Re: Fast insert, but slow join and updates for table with 4 billion rows
| От | Tom Lane |
|---|---|
| Тема | Re: Fast insert, but slow join and updates for table with 4 billion rows |
| Дата | |
| Msg-id | 21210.1477313528@sss.pgh.pa.us обсуждение исходный текст |
| Ответ на | Fast insert, but slow join and updates for table with 4 billion rows (Lars Aksel Opsahl <Lars.Opsahl@nibio.no>) |
| Ответы |
Re: Fast insert, but slow join and updates for table with 4
billion rows
Re: Fast insert, but slow join and updates for table with 4 billion rows |
| Список | pgsql-performance |
Lars Aksel Opsahl <Lars.Opsahl@nibio.no> writes:
> In this example I have two tables one with 4 billion rows and another with 50000 rows and then I try to do a standard
simplejoin between this two tables and this takes 397391 ms. with this SQL (the query plan is added is further down)
This particular query would work a lot better if you had an index on
nora_bc25_observation (point_uid_ref, epoch), ie both join columns
in one index. I get the impression that that ought to be the primary
key of the table, which would be an even stronger reason to have a
unique index on it.
regards, tom lane
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