Re: [HACKERS] [COMMITTERS] pgsql: Fix freezing of a dead HOT-updatedtuple

Peter Geoghegan wrote:
> On Fri, Oct 6, 2017 at 2:09 PM, Wong, Yi Wen <yiwong@amazon.com> wrote:
> > Yesterday, I've been spending time with pg_visibility on the pages when I reproduce the issue in 9.6.
> > None of the all-frozen or all-visible bits are necessarily set in problematic pages.
> 
> Since this happened yesterday, I assume it was with an unfixed version?
> 
> 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

Note that you need to use pg10's psql because of the \if lines in
lock.sql.  For some runs I change the values to compare random() to, and
originally the commented out section in lock.sql was not commented out,
but I'm fairly sure the failures I saw where with this version.  Also, I
sometime change the 5 in the `seq` command to higher values (180, 250).

I didn't find the filler column to have any effect, so I took that out.

-- 
Álvaro Herrera                https://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services

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