Message-ID: <add210d6-0278-d00e-ebe5-4e5e42e08ecc@gmail.com>
Date: Tue, 7 Nov 2023 14:00:00 +0300
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Subject: Re: collect_corrupt_items_vacuum.patch
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To: Alexander Korotkov <aekorotkov@gmail.com>,
 Daniel Gustafsson <daniel@yesql.se>
Cc: Daniel Shelepanov <deniel1495@mail.ru>,
 Nikita Malakhov <hukutoc@gmail.com>, Michael Paquier <michael@paquier.xyz>,
 Robert Haas <robertmhaas@gmail.com>, Tom Lane <tgl@sss.pgh.pa.us>,
 PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>,
 Andres Freund <andres@anarazel.de>
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From: Alexander Lakhin <exclusion@gmail.com>
In-Reply-To: <CAPpHfdu6c=dQHq4r_xXbcAu0T4P28wv6x7QTwBZa7idv6nZsrA@mail.gmail.com>
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Hi Alexander,

06.11.2023 12:30, Alexander Korotkov wrote:
> Surely these would significantly sacrifice accuracy. But we have to do
> so in order to avoid reporting false errors.
>

I've reduced the dirty reproducer Daniel Shelepanov posted initially
to the following:
numdbs=10
for ((d=1;d<=$numdbs;d++)); do
   createdb db$d
   psql db$d -c "create extension pg_visibility"
done

for ((i=1;i<=300;i++)); do
echo "iteration $i"
for ((d=1;d<=$numdbs;d++)); do
(
echo "
create table vacuum_test as select 42 i;
vacuum (disable_page_skipping) vacuum_test;
select * from pg_check_visible('vacuum_test');
" | psql db$d -a -q >psql-$d.log 2>&1
) &
done
wait

res=0
for ((d=1;d<=$numdbs;d++)); do
grep -q '0 rows' psql-$d.log || { echo "Error condition in psql-$d.log:"; cat psql-$d.log; res=1; break; }
psql db$d -q -c "drop table vacuum_test"
done
[ $res == 0 ] || break;
done

It looks like the v2 patch doesn't fix the original issue. Maybe I miss
something, but with the patch applied, I see the failure immediately,
though without the patch several iterations are needed to get it.

Best regards,
Alexander