Horton

Re: making update/delete of inheritance trees scale better

Robert Haas <robertmhaas@gmail.com>

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From: Robert Haas <robertmhaas@gmail.com>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Amit Langote <amitlangote09@gmail.com>, Heikki Linnakangas <hlinnaka@iki.fi>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2021-03-31T17:37:27Z
Lists: pgsql-hackers 
On Wed, Mar 31, 2021 at 1:24 PM Tom Lane <tgl@sss.pgh.pa.us> wrote:
> I agree that we have some existing behavior that's related to this, but
> it's still messy, and I couldn't find any evidence that suggested that the
> runtime lookup costs anything.  Typical subplans are going to deliver
> long runs of tuples from the same target relation, so as long as we
> maintain a one-element cache of the last lookup result, it's only about
> one comparison per tuple most of the time.

OK, that's pretty fair.

-- 
Robert Haas
EDB: http://www.enterprisedb.com

Commits

  1. Rework planning and execution of UPDATE and DELETE.

  2. Faster expression evaluation and targetlist projection.