Re: Now I am back, next thing. Final PGS tuning.

On Wed, Apr 8, 2009 at 5:38 PM, Massa, Harald Armin <chef(at)ghum(dot)de> wrote:

> Bill, Jennifer,
>
> > *shared_buffers = 1024 # min 128kB or max_connections*16kB ## Also to
>> low.
>> > Right? I've got 3GB to work with!*
>>
>> Assuming that's equating to 1G, then the value is about right. Common
>> best practice is to set this value to 1/4 - 1/3 of the memory available
>> for PostgreSQL. You're saying you'll have ~3G for PG, so 1G is about
>> right to start with.
>>
>>
> "documenting" that for the wiki is still on my backlog; so, here:
>
> shared_buffers of PostgreSQL on Windows != shared_buffers of PostgreSQL on
> Unix
>
> My experience is that raising shared_memory on Windows above minimum+~20%
> is not helping performance; it's more effective to have that memory at
> Windows for caching. (at least up to server 2003)

I forgot to comment on this on Bill so its good you brought it up again.
This guide : http://wiki.postgresql.org/wiki/Tuning_Your_PostgreSQL_Server
says under shared_buffers
**
*"If you have a system with 1GB or more of RAM, a reasonable starting value
for shared_buffers is 1/4 of the memory in your system."*
**
*in your system* ... that means I should count from 8GB right? Bill
mentioned countring from the 3GB. What would you say Harald, is perhaps 1.5
GB more suitable, a comprise for my giga byte greed :P haha!

>
>
> Harald
>
> --
> GHUM Harald Massa
> persuadere et programmare
> Harald Armin Massa
> Spielberger Straße 49
> 70435 Stuttgart
> 0173/9409607
> no fx, no carrier pigeon
> -
> LASIK good, steroids bad?
>
When it comes to the effective_cache I think this might be of great
importance for me since similar tuples will be fetched quite often by
different users. So caching could become quite important here. 439 MB is not
so much. The same guide as mentioned seconds ago says this :
*Setting effective_cache_size to 1/2 of total memory would be a normal
conservative setting, and 3/4 of memory is a more aggressive but still
reasonable amount.*
**
3/4 of total memory!? Its on 439 MB now. Could someone give me a better
offer?
Other things to consider ?
Sincerely / Jennifer