Re: Parallel Inserts in CREATE TABLE AS
| От | Dilip Kumar |
|---|---|
| Тема | Re: Parallel Inserts in CREATE TABLE AS |
| Дата | |
| Msg-id | CAFiTN-vRLMZTOPvEvXo=s0Omti4hGG6Vozvuw2dKLvB3gDojZw@mail.gmail.com обсуждение исходный текст |
| Ответ на | RE: Parallel Inserts in CREATE TABLE AS ("tsunakawa.takay@fujitsu.com" <tsunakawa.takay@fujitsu.com>) |
| Ответы |
RE: Parallel Inserts in CREATE TABLE AS
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| Список | pgsql-hackers |
From: Dilip Kumar <dilipbalaut@gmail.com>
> I think some other cause of contention on relation extension locks are
> 1. CTAS is using a buffer strategy and due to that, it might need to
> evict out the buffer frequently for getting the new block in. Maybe
> we can identify by turning off the buffer strategy for CTAS and
> increasing the shared buffer so that data fits in memory.
Yes, both Bhrath-san (on a rich-man's machine) and I (on a poor-man's VM) saw that it's effective. I think we should remove this shackle from CTAS.
The question is why CTAS chose to use BULKWRITE strategy in the past. We need to know that to make a better decision.
Basically you are creating a new table and loading data to it and that means you will be less likely to access those data soon so for such thing spoiling buffer cache may not be a good idea. I was just suggesting only for experiments for identifying the root cause.
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