Re: Performance Woes - Mailing list pgsql-performance

From Tom Lane
Subject Re: Performance Woes
Date
Msg-id 6685.1178771404@sss.pgh.pa.us
Whole thread Raw
In response to Re: Performance Woes  (Jeff Davis <pgsql@j-davis.com>)
List pgsql-performance
Jeff Davis <pgsql@j-davis.com> writes:
> On Wed, 2007-05-09 at 17:29 -0700, Joshua D. Drake wrote:
>> Sounds to me like you just need to up the total amount of open files
>> allowed by the operating system.

> It looks more like the opposite, here's the docs for
> max_files_per_process:

I think Josh has got the right advice.  The manual is just saying that
you can reduce max_files_per_process to avoid the failure, but it's not
making any promises about the performance penalty for doing that.
Apparently Ralph's app needs a working set of between 800 and 1000 open
files to have reasonable performance.

> That is a lot of tables. Maybe a different OS will handle it better?
> Maybe there's some way that you can use fewer connections and then the
> OS could still handle it?

Also, it might be worth rethinking the database structure to reduce the
number of tables.  But for a quick-fix, increasing the kernel limit
seems like the easiest answer.

            regards, tom lane

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