WiredTiger is *much* slower at creating and dropping indexes and collections. I haven't worked out why that is, other than doing some stracing and seeing that a lot of time is spent in fdatasync - I haven't dug into the mongo source code. There's a bit more detail in these bugs: https://bugs.launchpad.net/juju-core/+bug/1573294 https://jira.mongodb.org/browse/SERVER-21198
I've changed the tests so that instead of dropping and recreating databases in teardown and setup we clear out all of the collections (except the transaction collections) between tests. Obviously that's worse from the perspective of test isolation, but it seems to work well - better than I was expecting, to be honest. Cheers, Christian On Wed, May 18, 2016 at 9:58 AM roger peppe <roger.pe...@canonical.com> wrote: > Out of interest, what's causing the 3.2 slowdown and what's the hack to > speed it up again? > On 18 May 2016 09:51, "Christian Muirhead" < > christian.muirh...@canonical.com> wrote: > >> >> >> On Wed, May 18, 2016 at 2:04 AM David Cheney <david.che...@canonical.com> >> wrote: >> >>> 100x more webscale >>> >> Ha! >> >> I'm *just about* finished the hack to make the state tests on 3.2 run in >> about the same time as on 2.4. On my machine the state tests take 6m24s on >> 3.2 and the old version took 4m56s. Which is still worse, unfortunately, >> but at least it isn't 100x worse. So if there are stability benefits to >> running the tests on 3.2 it's still a win, I guess? >> >> >> >>> >>> On Wed, May 18, 2016 at 11:02 AM, Horacio Duran >>> <horacio.du...@canonical.com> wrote: >>> > For now we are trying to go around mongo issues that make the tests >>> 100x >>> > slower (yes one hundred) once this is fixed we should start using >>> mongo 3.2 >>> > exclusively since 2.4 iirc is EOL or near. The issue lies in the new >>> storage >>> > engine, which we could skip if mmapv1 ( the old one) wasn't also >>> nearing EOL >>> > I am currently on the phone but if You want more details I can dig up >>> the >>> > bug with details of what I am talking about. >>> > >>> > >>> > On Tuesday, 17 May 2016, David Cheney <david.che...@canonical.com> >>> wrote: >>> >> >>> >> What's the plan for mongo 3.2 ? Will we be required to support 2.x >>> >> versions for the foreseeable future, or is there a possibility to make >>> >> it a build or run time failure if mongo < 3.2 is installed on the host >>> >> ? >>> >> >>> >> On Wed, May 18, 2016 at 9:01 AM, Martin Packman >>> >> <martin.pack...@canonical.com> wrote: >>> >> > On 17/05/2016, Curtis Hovey-Canonical <cur...@canonical.com> wrote: >>> >> >> >>> >> >> The juju-mongo2.6 package will be be preferred by juju 1.2.5 in >>> xenial >>> >> >> and without other changes, 2.4 will be used by all other 1.25 >>> series. >>> >> > >>> >> > This isn't yet true, there's a bug open for it: >>> >> > >>> >> > "Use juju-mongodb2.6 for 1.25 on xenial" >>> >> > <https://bugs.launchpad.net/ubuntu/+source/juju-core/+bug/1570650> >>> >> > >>> >> > I had made the packaging change, but without juju code changes as >>> well >>> >> > it just went and installed the old (2.4) juju-mongodb anyway when >>> >> > setting up a state server. >>> >> > >>> >> > Martin >>> >> > >>> >> > -- >>> >> > Juju-dev mailing list >>> >> > Juju-dev@lists.ubuntu.com >>> >> > Modify settings or unsubscribe at: >>> >> > https://lists.ubuntu.com/mailman/listinfo/juju-dev >>> >> >>> >> -- >>> >> Juju-dev mailing list >>> >> Juju-dev@lists.ubuntu.com >>> >> Modify settings or unsubscribe at: >>> >> https://lists.ubuntu.com/mailman/listinfo/juju-dev >>> >>> -- >>> Juju-dev mailing list >>> Juju-dev@lists.ubuntu.com >>> Modify settings or unsubscribe at: >>> https://lists.ubuntu.com/mailman/listinfo/juju-dev >>> >> >> -- >> Juju-dev mailing list >> Juju-dev@lists.ubuntu.com >> Modify settings or unsubscribe at: >> https://lists.ubuntu.com/mailman/listinfo/juju-dev >> >>
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