Re: Lock is no longer valid / deferring operation

["Gavin Henry" <ghenry@suretecsystems.com>]

<quote who="Toby Blake">
> Hi all,

Hi Toby.

> For largely historical reasons we run slapd servers on most clients
> (this will probably change in the future - I'm just giving this
> information as background).

Why?

>  We're seeing problems when some of these
> machines are busy, particularly, it seems, with memory intensive
> activity, although it's hard to substantiate as I generally only see
> the machines after they've broken.  It's annoying as I can't reproduce
> these problems.

It's going to be hard to pin point then ;-) How much memory/CPU etc. do
these clients have and what other services do they provide?

>
> We see quite a few problems with slapd getting into a state where it's
> deferring operations, for whatever reason - I think I understand these
> - these are when slapd basically says sorry, I'm too busy doing X, so
> I'll defer Y until I have time.  Is this accurate?

Yes. What kind of clients are searching/binding to them? Local?

>
> The second case I'm also seeing is bdb complaining about locks being
> no longer valid, e.g.
>
> slapd[3780]: bdb(dc=inf,dc=ed,dc=ac,dc=uk): DB_LOCK->lock_put: Lock is no
> longer valid
>
> slapd seems to keep going for the time being until getting into a
> state where it defers all binding operations and goes into some kind
> of spin where it sits at 99% cpu and has to be killed with a -9.

Is everything local? Nothing mounted locally, like NFS for the directory
data.

>
> I suppose I have a couple of questions about the "Lock is no longer
> valid" error....
>
> - What causes it?
> - Is it something I can prevent by configuration changes (for
>    instance, would increasing the numbers of locks, lockers and objects
>    help?)

One for the dev team. I do know this is an error message from Berkeley DB
by grepping the source.

>
> We're running openldap 2.3.35 with ITS#4924 and ITS#4925 patches with
> a bdb backend running 4.2.52 with all 6 recommended patches.

I hope you mean 5, as there are only 5 listed on the Oracle site.

>
> The only DBCONFIG settings we currently have are:
>
> dbconfig      set_cachesize 0 67108864 1
> dbconfig      set_lg_regionmax 262144
> dbconfig      set_lg_bsize 2097152

I take it dbconfig is a keyword you've added for this example, as it's not
valid.

>
> Thanks in advance
> Toby Blake
> School of Informatics
> University of Edinburgh
>