Re: parse partition strategy string in gram.y
От | Alvaro Herrera |
---|---|
Тема | Re: parse partition strategy string in gram.y |
Дата | |
Msg-id | 20221025232336.6zisdii6n6sbdacq@alvherre.pgsql обсуждение исходный текст |
Ответ на | Re: parse partition strategy string in gram.y (Alvaro Herrera <alvherre@alvh.no-ip.org>) |
Список | pgsql-hackers |
On 2022-Oct-26, Alvaro Herrera wrote: > On 2022-Oct-25, Finnerty, Jim wrote: > > > Or if you know the frequencies of the highly frequent values of the > > partitioning key at the time the partition bounds are defined, you > > could define hash ranges that contain approximately the same number of > > rows in each partition. A parallel sequential scan of all partitions > > would then perform better because data skew is minimized. > > This sounds very much like list partitioning to me. ... or maybe you mean "if the value is X then use this specific partition, otherwise use hash partitioning". It's a bit like multi-level partitioning, but not really. (You could test this idea by using two levels, list partitioning on top with a default partition which is in turn partitioned by hash; but this is unlikely to work well for large scale in practice. Or does it?) -- Álvaro Herrera 48°01'N 7°57'E — https://www.EnterpriseDB.com/ "Entristecido, Wutra (canción de Las Barreras) echa a Freyr a rodar y a nosotros al mar"
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