Horton

Re: should we have a fast-path planning for OLTP starjoins?

Bruce Momjian <bruce@momjian.us>

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From: Bruce Momjian <bruce@momjian.us>
To: Robert Haas <robertmhaas@gmail.com>
Cc: Tomas Vondra <tomas@vondra.me>, Tom Lane <tgl@sss.pgh.pa.us>, PostgreSQL Hackers <pgsql-hackers@postgresql.org>
Date: 2025-12-21T02:08:47Z
Lists: pgsql-hackers 
On Sat, Dec 20, 2025 at 05:49:24PM -0500, Bruce Momjian wrote:
> What Robert is saying in the above paragraph is even more complex ---
> that we might want to use an index on the fact table for a merge join of
> a stage 2 or 3 join, and then do the other joins.  How would we detect
> this?  Could we run each join on its own and see which ones choose merge
> join, and move them to stage 1?

Thinking some more, how likely would we do a merge join before applying
a restrictive join?

-- 
  Bruce Momjian  <bruce@momjian.us>        https://momjian.us
  EDB                                      https://enterprisedb.com

  Do not let urgent matters crowd out time for investment in the future.