Re: slow server : s_lock and _bt_checkkeys on perf top

On Wed, Mar 4, 2015 at 1:31 PM, Soni M <diptatapa@gmail.com> wrote:
> Hello All,
>
> Master db size 1.5 TB
> All postgres 9.1.13 installed from RHEL package.
> It has streaming replica and slony replica to another servers.
>
> Server performance is slower than usual, before that, there's a big query
> got cancelled and then performance get slow.
>
> No sign of IO wait.
>
> on sar, it's %user and %system dominate the cpu usage
> 01:25:04 PM     CPU     %user     %nice   %system   %iowait    %steal
> %idle
> Average:        all     51.91      0.00     12.03      0.66      0.00
> 35.39
>
> on perf top, i saw
>  18.93%  postgres                                  [.] s_lock
>  10.72%  postgres                                  [.] _bt_checkkeys
> almost always at top.
>
> I don't have any idea, what's causing it or how to resolve it ?

Can you post the entire 'perf top'?  do you see (specifically I'm
wondering if you are bumping against the RecoveryInProgress s_lock
issue).  If so, upgrading postgres might be the best way to resolve
the issue.

merlin