Re: Performance on 7.4 vs 7.2?

Pablo S wrote:

> Hi there Pg admins,
>
> I have 2 systems, one OLD,
> (linux 2.4 running postgresql-7.2.1-5 with a perl web db on
> Apache/1.3.23 mod_perl 1.26 and dbi 1.37 with peristent db connections
> via apache:dbi. )
>
> The other system is NEW
> (running the same web app on linux 2.6 postgresql-7.4.2-1 w/
> Apache/2.0.49 & mod_perl/1.99_12 & apache:dbi. fedora core 2)
>
> Both systems have almost identical hardware, and have had the same
> tweaks made to pg - at least all I can rack out of my brain –
>
> their SYSV shared mem increased to 128mb
> shared_buffers = 15200
> sort_mem = 32168
> effective_cache_size = 4000

I don't know what changes from 7.2 -> 7.4 but effective_cache_size
is too little IMO, or at least incongruous with sort_mem.
Try to rise that parameter to something more realistic.

Regards
Gaetano Mendola