Merlin Moncure <mmonc...@gmail.com> writes:
> Can't it be forced like this (assuming it is in fact a vanilla order
> by problem)?
> EXPLAIN DELETE FROM test USING (SELECT g FROM test ORDER BY
> ctid FOR UPDATE) x where x.g = test.g;
> (emphasis on 'for update')
Hm ... yeah, that might work, once you redefine the problem as "get the
row locks in a consistent order" rather than "do the updates in a
consistent order". But I'd be inclined to phrase it as
EXPLAIN DELETE FROM test USING (SELECT ctid FROM test ORDER BY
g FOR UPDATE) x where x.ctid = test.ctid;
I'm not sure that "ORDER BY ctid" is really very meaningful here; think
about FOR UPDATE switching its attention to updated versions of rows.
regards, tom lane
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