[ovs-discuss] OVN Database sizes - Auto compact feature

[Daniel Alvarez Sanchez]

With OVS 2.8 branch it never shrank when I started to delete the ports since
the DB sizes didn't grow, which makes sense to me. The conditions weren't
met for further compaction.
See attached image.

NB:
2018-03-07T18:25:49.269Z|00009|ovsdb_file|INFO|/opt/stack/data/ovs/ovnnb_db.db:
compacting database online (647.317 seconds old, 436 transactions, 10505382
bytes)
2018-03-07T18:35:51.414Z|00012|ovsdb_file|INFO|/opt/stack/data/ovs/ovnnb_db.db:
compacting database online (602.089 seconds old, 431 transactions, 29551917
bytes)
2018-03-07T18:45:52.263Z|00015|ovsdb_file|INFO|/opt/stack/data/ovs/ovnnb_db.db:
compacting database online (600.563 seconds old, 463 transactions, 52843231
bytes)
2018-03-07T18:55:53.810Z|00016|ovsdb_file|INFO|/opt/stack/data/ovs/ovnnb_db.db:
compacting database online (601.128 seconds old, 365 transactions, 57618931
bytes)


SB:
2018-03-07T18:33:24.927Z|00009|ovsdb_file|INFO|/opt/stack/data/ovs/ovnsb_db.db:
compacting database online (1102.840 seconds old, 775 transactions,
10505486 bytes)
2018-03-07T18:43:27.569Z|00012|ovsdb_file|INFO|/opt/stack/data/ovs/ovnsb_db.db:
compacting database online (602.394 seconds old, 445 transactions, 15293972
bytes)
2018-03-07T18:53:31.664Z|00015|ovsdb_file|INFO|/opt/stack/data/ovs/ovnsb_db.db:
compacting database online (603.605 seconds old, 385 transactions, 19282371
bytes)
2018-03-07T19:03:42.116Z|00031|ovsdb_file|INFO|/opt/stack/data/ovs/ovnsb_db.db:
compacting database online (607.542 seconds old, 371 transactions, 23538784
bytes)




On Wed, Mar 7, 2018 at 7:18 PM, Daniel Alvarez Sanchez <dalvarez at redhat.com>
wrote:

> No worries, I just triggered the test now running OVS compiled out of
> 2.8 branch (2.8.3). I'll post the results and investigate too.
>
> I have just sent a patch to fix the timing issue we can see in the traces I
> posted. I applied it and it works, I believe it's good to fix as it gives
> us
> an idea of how frequent the compact is, and also to backport if you
> agree with it.
>
> Thanks!
>
> On Wed, Mar 7, 2018 at 7:13 PM, Ben Pfaff <blp at ovn.org> wrote:
>
>> OK, thanks.
>>
>> If this is a lot of trouble, let me know and I'll investigate directly
>> instead of on the basis of a suspected regression.
>>
>> On Wed, Mar 07, 2018 at 07:06:50PM +0100, Daniel Alvarez Sanchez wrote:
>> > All right, I'll repeat it with code in branch-2.8.
>> > Will post the results once the test finishes.
>> > Daniel
>> >
>> > On Wed, Mar 7, 2018 at 7:03 PM, Ben Pfaff <blp at ovn.org> wrote:
>> >
>> > > On Wed, Mar 07, 2018 at 05:53:15PM +0100, Daniel Alvarez Sanchez
>> wrote:
>> > > > Repeated the test with 1000 ports this time. See attached image.
>> > > > For some reason, the sizes grow while deleting the ports (the
>> > > > deletion task starts at around x=2500). The weird thing is why
>> > > > they keep growing and the online compact doesn't work as when
>> > > > I do it through ovs-appctl tool.
>> > > >
>> > > > I suspect this is a bug and eventually it will grow and grow unless
>> > > > we manually compact the db.
>> > >
>> > > Would you mind trying out an older ovsdb-server, for example the one
>> > > from OVS 2.8?  Some of the logic in ovsdb-server around compaction
>> > > changed in OVS 2.9, so it would be nice to know whether this was a
>> > > regression or an existing bug.
>> > >
>>
>
>
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