Re: Recording test runtimes with the buildfarm

On 6/11/20 10:21 AM, Stephen Frost wrote:
> Greetings,
>
> * David Rowley (dgrowleyml(at)gmail(dot)com) wrote:
>> On Thu, 11 Jun 2020 at 10:02, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>>> Thomas Munro <thomas(dot)munro(at)gmail(dot)com> writes:
>>>> I've been doing that in a little database that pulls down the results
>>>> and analyses them with primitive regexes. First I wanted to know the
>>>> pass/fail history for each individual regression, isolation and TAP
>>>> script, then I wanted to build something that could identify tests
>>>> that are 'flapping', and work out when the started and stopped
>>>> flapping etc. I soon realised it was all too noisy, but then I
>>>> figured that I could fix that by detecting crashes. So I classify
>>>> every top level build farm run as SUCCESS, FAILURE or CRASH. If the
>>>> top level run was CRASH, than I can disregard the individual per
>>>> script results, because they're all BS.
>>> If you can pin the crash on a particular test script, it'd be useful
>>> to track that as a kind of failure. In general, though, both crashes
>>> and non-crash failures tend to cause collateral damage to later test
>>> scripts --- if you can't filter that out then the later scripts will
>>> have high false-positive rates.
>> I guess the fact that you've both needed to do analysis on individual
>> tests shows that there might be a call for this beyond just recording
>> the test's runtime.
>>
>> If we had a table that stored the individual test details, pass/fail
>> and just stored the timing information along with that, then, even if
>> the timing was unstable, it could still be useful for some analysis.
>> I'd be happy enough even if that was only available as a csv file
>> download. I imagine the buildfarm does not need to provide us with
>> any tools for doing analysis on this. Ideally, there would be some
>> run_id that we could link it back to the test run which would give us
>> the commit SHA, and the animal that it ran on. Joining to details
>> about the animal could be useful too, e.g perhaps a certain test
>> always fails on 32-bit machines.
>>
>> I suppose that maybe we could modify pg_regress to add a command line
>> option to have it write out a machine-readable file, e.g:
>> testname,result,runtime\n, then just have the buildfarm client ship
>> that off to the buildfarm server to record in the database.
> That seems like it'd be the best approach to me, though I'd defer to
> Andrew on it.
>
> By the way, if you'd like access to the buildfarm archive server where
> all this stuff is stored, that can certainly be arranged, just let me
> know.
>

Yeah, we'll need to work out where to stash the file. The client will
pick up anything in src/regress/log for "make check", but would need
adjusting for other steps that invoke pg_regress. I'm getting close to
cutting a new client release, but I can delay it till we settle this.

On the server side, we could add a table with a key of <animal,
snapshot, branch, step, testname> but we'd need to make sure those test
names were unique. Maybe we need a way of telling pg_regress to prepend
a module name (e.g. btree_gist ot plperl) to the test name.

cheers

andrew

--
Andrew Dunstan https://www.2ndQuadrant.com
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