Re: SLRU optimization - configurable buffer pool and partitioning the SLRU lock
От | Dilip Kumar |
---|---|
Тема | Re: SLRU optimization - configurable buffer pool and partitioning the SLRU lock |
Дата | |
Msg-id | CAFiTN-uw7FrgYVwXscTUKRi7-5YF_nQUM6qBbnjErC8KequO_A@mail.gmail.com обсуждение исходный текст |
Ответ на | Re: SLRU optimization - configurable buffer pool and partitioning the SLRU lock (Alvaro Herrera <alvherre@alvh.no-ip.org>) |
Список | pgsql-hackers |
On Tue, Feb 27, 2024 at 11:41 PM Alvaro Herrera <alvherre@alvh.no-ip.org> wrote:
On 2024-Feb-27, Alvaro Herrera wrote:
> Here's the complete set, with these two names using the singular.
BTW one thing I had not noticed is that before this patch we have
minimum shmem size that's lower than the lowest you can go with the new
code.
This means Postgres may no longer start when extremely tight memory
restrictions (and of course use more memory even when idle or with small
databases). I wonder to what extent should we make an effort to relax
that. For small, largely inactive servers, this is just memory we use
for no good reason. However, anything we do here will impact
performance on the high end, because as Andrey says this will add
calculations and jumps where there are none today.
I was just comparing the minimum memory required for SLRU when the system is minimally configured, correct me if I am wrong.
SLRU unpatched patched
commit_timestamp_buffers 4 16
subtransaction_buffers 32 16
transaction_buffers 4 16
subtransaction_buffers 32 16
transaction_buffers 4 16
multixact_offset_buffers 8 16
multixact_member_buffers 16 16
notify_buffers 8 16
serializable_buffers 16 16
multixact_member_buffers 16 16
notify_buffers 8 16
serializable_buffers 16 16
-------------------------------------------------------------------------------------
total buffers 88 112
total buffers 88 112
so that is < 200kB of extra memory on a minimally configured system, IMHO this should not matter.
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