Horton

Re: Bug in query rewriter - hasModifyingCTE not getting set

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

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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Greg Nancarrow <gregn4422@gmail.com>
Cc: PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2021-02-06T23:03:21Z
Lists: pgsql-hackers 
Greg Nancarrow <gregn4422@gmail.com> writes:
> I found a bug in the query rewriter. If a query that has a modifying
> CTE is re-written, the hasModifyingCTE flag is not getting set in the
> re-written query.

Ugh.

> I've attached the patch with the suggested fix (reviewed by Amit Langote).

I think either the bit about rule_action is unnecessary, or most of
the code immediately above this is wrong, because it's only updating
flags in sub_action.  Why do you think it's necessary to change
rule_action in addition to sub_action?

			regards, tom lane

Commits

  1. Fix rewriter to set hasModifyingCTE correctly on rewritten queries.

  2. Enable parallel SELECT for "INSERT INTO ... SELECT ...".

  3. Revert "Propagate CTE property flags when copying a CTE list into a rule."

  4. Propagate CTE property flags when copying a CTE list into a rule.