Re: making update/delete of inheritance trees scale better

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

From: Tom Lane <tgl@sss.pgh.pa.us>
To: Robert Haas <robertmhaas@gmail.com>
Cc: Amit Langote <amitlangote09@gmail.com>, Heikki Linnakangas <hlinnaka@iki.fi>, Ashutosh Bapat <ashutosh.bapat.oss@gmail.com>, PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2021-02-05T21:53:44Z
Lists: pgsql-hackers
Robert Haas <robertmhaas@gmail.com> writes:
> As to why it causes us pain, I don't have a full picture of that.
> Target list construction is one problem: we build all these target
> lists for intermediate notes during planning and they're long enough
> -- if the user has a bunch of columns -- and planning is cheap enough
> for some queries that the sheer time to construct the list shows up
> noticeably in profiles.

Well, the tlist data structure is just about completely separate from
the TupleTableSlot mechanisms.  I'm more prepared to believe that
we could improve on the former, though I don't have any immediate
ideas about how.

			regards, tom lane



Commits

  1. Rework planning and execution of UPDATE and DELETE.

  2. Faster expression evaluation and targetlist projection.