Re: [PATCHES] Testing pg_terminate_backend()

Magnus, others, how is the SIGTERM testing going?

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Bruce Momjian wrote:
> bruce wrote:
> > Tom Lane wrote:
> > > Bruce Momjian <bruce(at)momjian(dot)us> writes:
> > > > Tom Lane wrote:
> > > >> The closest thing I can think of to an automated test is to run repeated
> > > >> sets of the parallel regression tests, and each time SIGTERM a randomly
> > > >> chosen backend at a randomly chosen time. Then see if anything "funny"
> > >
> > > > Yep, that was my plan, plus running the parallel regression tests you
> > > > get the possibility of >2 backends.
> > >
> > > I was intentionally suggesting only one kill per test cycle. Multiple
> > > kills will probably create an O(N^2) explosion in the set of possible
> > > downstream-failure deltas. I doubt you'd really get any improvement
> > > in testing coverage to justify the much larger amount of hand validation
> > > needed.
> > >
> > > It also strikes me that you could make some simple alterations to the
> > > regression tests to reduce the set of observable downstream deltas.
> > > For example, anyplace where a test loads a table with successive INSERTs
> > > and that table is used by later tests, wrap the INSERT sequence with
> > > BEGIN/END. Then there is only one possible downstream delta (empty
> > > table) and not N different possibilities for an N-row table.
> >
> > I have added pg_terminate_backend() to use SIGTERM and will start
> > running tests as discussed with Tom. I will post my scripts too.
>
> Attached is my test script. I ran it for 14 hours (asserts on),
> running 450 regression tests, with up to seven backends killed per
> regression test.
>
> I have processed the combined regression.diffs files by pickouting out
> all the new error messages. I don't see anything unusual in there.
>
> Should I run it differently?
>
> --
> Bruce Momjian <bruce(at)momjian(dot)us> http://momjian.us
> EnterpriseDB http://enterprisedb.com
>
> + If your life is a hard drive, Christ can be your backup. +

> #!/bin/bash
>
> REGRESSION_DURATION=80 # average duration of regression test in seconds
> OUTFILE=/rtmp/regression.sigterm
>
> # To analyze output, use:
> # grep '^\+ *[A-Z][A-Z]*:' /rtmp/regression.sigterm | sort | uniq | less
>
>
> cd /pg/test/regress
>
> while :
> do
> (
> SLEEP=`expr $RANDOM \* $REGRESSION_DURATION / 32767`
> echo "Sleeping $SLEEP seconds"
> sleep "$SLEEP"
> echo "Trying kill"
> # send up to 7 kill signals
> for X in 1 2 3 4 5 6 7
> do
> psql -p 55432 -qt -c "
> SELECT pg_terminate_backend(stat.procpid)
> FROM (SELECT procpid FROM pg_stat_activity
> ORDER BY random() LIMIT 1) AS stat
> " template1 2> /dev/null
> if [ "$?" -eq 0 ]
> then echo "Kill sent"
> fi
> sleep 5
> done
> ) &
> gmake check
> wait
> [ -s regression.diffs ] && cat regression.diffs >> "$OUTFILE"
> done

>
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--
Bruce Momjian <bruce(at)momjian(dot)us> http://momjian.us
EnterpriseDB http://enterprisedb.com

+ If your life is a hard drive, Christ can be your backup. +