Search Postgresql Archives

Re: How to speed up the first-time-searching in pgsql?

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On Tue, May 26, 2009 at 7:43 PM, Tom Lane <tgl@xxxxxxxxxxxxx> wrote:
> Greg Smith <gsmith@xxxxxxxxxxxxx> writes:
>> On Tue, 26 May 2009, Scott Marlowe wrote:
>>> Also, in the morning, have a cron job crank up that does "select * from
>>> mybigtable" for each big table to load it into cache.
>
>> Just to clarify:  on 8.3 and later versions, doing this doesn't do what
>> some people expect.  Sequential scans like that will continuously re-use a
>> 256KB section of the PostgreSQL shared_buffers space, so this won't cause
>> all of that to get paged back in if the problem is related to it being
>> swapped out.  It will pass everything through the OS buffer cache though
>> and prime it usefully, which might be all that's actually needed.
>
> Bearing in mind that this is a Windows server ... I seem to recall that
> the conventional wisdom is still to keep shared_buffers relatively small
> on Windows.  So priming the OS cache is exactly what it's about.
> (Keeping that down should also help avoid the other scenario Scott was
> worried about, where shared memory itself gets paged out.)

Yeah, I thought it was pretty obvious I was talking OS cache up there.

-- 
Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-general


[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[Index of Archives]     [Postgresql Jobs]     [Postgresql Admin]     [Postgresql Performance]     [Linux Clusters]     [PHP Home]     [PHP on Windows]     [Kernel Newbies]     [PHP Classes]     [PHP Books]     [PHP Databases]     [Postgresql & PHP]     [Yosemite]
  Powered by Linux