Re: pg_prewarm

Hi,

On Thu, 2012-03-08 at 23:13 -0500, Robert Haas wrote:
> It's been bugging me for a while now that we don't have a prewarming
> utility, for a couple of reasons, including:
>
> 1. Our customers look at me funny when I suggest that they use
> pg_relation_filepath() and /bin/dd for this purpose.
>
> 2. Sometimes when I'm benchmarking stuff, I want to get all the data
> cached in shared_buffers. This is surprisingly hard to do if the size
> of any relation involved is >=1/4 of shared buffers, because the
> BAS_BULKREAD stuff kicks in. You can do it by repeatedly seq-scanning
> the relation - eventually all the blocks trickle in - but it takes a
> long time, and that's annoying.
>
> So I wrote a prewarming utility.

I was talking to an Oracle DBA about this just yesterday. We also have
pgfincore, but pg_prewarm is pretty much we need actually, I think. Did
not test the patch, but the feature should be in core/contrib/whatever.
This will also increase performance for the static tables that needs to
be in the buffers all the time. I'm also seeing some use cases for BI
databases.

Thanks!

Regards,
--
Devrim GÜNDÜZ
Principal Systems Engineer @ EnterpriseDB: http://www.enterprisedb.com
PostgreSQL Danışmanı/Consultant, Red Hat Certified Engineer
Community: devrim~PostgreSQL.org, devrim.gunduz~linux.org.tr
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