Re: Latches vs lwlock contention

Maxim Orlov <orlovmg@gmail.com>

From: Maxim Orlov <orlovmg@gmail.com>

To: Heikki Linnakangas <hlinnaka@iki.fi>

Cc: Thomas Munro <thomas.munro@gmail.com>, pgsql-hackers <pgsql-hackers@postgresql.org>, Yura Sokolov <y.sokolov@postgrespro.ru>, Andres Freund <andres@anarazel.de>

Date: 2024-09-10T16:53:02Z

Lists: pgsql-hackers

Attachments

v5-0004-Move-TRACE-calls-into-WaitOnLock.patch (application/octet-stream) patch v5-0004
v5-0001-Remove-LOCK_PRINT-call-that-could-point-to-garbag.patch (application/octet-stream) patch v5-0001
v5-0003-Set-MyProc-heldLocks-in-ProcSleep.patch (application/octet-stream) patch v5-0003
v5-0005-Remove-redundant-lockAwaited-global-variable.patch (application/octet-stream) patch v5-0005
v5-0002-Fix-comment-in-LockReleaseAll-on-when-locallock-n.patch (application/octet-stream) patch v5-0002
v5-0007-Release-partition-lock-a-little-earlier.patch (application/octet-stream) patch v5-0007
v5-0006-Update-local-lock-table-in-ProcSleep-s-caller.patch (application/octet-stream) patch v5-0006
v5-0008-Split-ProcSleep-function-into-JoinWaitQueue-and-P.patch (application/octet-stream) patch v5-0008

I looked at the patch set and found it quite useful.

The first 7 patches are just refactoring and may be committed separately if
needed.
There were minor problems: patch #5 don't want to apply clearly and the #8
is complained
about partitionLock is unused if we build without asserts. So, I add a
PG_USED_FOR_ASSERTS_ONLY
to solve the last issue.

Again, overall patch looks good and seems useful to me. Here is the rebased
v5 version based on Heikki's patch set above.

-- 
Best regards,
Maxim Orlov.

Commits

Fix crash if LockErrorCleanup() is called twice
- 51a0382e8d87 18.0 landed
Split ProcSleep function into JoinWaitQueue and ProcSleep
- 3c0fd64fec8e 18.0 landed
Move TRACE calls into WaitOnLock()
- 6ae0897e4241 18.0 landed
Set MyProc->heldLocks in ProcSleep
- 0464f25b6aa1 18.0 landed
Fix comment in LockReleaseAll() on when locallock->nLock can be zero
- 1fe0466cf2cb 18.0 landed
Allow a no-wait lock acquisition to succeed in more cases.
- 2346df6fc373 17.0 cited
Teach planner about more monotonic window functions
- 456fa635a909 16.0 cited