Re: CentOS - PostgreSQL 9.2.13 -> 9.4 - Mailing list pgsql-general

From Alvaro Herrera
Subject Re: CentOS - PostgreSQL 9.2.13 -> 9.4
Date
Msg-id 20150818163909.GG5232@alvherre.pgsql
Whole thread Raw
In response to Re: CentOS - PostgreSQL 9.2.13 -> 9.4  ("Joshua D. Drake" <jd@commandprompt.com>)
Responses Re: CentOS - PostgreSQL 9.2.13 -> 9.4
Re: CentOS - PostgreSQL 9.2.13 -> 9.4
Re: CentOS - PostgreSQL 9.2.13 -> 9.4
List pgsql-general
Joshua D. Drake wrote:
>
> On 08/18/2015 09:19 AM, Melvin Davidson wrote:
> >>8 x 16GB 1600MHz PC3-12800 DDR3                 - 128GB total
> > >>shared_buffers=60GB
> >
> >I would say 60GB is too high when you have 128GB system memory.
> >Try lowering it to shared_buffers=32GB and let the O/S handle more of
> >the work.
>
> I would also look at see if you are checkpointing either via segment
> rollover or time.

If it works fine under 9.2, why would it be a problem in 9.3 and 9.4?
Keep in mind the question is not "let's make this as fast as possible"
but rather "let's make this on par with 9.2".

One thing to look at is the rate of WAL generation for a set number of
transactions.  Maybe the later releases are generating more WAL due to
multixacts, for instance (prior to 9.3 these weren't wal-logged.)

--
Álvaro Herrera                http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services


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