Re: delete members in big groups with back_mdb

[Marco Schirrmeister <marco@schirrmeister.net>]

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

> Marco Schirrmeister wrote:
>> Hi,
>> 
>> 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 sortvals.

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.


Thanks again
Marco