Re: [HACKERS] [PATCH] Push limit to sort through a subquery
| От | Douglas Doole |
|---|---|
| Тема | Re: [HACKERS] [PATCH] Push limit to sort through a subquery |
| Дата | |
| Msg-id | CADE5jYLQEwxDFHVYRqDnkZQJqCBSs+Hj9s4nMjijO=3L_AJXdg@mail.gmail.com обсуждение исходный текст |
| Ответ на | Re: [HACKERS] [PATCH] Push limit to sort through a subquery (Robert Haas <robertmhaas@gmail.com>) |
| Ответы |
Re: [HACKERS] [PATCH] Push limit to sort through a subquery
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| Список | pgsql-hackers |
Buildfarm members with force_parallel_mode=regress are failing now. I
haven't had a chance to investigate exactly what's going on here, but
I think there are probably several issues:
Not an auspicious beginning for my first patch :-(
3. However, even if it did that, it would only affect the leader, not
the workers, because each worker will of course have a separate copy
of each executor state node. We could fix that by having the Gather
or Gather Merge node also store the bound and propagate that to each
worker via DSM, and then have each worker call pass_down_bound itself.
(This would require a bit of refactoring of the API for
pass_down_bound, but it looks doable.)
From previous experience, pushing the limit to the workers has the potential to be a big win .
In the short run, I'm not sure we have a better alternative than
removing this test - unless somebody has a better idea? - but it would
be good to work on all of the above problems.
I haven't played with parallel mode at all yet. Is it possible to disable force_parallel_mode for the new test? If not, then I'd agree that removing the test is probably the only reasonable short term fix.
- Doug
Salesforce
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