That's sounds good.

BTW it would be nice to be able to see a compaction and the duration
of the compaction. Is this possible with raising the log level maybe?

Is there a way to trigger somehow a writing connection from
ovsdb-server to southdb for debugging/testing purposes? With a trivial
operation or network command (cli) may be?

Kind regards,

Christian Stelter

On Fri, Apr 8, 2022 at 11:54 PM Frode Nordahl
<[email protected]> wrote:
>
>
>
> fre. 8. apr. 2022, 14:41 skrev Christian Stelter <[email protected]>:
>>
>> Hi!
>>
>> We are experiencing high latencies from time to time in one of our
>> openstack environments.  While looking into the issue we found that
>> the southdb has frequent leader changes.
>>
>> We are running the Xena release and ovsdb-server (Open vSwitch) 2.16.0
>> deployed via kolla-ansible.
>>
>>
>> We also noticed that the leader changes are caused by snapshots
>> (database compaction?).
>
>
> Since this commit [0] introduced in OVS 2.16, transfer of leadership before 
> snapshot is the intended behaviour. Before the change the leader would stop 
> processing requests until the snapshot completed.
>
>> Do these changes/snapshots have an impact on the performance of the southdb?
>>
>> Is there anything to improve the performance in case of leadership changes?
>
>
> Until this patch [1], Neutron would require a connection to the leader for 
> all threads talking to the SB DB. That lead to unesecary reconnection on 
> leader change, which may be the source of the issues you see. Try it out and 
> see if it helps.
>
> 0: 
> https://github.com/openvswitch/ovs/commit/3c2d6274bceecb65ec8f2f93f2aac26897a7ddfe
> 1: https://review.opendev.org/q/I7442170d015f195a5430e71567fbc7d67b81d385
>
> --
> Frode Nordahl
>
>
>> Kind regards,
>>
>> Christian Stelter
>> _______________________________________________
>> discuss mailing list
>> [email protected]
>> https://mail.openvswitch.org/mailman/listinfo/ovs-discuss
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