Thread: Suspicious top output

Suspicious top output

From
Rafael Barrera Oro
Date:
Hello, i have a postgresql server running and from time to time it gets
painfully slow. When this happens i usually connect to the server and
run a "top" command, the output i get is filled with lines like the
following

71872 pgsql            1   4    0 48552K 42836K sbwait   1:41  4.79%
postgres

Are those connections that were not closed or something like that?

should i worry?

Thanks in advance, as always

yours trully

Rafael


Re: Suspicious top output

From
Ivan Voras
Date:
Rafael Barrera Oro wrote:
> Hello, i have a postgresql server running and from time to time it gets
> painfully slow. When this happens i usually connect to the server and
> run a "top" command, the output i get is filled with lines like the
> following
>
> 71872 pgsql            1   4    0 48552K 42836K sbwait   1:41  4.79%
> postgres
>
> Are those connections that were not closed or something like that?

This looks like FreeBSD; "sbwait" state is socket buffer wait, and
guessing from the CPU usage the process seems to be talking to another
process.

> should i worry?

Don't know. Are you sure all client processes disconnect properly from
the database?

Re: Suspicious top output

From
Greg Smith
Date:
On Tue, 22 Apr 2008, Rafael Barrera Oro wrote:

> Hello, i have a postgresql server running and from time to time it gets
> painfully slow.

The usual information you should always include when posting messages here
is PostgreSQL and operating system versions.

> When this happens i usually connect to the server and run a "top"
> command

The other thing you should fire up in another window is "vmstat 1" to
figure out just what's going on in general.  The great thing about those
is you can save them when you're done and easily analyze the results later
easily, which is trickier to do with top.

> 71872 pgsql            1   4    0 48552K 42836K sbwait   1:41  4.79%
> postgres

Some searching found this interesting suggestion from Darcy about things
stuck in sbwait:

http://unix.derkeiler.com/Mailing-Lists/FreeBSD/performance/2004-03/0015.html

--
* Greg Smith gsmith@gregsmith.com http://www.gregsmith.com Baltimore, MD