Re: Avoid MVCC using exclusive lock possible?
От | Yves Darmaillac |
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Тема | Re: Avoid MVCC using exclusive lock possible? |
Дата | |
Msg-id | 4062D8E9.8020009@club-internet.fr обсуждение исходный текст |
Ответ на | Re: Avoid MVCC using exclusive lock possible? (Andrew Sullivan <ajs@crankycanuck.ca>) |
Список | pgsql-hackers |
Andrew Sullivan a écrit : >On Sun, Feb 29, 2004 at 10:43:34AM -0500, Tom Lane wrote: > > >>general I think our VACUUM-based approach is superior to the >>Oracle-style UNDO approach, because it pushes the maintenance overhead >>out of foreground transaction processing and into a schedulable >>background process. Certainly any Oracle DBA will tell you that huge >> >> > >I completely agree with this. If the recent work on lowering the >overall cost ov VACUUM on loaded systems pays off, then I think there >can be no argument that the work-now, vacuum-later strategy is the >best approach, simply because it deals with the outlying and >unexpected cases better than the alternatives. I know too many >people who have been burned by running out of rollback segments when >some use pattern emerged that they hadn't planned for. > >A > I agree too. The VACUUM aproach is better as it reduces fragmentation and chained rows due to columns size change.
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