Feedback-ID: ia2694551:Fastmail
Date: Thu, 23 May 2024 13:22:51 +0200
From: Alvaro Herrera <alvherre@alvh.no-ip.org>
To: Bruce Momjian <bruce@momjian.us>
Cc: PostgreSQL-development <pgsql-hackers@postgresql.org>
Subject: Re: First draft of PG 17 release notes
Message-ID: <202405231122.zew2gncy63fo@alvherre.pgsql>
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Hello,

Regarding this item

: Allow the SLRU cache sizes to be configured (Andrey Borodin, Dilip Kumar)
: 
: The new server variables are commit_timestamp_buffers,
: multixact_member_buffers, multixact_offset_buffers, notify_buffers,
: serializable_buffers, subtransaction_buffers, and transaction_buffers.

I hereby request to be listed as third author of this feature.

Also, I'd like to suggest to make it more verbose, as details might be
useful to users.  Mention that scalability is improved, because
previously we've suggested to recompile with larger #defines, but to be
cautious because values too high degrade performance.  Also mention the
point that some of these grow with shared_buffers is user-visible enough
that it warrants an explicit mention.  How about like this:

: Allow the SLRU cache sizes to be configured and improve performance of
: larger caches
: (Andrey Borodin, Dilip Kumar, Álvaro Herrera)
: 
: The new server variables are commit_timestamp_buffers,
: multixact_member_buffers, multixact_offset_buffers, notify_buffers,
: serializable_buffers, subtransaction_buffers, and transaction_buffers.
: commit_timestamp_buffers, transaction_buffers and
: subtransaction_buffers scale up automatically with shared_buffers.


These three items

: Allow pg_stat_reset_shared() to reset all shared statistics (Atsushi Torikoshi)
: 
: This is done by passing NULL.
: 
: Allow pg_stat_reset_shared('slru') to clear SLRU statistics (Atsushi Torikoshi)
: 
: Now pg_stat_reset_shared(NULL) also resets SLRU statistics.
: 
: Allow pg_stat_reset_slru() to reset all SLRU statistics (Bharath Rupireddy)
: 
: The command pg_stat_reset_slru(NULL) already did this.

seem a bit repetitive.  (I think the first one is also wrong, because it
says you have to pass NULL, but in reality you can also not give an
argument and it works.)  Can we make them a single item?  Maybe
something like

: Improve reset routines for shared statistics (Atsushi Torikoshi, Bharath Rupireddy)
:
: Resetting all shared statistics can now be done with
: pg_stat_reset_shared() or pg_stat_reset_shared(NULL), while SLRU
: statistics can now be reset with pg_stat_reset_shared('slru'),
: pg_stat_reset_slru() and pg_stat_reset_slru(NULL).

-- 
Álvaro Herrera         PostgreSQL Developer  —  https://www.EnterpriseDB.com/
"Find a bug in a program, and fix it, and the program will work today.
Show the program how to find and fix a bug, and the program
will work forever" (Oliver Silfridge)