Re: pgbench more operators & functions
От | Fabien COELHO |
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Тема | Re: pgbench more operators & functions |
Дата | |
Msg-id | alpine.DEB.2.20.1610081414370.15877@lancre обсуждение исходный текст |
Ответ на | Re: pgbench more operators & functions (Amit Kapila <amit.kapila16@gmail.com>) |
Ответы |
Re: pgbench more operators & functions
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Список | pgsql-hackers |
Hello Amit. >> Also, given the heavy UPDATE nature of the pgbench test, a non 100% default >> fill factor on some tables would make sense. > > FWIW, sometime back I have seen that with fill factor 80, at somewhat > moderate client counts (32) on 192 - Hyper Threaded m/c, the > performance is 20~30% better, but at higher client counts, it was same > as 100 fill factor. The 20-30% figure is consistent with figures I collected 2 years ago about fill factor on HDD, see the beginning run of: http://blog.coelho.net/database/2014/08/23/postgresql-fillfactor-and-update.html Although I found that the advantages is reduced after some time because once a page has got an update it has some free space which can be taken advantage of later on, if the space was not reclaimed by vacuum. I cannot understand why there would be no advantage with more clients, though... Alas, performance testing is quite sensitive to many details:-( -- Fabien.
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