Horton

Re: [HACKERS] kqueue

Tom Lane <tgl@sss.pgh.pa.us>

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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Matteo Beccati <php@beccati.com>
Cc: Thomas Munro <thomas.munro@gmail.com>, Peter Eisentraut <peter.eisentraut@2ndquadrant.com>, Rui DeSousa <rui@crazybean.net>, Torsten Zuehlsdorff <mailinglists@toco-domains.de>, Keith Fiske <keith@omniti.com>, Andres Freund <andres@anarazel.de>, Heikki Linnakangas <hlinnaka@iki.fi>, Marko Tiikkaja <marko@joh.to>, Alvaro Herrera <alvherre@2ndquadrant.com>, Robert Haas <robertmhaas@gmail.com>, Pg Hackers <pgsql-hackers@postgresql.org>, Noah Misch <noah@leadboat.com>
Date: 2020-01-22T16:06:59Z
Lists: pgsql-hackers 
Matteo Beccati <php@beccati.com> writes:
> On 21/01/2020 02:06, Thomas Munro wrote:
>> [1] https://www.postgresql.org/message-id/CA%2BhUKGJAC4Oqao%3DqforhNey20J8CiG2R%3DoBPqvfR0vOJrFysGw%40mail.gmail.com

> I had a NetBSD 8.0 VM lying around and I gave the patch a spin on latest
> master.
> With the kqueue patch, a pgbench -c basically hangs the whole postgres
> instance. Not sure if it's a kernel issue, HyperVM issue o what, but
> when it hangs, I can't even kill -9 the postgres processes or get the VM
> to properly shutdown. The same doesn't happen, of course, with vanilla
> postgres.

I'm a bit confused about what you are testing --- the kqueue patch
as per this thread, or that plus the WaitLatch refactorizations in
the other thread you point to above?

I've gotten through check-world successfully with the v14 kqueue patch
atop yesterday's HEAD on:

* macOS Catalina 10.15.2 (current release)
* FreeBSD/amd64 12.0-RELEASE-p12
* NetBSD/amd64 8.1
* NetBSD/arm 8.99.41
* OpenBSD/amd64 6.5

(These OSes are all on bare metal, no VMs involved)

This just says it doesn't lock up, of course.  I've not attempted
any performance-oriented tests.

			regards, tom lane

Commits

  1. Add kqueue(2) support to the WaitEventSet API.

  2. Add WL_EXIT_ON_PM_DEATH pseudo-event.

  3. Be conservative about alignment requirements of struct epoll_event.

  4. Make idle backends exit if the postmaster dies.