public inbox for [email protected]
help / color / mirror / Atom feedFrom: Andres Freund <[email protected]>
To: Melanie Plageman <[email protected]>
Cc: Matthias van de Meent <[email protected]>
Cc: [email protected]
Cc: Thomas Munro <[email protected]>
Cc: Heikki Linnakangas <[email protected]>
Cc: Noah Misch <[email protected]>
Cc: Robert Haas <[email protected]>
Cc: Michael Paquier <[email protected]>
Subject: Re: Buffer locking is special (hints, checksums, AIO writes)
Date: Tue, 2 Dec 2025 19:47:35 -0500
Message-ID: <lneuyxqxamqoayd2ntau3lqjblzdckw6tjgeu4574ezwh4tzlg@noioxkquezdw> (raw)
In-Reply-To: <3nce7i72ayzkunai6mkz24ckbxk74jodz4ua2chcdrwppxlxcd@w6x5kfkjrkru>
References: <yivb2evcrj7fna5ymuunw3g5u5xxttwjbjxaa4ofkfkviystjv@4dfylftqxyxh>
<6kmid26do57ykqfpvq6iieniy4djsymhrypkjccazq5g4bbe6a@2y6owwv7qpex>
<CAEze2WgGe8vjj3jiWqUugWuwLJ9cLryaGrnASjm-yJ=tEALX2A@mail.gmail.com>
<pmto7djq64mei53p7r5smfync2waittilhbuzc7j7lpflf2b3y@laz7r76y5pux>
<CAEze2WjeK9CY003S4dmCugv_H4tz9AaXgnqW+wTc=BaPDg+2xg@mail.gmail.com>
<3je3ahgf7rrmmurxo6hnlhg5d3ffwfrtjwjxd6jm5srlv5iebp@vxqk5qtgmowr>
<3w7v3w6a57jnssokap4k7thoekig72flnyhd4wp3yftzdd7lm7@f6lpcfen6hr7>
<6rgb2nvhyvnszz4ul3wfzlf5rheb2kkwrglthnna7qhe24onwr@vw27225tkyar>
<CAAKRu_ZcZCXNUWfhEg4qOYuRO8T1x3_gvaUFFrwgCfY0RnVhkg@mail.gmail.com>
<3nce7i72ayzkunai6mkz24ckbxk74jodz4ua2chcdrwppxlxcd@w6x5kfkjrkru>
Hi,
On 2025-11-25 11:54:00 -0500, Andres Freund wrote:
> Thanks a lot for that detailed review! A few questions and comments, before I
> try to address the comments in the next version.
Here's that new new version, with the following changes
- Some more micro-optimizations, most importantly adding a commit that doesn't
initialize the delay in LockBufHdr() unless needed. With those I don't see a
consistent slowdown anymore (slight speedup on one workstation, slight
slowdown on another, in an absurdly adverse workload)
- Tried to address Melanie's feedback, with some exceptions (some noted below,
but I also need to make another pass through the reviews)
- re-implemented AssertNotCatalogBufferLock() in the new world
- Substantially expanded comments around setting hint bits (in buffer/README,
heapam_visibility.c and bufmgr.c)
- split out the change to fsm_vacuum_page() to start to lock the page into is
own commit
- reordered patch series so that smaller changes are before the 64bit-state
and "Implement buffer content locks independently of" commits, so they can
be committed while we finish cleaning the later changes
- I didn't invest much in cleaning up the later patches ("Don't copy pages
while writing out" and "Make UnlockReleaseBuffer() more efficient") yet,
wanted to focus on the earlier patches first
Todo:
- still need to rename ResOwnerReleaseBufferPin(). Wondering about what to
rename ResourceOwnerDesc.name to. "buffer ownership" maybe? Not great...
- gistkillitems() complaint by Melanie
- amortize vs batch vs SetHintBits comment + SHB_* names
- for the next version I'll remove the BATCHMVCC_FEWER_ARGS conditionals from
0010. I don't love needing BatchMVCCState but I don't really see an
alternative, the performance difference is pretty persistent.
Questions:
- ForEachLWLockHeldByMe() and LWLockDisown() aren't used anymore, should we
remove them?
Greetings,
Andres Freund
view thread (57+ messages) latest in thread
reply
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Reply to all the recipients using the --to and --cc options:
reply via email
To: [email protected]
Cc: [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected]
Subject: Re: Buffer locking is special (hints, checksums, AIO writes)
In-Reply-To: <lneuyxqxamqoayd2ntau3lqjblzdckw6tjgeu4574ezwh4tzlg@noioxkquezdw>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by agora; see mirroring instructions
for how to clone and mirror all data and code used for this inbox