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

Wood, Dan wrote:
> Whatever you do make sure to also test 250 clients running lock.sql.  Even with the communities fix plus YiWen’s fix
Ican still get duplicate rows.  What works for “in-block” hot chains may not work when spanning blocks.
 

Good idea.  You can achieve a similar effect by adding a filler column,
and reducing fillfactor.

> Once nearly all 250 clients have done their updates and everybody is
> waiting to vacuum which one by one will take a while I usually just
> “pkill -9 psql”.  After that I have many of duplicate “id=3” rows.

Odd ...

> On top of that I think we might have a lock leak.  After the pkill I
> tried to rerun setup.sql to drop/create the table and it hangs.  I see
> an autovacuum process starting and existing every couple of seconds.
> Only by killing and restarting PG can I drop the table.

Please do try to figure this one out.  It'd be a separate problem,
worthy of its own thread.

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


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