Re: SLRU optimization - configurable buffer pool and partitioning the SLRU lock - Mailing list pgsql-hackers

From Andrey M. Borodin
Subject Re: SLRU optimization - configurable buffer pool and partitioning the SLRU lock
Date
Msg-id 01204A45-D792-4EAD-8963-F13B47972B87@yandex-team.ru
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In response to Re: SLRU optimization - configurable buffer pool and partitioning the SLRU lock  (Alvaro Herrera <alvherre@alvh.no-ip.org>)
Responses Re: SLRU optimization - configurable buffer pool and partitioning the SLRU lock
Re: SLRU optimization - configurable buffer pool and partitioning the SLRU lock
List pgsql-hackers

> On 6 Nov 2023, at 14:31, Alvaro Herrera <alvherre@alvh.no-ip.org> wrote:
>
> dynahash is notoriously slow, which is why we have simplehash.h since
> commit b30d3ea824c5.  Maybe we could use that instead.

Dynahash has lock partitioning. Simplehash has not, AFAIK.
The thing is we do not really need a hash function - pageno is already a best hash function itself. And we do not need
tocope with collisions much - we can evict a collided buffer. 

Given this we do not need a hashtable at all. That’s exact reasoning how banks emerged, I started implementing dynahsh
patchin April 2021 and found out that “banks” approach is cleaner. However the term “bank” is not common in software,
it’staken from hardware cache. 


Best regards, Andrey Borodin.


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