Robert Haas <robertmh...@gmail.com> writes: > On Tue, Oct 27, 2009 at 11:22 AM, Tom Lane <t...@sss.pgh.pa.us> wrote: >> What I am thinking we should do is define that FOR UPDATE happens before >> ORDER BY or LIMIT normally, but that if the FOR UPDATE is inherited from >> an outer query level, it happens after the sub-select's ORDER BY or >> LIMIT. The first provision fixes the bugs noted in our documentation, >> and the second one allows people to get back the old behavior if they >> need it for performance. This also seems reasonably non-astonishing >> from a semantic viewpoint.
> When you refer to an "outer query level", is that the same thing as a > sub-select? If so, I think I agree that the behavior is > non-astonishing. Right, the case would be something like select * from (select * from foo order by x limit n) ss for update of ss; If you try this in any existing release it will just fail, because the planner knows that it hasn't got a way to execute FOR UPDATE in a subquery. regards, tom lane -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers