Re: delete members in big groups with back_mdb

[Quanah Gibson-Mount <quanah@zimbra.com>]

--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:
> > > 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.

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

--Quanah



--

Quanah Gibson-Mount
Lead Engineer
Zimbra, Inc
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