Thread: High Processor consumption

High Processor consumption

From
Benjamin Bostow
Date:
I am running RH 7.3 running Apache 1.3.27-2 and PostgreSQL 7.2.3-5.73.
When having 100+ users connected to my server I notice that postmaster
consumes up wards of 90% of the processor and I hardly am higher than
10% idle. I did notice that when I kill apache and postmaster that my
idle processor percentage goes to 95% or higher. I am looking on ways
that I can find what connections are making the database processes run
so high. If this could also tell which program is accessing it, it would
be helpful. I have look through the documents on performance tuning
postgresql and have adjusted my memory with little effect. I have even
routed all traffic away from the Apache server so no load is on apache.
I do have C programs that run and access the database. Any help will be
greatly appreciated.

Thanks in advance,
Ben




Re: High Processor consumption

From
Shridhar Daithankar
Date:
Benjamin Bostow wrote:

> I am running RH 7.3 running Apache 1.3.27-2 and PostgreSQL 7.2.3-5.73.
> When having 100+ users connected to my server I notice that postmaster
> consumes up wards of 90% of the processor and I hardly am higher than
> 10% idle. I did notice that when I kill apache and postmaster that my
> idle processor percentage goes to 95% or higher. I am looking on ways
> that I can find what connections are making the database processes run
> so high. If this could also tell which program is accessing it, it would
> be helpful. I have look through the documents on performance tuning
> postgresql and have adjusted my memory with little effect. I have even
> routed all traffic away from the Apache server so no load is on apache.
> I do have C programs that run and access the database. Any help will be
> greatly appreciated.

Routinely the CPU load for postgresql translates to too much low shared buffers
setting for requirement.

What are your postgresql.conf tunings? Could you please post them?

  Shridhar


Re: High Processor consumption

From
Shridhar Daithankar
Date:
Benjamin Bostow wrote:

> I haven't modified any of the setting. I did try changing shmmax from
> 32MB to 256MB but didn't see much change in the processor usage. The
> init script that runs to start the server uses the following:
> su -l postgres -s /bin/sh -c "/usr/bin/pg_ctl  -D $PGDATA -p
> /usr/bin/postmaster -o \"-i -N 128 -B 256\" start  > /dev/null 2>&1" <
> /dev/null

Lol.. -B 256 does not mean 256MB of buffers. It means 2MB of buffers. Each
buffer is of 8K. Try upping it to a 1000 or 2000
>
> I haven't modified postgresql.conf yet but am going through a book on
> performance tuning the server. If you can provide any suggestions or
> help as I am new to postgres it would be appreciated.

http://www.varlena.com/varlena/GeneralBits/Tidbits/perf.html

  HTH

  Shridhar