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Re: RE24 (2.4.15) slapd consuming large amounts of CPU

--On Wednesday, March 04, 2009 1:55 PM -0500 John Morrissey <jwm@horde.net> wrote:

I upgraded one of our consumers to 2.4.15 recently, from RE24 as of
20090113. Its configuration stayed the same, save for bumping the BDB
cache size from 256MB to 2GB.

After a few hours of uptime, slapd suddenly begins consuming enormous
amounts of CPU (a three- to four-fold increase over less than a few
minutes, and is sustained until slapd is restarted).

A backtrace (below) shows many threads waiting on a mutex in

This is with BDB 4.7 (with all patches applied) on Debian lenny.
'db_stat -c' output is below (and looks sane), in case that's useful.
Thinking thread contention, I bumped the worker thread count (slapd.conf
threads directive) down from 32 to 8, which has made no difference.

Interseting. I've seen this sort of CPU usage issue with OpenLDAP 2.3/BDB4.2.52 on Ubuntu 8. Do you know how BDB 4.7 was built? I.e., specifically, did it have the:

--enable-posixmutexes --with-mutex=POSIX/pthreads

options enabled?

Also, are you using a shared memory key? I've found that has a significant (positive) impact with BDB 4.7 on linux boxes.



Quanah Gibson-Mount
Principal Software Engineer
Zimbra, Inc
Zimbra ::  the leader in open source messaging and collaboration