Thanks, Tom.
After you made your recommendation, the result returned much quicker at 2.62 seconds, but v15 is still faster at 1.82 seconds. No modification was made to the function.
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Monday, April 28, 2025 at 9:59 AM
To: marcos sicat <marcos.sicat@atlasifs.com>
Cc: Pavel Stehule <pavel.stehule@gmail.com>, pgsql-bugs@lists.postgresql.org <pgsql-bugs@lists.postgresql.org>
Subject: Re: Postgres 17.4 is much slower than Postgres 15.12 using RECURSIVE
marcos sicat <marcos.sicat@atlasifs.com> writes:
> The function is the same between v15 and v17. Is there a subtle difference in performance for nested subqueries in v17?
Your next step should be to compare the plans for the function's
query. The auto_explain or pg_stat_statements extensions could
be used to check that in-situ, if manually EXPLAINing that query
doesn't yield insight.
regards, tom lane
