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: 2024-01-08T13:18:09Z
Lists: pgsql-hackers 
On Mon, Jan 8, 2024 at 4:55 PM Alvaro Herrera <alvherre@alvh.no-ip.org> wrote:
>
> The more I look at TransactionGroupUpdateXidStatus, the more I think
> it's broken, and while we do have some tests, I don't have confidence
> that they cover all possible cases.
>
> Or, at least, if this code is good, then it hasn't been sufficiently
> explained.

Any thought about a case in which you think it might be broken, I mean
any vague thought might also help where you think it might not work as
expected so that I can also think in that direction.  It might be
possible that I might not be thinking of some perspective that you are
thinking and comments might be lacking from that point of view.

> If we have multiple processes trying to write bits to clog, and they are
> using different banks, then the LWLockConditionalAcquire will be able to
> acquire the bank lock

Do you think there is a problem with multiple processes getting the
lock? I mean they are modifying different CLOG pages so that can be
done concurrently right?

-- 
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.