Re: Document efficient self-joins / UPDATE LIMIT techniques.

>
> > As for whether it's commonplace, when I was a consultant I had a number
> > of customers that I had who bemoaned how large updates caused big
> > replica lag, basically punishing access to records they did care about
> > in order to properly archive or backfill records they don't care about.
> > I used the technique a lot, putting the update/delete in a loop, and
> > often running multiple copies of the same script at times when I/O
> > contention was low, but if load levels rose it was trivial to just kill
> > a few of the scripts until things calmed down.
>
> I've also used the technique quite a lot, but only using the PK,
> didn't know about the ctid trick, so many thanks for documenting it.


tid-scans only became a thing a few versions ago (12?). Prior to that, PK
was the only way to go.