On 09/14/2016 07:04 PM, Alan Pevec wrote:
Olso.db 4.13.3 did hit the scene about the time this showed up. So I
think we need to strongly consider blocking it and revisiting these
issues post newton.
So that means reverting all stable/newton changes, previous 4.13.x
have been already blocked https://review.openstack.org/365565
How would we proceed, do we need to revert all backport on stable/newton?
In case my previous email wasn't clear, I don't *yet* see evidence that
the recent 4.13.3 release of oslo.db is the cause of this problem.
However, that is only based upon what I see in this stack trace, which
is that the test framework is acting predictably (though erroneously)
based on the timeout condition which is occurring. I don't (yet) see a
reason that the same effect would not occur prior to 4.13.3 in the face
of a signal pre-empting the work of the pymysql driver mid-stream.
However, this assumes that the timeout condition itself is not a product
of the current oslo.db version and that is not known yet.
There's a list of questions that should all be answerable which could
assist in giving some hints towards this.
There's two parts to the error in the logs. There's the "timeout"
condition, then there is the bad reaction of the PyMySQL driver and the
test framework as a result of the operation being interrupted within the
test.
* Prior to oslo.db 4.13.3, did we ever see this "timeout" condition
occur? If so, was it also accompanied by the same "resource closed"
condition or did this second part of the condition only appear at 4.13.3?
* Did we see a similar "timeout" / "resource closed" combination prior
to 4.13.3, just with less frequency?
* Was the version of PyMySQL also recently upgraded (I'm assuming this
environment has been on PyMySQL for a long time at this point) ? What
was the version change if so? Especially if we previously saw "timeout"
but no "resource closed", perhaps an older version pf PyMySQL didn't
react in this way?
* Was the version of MySQL running in the CI environment changed? What
was the version change if so? Were there any configurational changes
such as transaction isolation, memory or process settings?
* Have there been changes to the "timeout" logic itself in the test
suite, e.g. whatever it is that sets up fixtures.Timeout()? Or some
change that alters how teardown of tests occurs when a test is
interrupted via this timeout?
* What is the magnitude of the "timeout" this fixture is using, is it on
the order of seconds, minutes, hours?
* If many minutes or hours, can the test suite be observed to be stuck
on this test? Has someone tried to run a "SHOW PROCESSLIST" while this
condition is occurring to see what SQL is pausing?
* Has there been some change such that the migration tests are running
against non-empty tables or tables with much more data than was present
before?
* Is this failure only present within the Nova test suite or has it been
observed in the test suites of other projects?
* Is this failure present only on the "database migration" test suite or
is it present in other opportunistic tests, for Nova and others?
* Have there been new database migrations added to Nova which are being
exercised here and may be involved?
I'm not sure how much of an inconvenience it is to downgrade oslo.db.
If downgrading it is feasible, that would at least be a way to eliminate
it as a possibility if these same failures continue to occur, or a way
to confirm its involvement if they disappear. But if downgrading is
disruptive then there are other things to look at in order to have a
better chance at predicting its involvement.
Cheers,
Alan
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