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

Ben Pfaff blp at ovn.org
Wed Mar 7 20:50:42 UTC 2018


OK.

I guess we need to investigate this issue from the basics.

On Wed, Mar 07, 2018 at 09:02:02PM +0100, Daniel Alvarez Sanchez wrote:
> 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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