Re: Very Bad Performance.

Well, it's not quite that simple

the rule of thumb is 6-10% of available memory before postgres loads is
allocated to shared_buffers.
then effective cache is set to the SUM of shared_buffers + kernel buffers

Then you have to look at individual slow queries to determine why they
are slow, fortunately you are running 7.4 so you can set
log_min_duration to some number like 1000ms and then
try to analyze why those queries are slow.

Also hyperthreading may not be helping you..

Dave

Pallav Kalva wrote:

> Hi ,
>
>     I am experiencing a very bad performance on my production database
> lately , all my queries are slowing down. Our application is a
> webbased system with lot of selects and updates. I am running
> "vacuumdb" daily on all the databases, are the below postgres
> configuration parameters are set properly ? can anyone take a look.
> Let me know if you need anymore information.
>
>
> Postgres Version: 7.4
> Operating System: Linux Red Hat 9
> Cpus: 2 Hyperthreaded
> RAM: 4 gb
> Postgres Settings:
> max_fsm_pages             | 20000
> max_fsm_relations         | 1000
> shared_buffers               | 65536
> sort_mem                       | 16384
> vacuum_mem                | 32768
> wal_buffers                    | 64
> effective_cache_size      | 393216
>
> Thanks!
> Pallav
>
>
> ---------------------------(end of broadcast)---------------------------
> TIP 4: Don't 'kill -9' the postmaster
>
>

--
Dave Cramer
http://www.postgresintl.com
519 939 0336
ICQ#14675561