Horton

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

Tom Lane <tgl@sss.pgh.pa.us>

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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Corey Huinker <corey.huinker@gmail.com>
Cc: Joel Jacobson <joel@compiler.org>, Laurenz Albe <laurenz.albe@cybertec.at>, vignesh C <vignesh21@gmail.com>, pgsql-hackers@lists.postgresql.org, Marko Tiikkaja <marko@joh.to>
Date: 2024-04-07T20:29:03Z
Lists: pgsql-hackers 
Corey Huinker <corey.huinker@gmail.com> writes:
>> 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.

I think we had TID scans for awhile before it was possible to use
them in joins, although I don't recall the details of that.
Anyway, pushed after some additional wordsmithing.

			regards, tom lane

Commits

  1. Doc: show how to get the equivalent of LIMIT for UPDATE/DELETE.