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Re: delete members in big groups with back_mdb

--On Wednesday, July 17, 2013 11:32 AM +0200 Marco Schirrmeister <marco@schirrmeister.net> wrote:

On Jul 17, 2013, at 1:08 AM, Howard Chu <hyc@symas.com> wrote:

Marco Schirrmeister wrote:

I have a problem with mdb and modify operations on very large groups.
Specifically deleting members from those groups. Removing 10 members
from a group with 25000 members takes 23 seconds. Which also means, all
other clients that want to do something hang. Deleting a user from
multiple big groups takes minutes before it finishes. Adding members to
a large group is quick though.

When this delete is running, the cpu goes also up to 100%.

It looks like it has to do with the index that I have on uniqueMember.
If I remove the index on uniqueMember, the delete of members in big
groups is fast.

System details are
CentOS 6 64bit
OpenLDAP 2.4.35
slapd.conf below

Is this something normal/exptected or is it maybe a bug?

Read slapd.conf(5) manpage, sortvals keyword.

Thanks for the hint Howard.
Deleting members from a big group on the test server is now fast with

Adding of members is a very little slower (20-30ms) compared to the
adding without sortvals. I will see how it goes on the production
environment with the real workload.

Personally, I prefer dynamic groups. You may wish to investigate those as well.



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