Horton

Re: improve EXPLAIN for wide tables

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

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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Sami Imseih <samimseih@gmail.com>
Cc: pgsql-hackers@postgresql.org
Date: 2024-12-16T16:21:23Z
Lists: pgsql-hackers 
Sami Imseih <samimseih@gmail.com> writes:
> Looking further into this improvement, I started to question if it is
> necessary to make columns unique for EXPLAIN purposes?

Yes, otherwise references to them elsewhere in the plan will be
ambiguous.

It looks like your proposal tries to dodge that by unique-ifying
in some cases but not others, which strikes me as a totally
random and confusing thing to do.

Is there any reason to think that 52c707483 wasn't a sufficient
response to this issue?

			regards, tom lane

Commits

  1. Skip useless calculation of join RTE column names during EXPLAIN.

  2. Use a hash table to de-duplicate column names in ruleutils.c.