Re: parallel "return query" is no good
Robert Haas <robertmhaas@gmail.com>
From: Robert Haas <robertmhaas@gmail.com>
To: Alvaro Herrera <alvherre@2ndquadrant.com>
Cc: "pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>
Date: 2017-03-24T16:43:59Z
Lists: pgsql-hackers
On Thu, Mar 23, 2017 at 1:53 PM, Alvaro Herrera <alvherre@2ndquadrant.com> wrote: > Robert Haas wrote: >> I guess the downside of back-patching this is that it could cause a >> plan change for somebody which ends up being worse. On the whole, >> serial execution of queries intended to be run in parallel isn't >> likely to work out well, but it's always possible somebody has a cases >> where it happens to be winning, and this could break it. So maybe I >> should do this only in master? Thoughts? > > I think that the chances of someone depending on a parallel plan running > serially by accident which is better than the non-parallel plan, are > pretty slim. > > +1 for back-patching. All right, done. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company
Commits
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plpgsql: Don't generate parallel plans for RETURN QUERY.
- 5674a258fd7e 9.6.3 landed
- f120b614e070 10.0 landed
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Determine whether it's safe to attempt a parallel plan for a query.
- 7aea8e4f2daa 9.6.0 cited