[Date Prev][Date Next] [Chronological] [Thread] [Top]

Re: What are the correct values for concurrency and threads for the ldbm backend ?

--On Thursday, April 28, 2005 6:37 PM +0200 Pantelis Petridis <pantelis.petridis@marconi.com> wrote:

Hello ,

I am using openldap 2.0.25.
The reason why I use such an old release is that until now we had no
reason to upgrade to a newer version.

For performance reasons I had to increase the parameters concurreny to 512
and threads to 384.
The ldap backend I use is ldbm. I have about 100000 entries and the
dabasesize is about  400MB.
I have a big hpux workstation with 4 processors and 4GB Ram.
I have to serve 160 read request per second (I can do that when I set
concurrency to 512 and threads to 384).

The slapd process consumes a lot of memory (more than 1GB) . I can not
understand why. The database
is only 400MB even if loaded in memory it is less than 1GB.

Does someone understand why the slapd process uses so much memory ?
Should I reduce concurrency and threads in the slapd.conf file ?

I will note that OpenLDAP 2.1 was a few hundred times faster than OpenLDAP 2.0, and that OpenLDAP 2.2 was about 50% faster than OpenLDAP 2.1. So if performance is your issue, I'd recommend upgrading.

Setting a large thread value is generally detrimental to performance. It takes careful experimentation, and I've never found anything over 30 to be of any good.


Quanah Gibson-Mount
Principal Software Developer
ITSS/Shared Services
Stanford University
GnuPG Public Key: http://www.stanford.edu/~quanah/pgp.html

"These censorship operations against schools and libraries are stronger
than ever in the present religio-political climate. They often focus on
fantasy and sf books, which foster that deadly enemy to bigotry and blind
faith, the imagination." -- Ursula K. Le Guin