Re: lifetime of the old CTID

El día martes, julio 05, 2022 a las 04:17:41p. m. +0200, Laurenz Albe escribió:

> > > Another explanation could be that the HOT chain was pruned while you were away.
> >
> > I've read now about HOT and understand that autovacuum will prune the
> > HOT chain. But also a simple SELECT seems to remove it:
> >
> > sisis=# SELECT currtid2('d01buch'::text, '(29036,11)'::tid);
> >  currtid2 
> > -----------
> >  (29036,7)
> >
> >
> > sisis=# select ctid, d01gsi from d01buch where d01gsi = '0240564';
> >    ctid    |           d01gsi           
> > -----------+-----------------------------
> >  (29036,7) | 0240564                   
> >
> >
> > sisis=# SELECT currtid2('d01buch'::text, '(29036,11)'::tid);
> >   currtid2 
> > ------------
> >  (29036,11)
>
> Right. Heap-Only tuples can also vanish without autovacuum; that is why I
> suspected it might have been that.

Hi Laurenz, ist there any way to keep/freeze such tuples until the run
of the next autovaccum? Some kind of config value in 13.x or 14.x? Or
even a code change for this? We compile on Linux from the sources and
have already some code changes in place...

Thanks

matthias

--
Matthias Apitz, ✉ guru(at)unixarea(dot)de, http://www.unixarea.de/ +49-176-38902045
Public GnuPG key: http://www.unixarea.de/key.pub