Re: [COMMITTERS] pgsql: Fix freezing of a dead HOT-updated tuple

On Sat, Oct 7, 2017 at 1:31 AM, Alvaro Herrera <alvherre(at)alvh(dot)no-ip(dot)org> wrote:
>> As you must have seen, Alvaro said he has a variant of Dan's original
>> script that demonstrates that a problem remains, at least on 9.6+,
>> even with today's fix. I think it's the stress-test that plays with
>> fillfactor, many clients, etc [1].
>
> I just execute setup.sql once and then run this shell command,
>
> while :; do
> psql -e -P pager=off -f ./repro.sql
> for i in `seq 1 5`; do
> psql -P pager=off -e --no-psqlrc -f ./lock.sql &
> done
> wait && psql -P pager=off -e --no-psqlrc -f ./reindex.sql
> psql -P pager=off -e --no-psqlrc -f ./report.sql
> echo "done"
> done

I cannot reproduce the problem on my personal machine using this
script/stress-test. I tried to do so on the master branch git tip.
This reinforces the theory that there is some timing sensitivity,
because the remaining race condition is very narrow.

--
Peter Geoghegan