Re: BUG #6650: CPU system time utilization rising few times a day

On Fri, May 18, 2012 at 5:09 AM, <a(dot)krawiec(at)focustelecom(dot)pl> wrote:
> The following bug has been logged on the website:
>
> Bug reference:      6650
> Logged by:          Andrzej Krawiec
> Email address:      a(dot)krawiec(at)focustelecom(dot)pl
> PostgreSQL version: 8.4.11
> Operating system:   CentOS 6.0 - 2.6.32-220.13.1.el6.x86_64
> Description:
>
> Primarily checked on PG 8.4.9 (same OS), problem also occurs. Few times a
> day I get a situation where PostgreSQL stops running for 1-2 minutes. CPU is
> running 99% in systime. IO is OK, only interrupts are extremely high (over
> 100k). System operates on 2 x Xeon 10 Core, 128 GB RAM, raid 10. Does anyone
> have any idea?

Try using strace to figure out where all that system time is going.
Sometimes the '-c' option is helpful.

It might also be helpful to connect gdb to the process and get a
backtrace, then continue, stop it again, get another backtrace.
Repeat that a few times and send us the backtrace that occurs most
frequently.

Is it a regular backend that is eating all that CPU time, or an
autovacuum worker?

--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company