| From: | Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> |
|---|---|
| To: | Metin Doslu <metin(at)citusdata(dot)com> |
| Cc: | postgres performance list <pgsql-performance(at)postgresql(dot)org>, pgsql-hackers <pgsql-hackers(at)postgresql(dot)org>, Andres Freund <andres(at)2ndquadrant(dot)com>, Claudio Freire <klaussfreire(at)gmail(dot)com> |
| Subject: | Re: Parallel Select query performance and shared buffers |
| Date: | 2013-12-05 04:16:18 |
| Message-ID: | CAA4eK1+QTp3rcB_Mq7aWQ2wfBHstSRiUnK0Ouu6MbSX9W5OASA@mail.gmail.com |
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| Lists: | pgsql-hackers pgsql-performance |
On Wed, Dec 4, 2013 at 11:49 PM, Metin Doslu <metin(at)citusdata(dot)com> wrote:
> Here are some extra information:
>
> - When we increased NUM_BUFFER_PARTITIONS to 1024, this problem is
> disappeared for 8 core machines and come back with 16 core machines on
> Amazon EC2. Would it be related with PostgreSQL locking mechanism?
I think here there is a good chance of improvement with the patch
suggested by Andres in this thread, but
still i think it might not completely resolve the current problem as
there will be overhead of associating data
with shared buffers.
Currently NUM_BUFFER_PARTITIONS is fixed, so may be auto tuning it
based on some parameter's can
help such situations.
With Regards,
Amit Kapila.
EnterpriseDB: http://www.enterprisedb.com
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