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@momjian.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@momjian.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@momjian.us>        http://momjian.us EnterpriseDB
http://enterprisedb.com
 + If your life is a hard drive, Christ can be your backup. +