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From: Rafael Domiciano <rafael.domiciano@gmail.com>
To: Kevin Neufeld <kneufeld@refractions.net>
Cc: pgsql-admin@postgresql.org
Subject: Re: Configuring Shared Buffers
Date: Tue, 1 Jul 2008 22:24:49 -0300
Message-ID: <3a0028490807011824h3da9d7begeb8a8d31f3fe7366@mail.gmail.com> (raw)
In-Reply-To: <486999BF.9030306@refractions.net>
References: <3a0028490806301052y193a4aeayfcc6deafdeb1cdb2@mail.gmail.com>
<20080630182830.GA5358@easy2.in-chemnitz.de>
<3a0028490806301201m5e4c48d4qc51a880b8f80ecf5@mail.gmail.com>
<20080701010927.GH18252@alvh.no-ip.org>
<486999BF.9030306@refractions.net>
Yes, I was talking about 100 max connections...
I am doing some benchmarks tests with diferent configurations...
I'll try what you said Kevin.
Thank you All
2008/6/30 Kevin Neufeld <kneufeld@refractions.net>:
> I agree. I have a similar system that I use for development purposes and
> have the shared_buffers sitting comfortable around 1GB. On production
> systems with 16GB of RAM, I've seen this as high as 12GB. There is talk
> nowadays, however, that this setting could drop back down to defaults on
> modern installations and let the OS handle cached memory as it sees fit.
> In any case, the biggest performance gain I see for you would be setting
> work_mem appropriately. This is the memory postgres is permitted to use for
> sorts, merges, hash joins, etc. before being forced to disk. It defaults
> to 1MB. In my opinion, this is far too low. This is the memory allocated
> to each sort/hash/etc operation. So for a complicated query, postgres could
> use several allocations. Even though, I think you could raise this
> considerably. If your system is a dedicated postgres box, I would take the
> total memory, subtract that needed for the OS, subtract what you decided to
> use for shared_buffers, and divide the rest by your 100 connections. So,
> for you, I see this around 30MB. On my development box with only a few
> connections, I have this around 500MB and sometime spike it to 1.2GB on the
> fly before a long running query.
>
> Cheers,
> Kevin
>
> Alvaro Herrera wrote:
>
>> Rafael Domiciano escribió:
>>
>>
>>> The Postgres version is 8.3.3 and I am using Fedora Core 8.
>>> I have in the actual server around 70 connections the same time. I am
>>> assigning for this 100.
>>>
>>>
>>
>> 100 MB? That's not very much either. You can probably get a hefty
>> performance boost by upping it a lot more (depending on whether the
>> machine is doing something else, or Postgres is the only service running
>> on it.)
>>
>>
>>
>>
>
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