In yesterday's discussions about FOR UPDATE there was some mention of
making it not propagate into WITH subqueries:
http://archives.postgresql.org/pgsql-hackers/2009-10/msg01540.php
That is, given
WITH w AS (SELECT * FROM foo) SELECT * FROM w, bar ... FOR UPDATE
should foo be locked FOR UPDATE or not? The current behavior is that
the code attempts to propagate FOR UPDATE into the WITH, and fails
(the parser rejects it in some cases, and the planner in others ---
AFAICT there is no case where it actually works). This is pretty
useless, and it's also at odds with the philosophy we adopted that WITH
queries execute independently of the primary query. So I think there
was consensus to change it to have FOR UPDATE ignore WITH references.
What I'm wondering at the moment is if there's any objection to
back-patching the change into 8.4. Given the lack of any way to have a
working query depend on this behavior, it doesn't seem that there could
be a problem, but can anyone think of an objection I missed?
regards, tom lane
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