.4.64.0704122355360.17955@kittyhawk.tanabi.org
Whole thread Raw
In response to Re: Question about memory allocations  (Greg Smith <gsmith@gregsmith.com>)
List pgsql-performance
> I didn't notice anyone address this for you yet.  There is a tool in
> contrib/pg_buffercache whose purpose in life is to show you what the shared
> buffer cache has inside it.  The documentation in that directory leads
> through installing it.  The additional variable you'll likely never know is
> what additional information is inside the operating system's buffer cache.

     Okay -- thanks!  I'll take a look at this.

>> # Leaving this low makes the DB complain, but I'm not sure what's #
>> reasonable.
>> checkpoint_segments = 128
>
> That's a reasonable setting for a large server.  The main downside to setting
> it that high is longer recovery periods after a crash, but I doubt that's a
> problem for you if you're so brazen as to turn off fsync.

     Hahaha yeah.  It's 100% assumed that if something goes bad we're
restoring from the previous day's backup.  However because the DB is read
only for -most- of the day and only read/write at night it's acceptable
risk for us anyway.  But good to know that's a reasonable value.


Steve

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