Horton

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

Dilip Kumar <dilipbalaut@gmail.com>

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From: Dilip Kumar <dilipbalaut@gmail.com>
To: Alvaro Herrera <alvherre@alvh.no-ip.org>
Cc: tender wang <tndrwang@gmail.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2024-02-01T11:04:06Z
Lists: pgsql-hackers 
On Thu, Feb 1, 2024 at 4:12 PM Dilip Kumar <dilipbalaut@gmail.com> wrote:
>
> On Thu, Feb 1, 2024 at 3:44 PM Alvaro Herrera <alvherre@alvh.no-ip.org> wrote:

> Okay.
> >
> > While I have your attention -- if you could give a look to the 0001
> > patch I posted, I would appreciate it.
> >
>
> I will look into it.  Thanks.

Some quick observations,

Do we need below two write barriers at the end of the function?
because the next instruction is separated by the function boundary

@@ -766,14 +766,11 @@ StartupCLOG(void)
  ..
- XactCtl->shared->latest_page_number = pageno;
-
- LWLockRelease(XactSLRULock);
+ pg_atomic_init_u64(&XactCtl->shared->latest_page_number, pageno);
+ pg_write_barrier();
 }

/*
  * Initialize member's idea of the latest page number.
  */
  pageno = MXOffsetToMemberPage(offset);
- MultiXactMemberCtl->shared->latest_page_number = pageno;
+ pg_atomic_init_u64(&MultiXactMemberCtl->shared->latest_page_number,
+    pageno);
+
+ pg_write_barrier();
 }

I am looking more into this from the concurrency point of view and
will update you soon.

-- 
Regards,
Dilip Kumar
EnterpriseDB: http://www.enterprisedb.com

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.