Horton

Re: SLRU optimization - configurable buffer pool and partitioning the SLRU lock

x4mmm@yandex-team.ru

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From: "Andrey M. Borodin" <x4mmm@yandex-team.ru>
To: Dilip Kumar <dilipbalaut@gmail.com>
Cc: Alvaro Herrera <alvherre@alvh.no-ip.org>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2023-11-19T07:09:18Z
Lists: pgsql-hackers 

> On 17 Nov 2023, at 16:11, Dilip Kumar <dilipbalaut@gmail.com> wrote:
> 
> On Fri, Nov 17, 2023 at 1:09 PM Dilip Kumar <dilipbalaut@gmail.com> wrote:
>> 
>> On Thu, Nov 16, 2023 at 3:11 PM Alvaro Herrera <alvherre@alvh.no-ip.org> wrote:
> 
> PFA, updated patch version, this fixes the comment given by Alvaro and
> also improves some of the comments.

I’ve skimmed through the patch set. Here are some minor notes.

1. Cycles “for (slotno = bankstart; slotno < bankend; slotno++)” in SlruSelectLRUPage() and SimpleLruReadPage_ReadOnly() now have identical comments. I think a little of copy-paste is OK.
But SimpleLruReadPage_ReadOnly() does pgstat_count_slru_page_hit(), while SlruSelectLRUPage() does not. This is not related to the patch set, just a code nearby.

2. Do we really want these functions doing all the same?
extern bool check_multixact_offsets_buffers(int *newval, void **extra,GucSource source);
extern bool check_multixact_members_buffers(int *newval, void **extra,GucSource source);
extern bool check_subtrans_buffers(int *newval, void **extra,GucSource source);
extern bool check_notify_buffers(int *newval, void **extra, GucSource source);
extern bool check_serial_buffers(int *newval, void **extra, GucSource source);
extern bool check_xact_buffers(int *newval, void **extra, GucSource source);
extern bool check_commit_ts_buffers(int *newval, void **extra,GucSource source);

3. The name SimpleLruGetSLRUBankLock() contains meaning of SLRU twice. I’d suggest truncating prefix of infix.

I do not have hard opinion on any of this items.


Best regards, Andrey Borodin.

Commits

  1. Fix zeroing of pg_serial page without SLRU bank lock

  2. Fix misspelled assertions

  3. GUC table: Add description to computed variables

  4. Improve performance of subsystems on top of SLRU

  5. Rename SLRU elements in view pg_stat_slru

  6. Use atomic access for SlruShared->latest_page_number

  7. Split use of SerialSLRULock, creating SerialControlLock

  8. Index SLRUs by 64-bit integers rather than by 32-bit integers

  9. Add a macro templatized hashtable.