On 11/07/18 04:16, Thomas Munro wrote:
On Tue, Jul 10, 2018 at 11:39 PM, Heikki Linnakangas wrote:
I don't have a FreeBSD machine at hand, so I didn't try fixing that
patch.
I updated the FreeBSD version to use the header test approach you
showed, and pushed that too. FWIW the build farm has
On Tue, Jul 10, 2018 at 11:39 PM, Heikki Linnakangas wrote:
> The 'postmaster_possibly_dead' flag is not reset anywhere. So if a process
> receives a spurious death signal, even though postmaster is still alive,
> PostmasterIsAlive() will continue to use the slow path.
+1
> postmaster_possibly_d
On 27/06/18 08:26, Thomas Munro wrote:
On Wed, Apr 25, 2018 at 6:23 PM, Thomas Munro
wrote:
On Tue, Apr 24, 2018 at 7:37 PM, Michael Paquier wrote:
Thomas, trying to understand here... Why this place for the signal
initialization? Wouldn't InitPostmasterChild() be a more logical place
as we
On Wed, Apr 25, 2018 at 6:23 PM, Thomas Munro
wrote:
> On Tue, Apr 24, 2018 at 7:37 PM, Michael Paquier wrote:
>> Thomas, trying to understand here... Why this place for the signal
>> initialization? Wouldn't InitPostmasterChild() be a more logical place
>> as we'd want to have this logic caugh
On Tue, Apr 24, 2018 at 7:37 PM, Michael Paquier wrote:
> I have been looking at the proposed set for Linux, and the numbers are
> here. By replaying 1GB worth of WAL after a pgbench run with the data
> folder on a tmpfs the recovery time goes from 33s to 28s, so that's a
> nice gain.
Thanks for
On Sat, Apr 21, 2018 at 12:25:27PM +1200, Thomas Munro wrote:
> Here's a new version, because FreeBSD's new interface changed slightly.
I have been looking at the proposed set for Linux, and the numbers are
here. By replaying 1GB worth of WAL after a pgbench run with the data
folder on a tmpfs th
Here's a new version, because FreeBSD's new interface changed slightly.
--
Thomas Munro
http://www.enterprisedb.com
0001-Use-signals-for-postmaster-death-on-Linux-v3.patch
Description: Binary data
0002-Use-signals-for-postmaster-death-on-FreeBSD-v3.patch
Description: Binary data
On Thu, Apr 19, 2018 at 6:20 PM, Andres Freund wrote:
> On April 18, 2018 8:05:50 PM PDT, Thomas Munro
> wrote:
>>By the way, these patches only use the death signal to make
>>PostmasterIsAlive() fast, for use by busy loops like recovery. The
>>postmaster pipe is still used for IO/timeout loops
On April 18, 2018 8:05:50 PM PDT, Thomas Munro
wrote:
>On Wed, Apr 18, 2018 at 5:04 PM, Thomas Munro
> wrote:
>> On Wed, Apr 11, 2018 at 10:22 PM, Heikki Linnakangas
> wrote:
On Tue, Apr 10, 2018 at 12:53 PM, Andres Freund
>
wrote:
> That person said he'd work on adding an equival
On Wed, Apr 18, 2018 at 5:04 PM, Thomas Munro
wrote:
> On Wed, Apr 11, 2018 at 10:22 PM, Heikki Linnakangas wrote:
>>> On Tue, Apr 10, 2018 at 12:53 PM, Andres Freund
>>> wrote:
That person said he'd work on adding an equivalent of linux'
prctl(PR_SET_PDEATHSIG) to FreeBSD.
>
> Here is
On Wed, Apr 11, 2018 at 10:22 PM, Heikki Linnakangas wrote:
>> On Tue, Apr 10, 2018 at 12:53 PM, Andres Freund
>> wrote:
>>> That person said he'd work on adding an equivalent of linux'
>>> prctl(PR_SET_PDEATHSIG) to FreeBSD.
Here is an implementation of Andres's idea for Linux, and also for
pat
On Wed, Apr 11, 2018 at 10:22 PM, Heikki Linnakangas wrote:
> On 10/04/18 04:36, Thomas Munro wrote:
>> Just an idea, not tested: what about a reusable WaitEventSet with zero
>> timeout? Using the kqueue patch, that'd call kevent() which'd return
>> immediately and tell you if any postmaster deat
On 10/04/18 04:36, Thomas Munro wrote:
On Tue, Apr 10, 2018 at 12:53 PM, Andres Freund wrote:
I coincidentally got pinged about our current approach causing
performance problems on FreeBSD and started writing a patch. The
problem there appears to be that constantly attaching events to the read
On April 9, 2018 6:57:23 PM PDT, Alvaro Herrera wrote:
>Andres Freund wrote:
>>
>> On April 9, 2018 6:31:07 PM PDT, Alvaro Herrera
> wrote:
>
>> >Would it work to use this second pipe, to which each child writes a
>> >byte that postmaster never reads, and then rely on SIGPIPE when
>> >postmaste
Andres Freund wrote:
>
> On April 9, 2018 6:31:07 PM PDT, Alvaro Herrera
> wrote:
> >Would it work to use this second pipe, to which each child writes a
> >byte that postmaster never reads, and then rely on SIGPIPE when
> >postmaster dies? Then we never need to do a syscall.
>
> I'm not follo
On April 9, 2018 6:36:19 PM PDT, Thomas Munro
wrote:
>On Tue, Apr 10, 2018 at 12:53 PM, Andres Freund
>wrote:
>> I coincidentally got pinged about our current approach causing
>> performance problems on FreeBSD and started writing a patch. The
>> problem there appears to be that constantly at
On Tue, Apr 10, 2018 at 12:53 PM, Andres Freund wrote:
> I coincidentally got pinged about our current approach causing
> performance problems on FreeBSD and started writing a patch. The
> problem there appears to be that constantly attaching events to the read
> pipe end, from multiple processes
On April 9, 2018 6:31:07 PM PDT, Alvaro Herrera wrote:
>Andres Freund wrote:
>
>> Another approach, that's simpler to implement, is to simply have a
>> second selfpipe, just for WL_POSTMASTER_DEATH.
>
>Would it work to use this second pipe, to which each child writes a
>byte
>that postmaster nev
Andres Freund wrote:
> Another approach, that's simpler to implement, is to simply have a
> second selfpipe, just for WL_POSTMASTER_DEATH.
Would it work to use this second pipe, to which each child writes a byte
that postmaster never reads, and then rely on SIGPIPE when postmaster
dies? Then we
Hi,
On 2018-04-05 12:20:38 -0700, Andres Freund wrote:
> > While it's not POSIX, at least some platforms are capable of delivering
> > a separate signal on parent process death. Perhaps using that where
> > available would be enough of an answer.
>
> Yea, that'd work on linux. Which is probably
Greetings,
* Heikki Linnakangas (hlinn...@iki.fi) wrote:
> On 06/04/18 19:39, Andres Freund wrote:
> >On 2018-04-06 07:39:28 -0400, Stephen Frost wrote:
> >>While I tend to agree that it'd be nice to just make it cheaper, that
> >>doesn't seem like something that we'd be likely to back-patch and I
On 06/04/18 19:39, Andres Freund wrote:
On 2018-04-06 07:39:28 -0400, Stephen Frost wrote:
While I tend to agree that it'd be nice to just make it cheaper, that
doesn't seem like something that we'd be likely to back-patch and I tend
to share Heikki's feelings that this is a performance regressi
Hi,
On 2018-04-06 07:39:28 -0400, Stephen Frost wrote:
> While I tend to agree that it'd be nice to just make it cheaper, that
> doesn't seem like something that we'd be likely to back-patch and I tend
> to share Heikki's feelings that this is a performance regression we
> should be considering fi
Greetings,
* Andres Freund (and...@anarazel.de) wrote:
> On 2018-04-05 14:39:27 -0400, Tom Lane wrote:
> > Andres Freund writes:
> > > ISTM the better approach would be to try to reduce the cost of
> > > PostmasterIsAlive() on common platforms - it should be nearly free if
> > > done right.
> >
On Thu, Apr 05, 2018 at 02:39:27PM -0400, Tom Lane wrote:
> While it's not POSIX, at least some platforms are capable of delivering
> a separate signal on parent process death. Perhaps using that where
> available would be enough of an answer.
Are you referring to prctl here?
+1 on improving per
On 2018-04-05 14:39:27 -0400, Tom Lane wrote:
> Andres Freund writes:
> > ISTM the better approach would be to try to reduce the cost of
> > PostmasterIsAlive() on common platforms - it should be nearly free if
> > done right.
>
> +1 if it's doable.
>
> > One way to achieve that would e.g. to st
Andres Freund writes:
> ISTM the better approach would be to try to reduce the cost of
> PostmasterIsAlive() on common platforms - it should be nearly free if
> done right.
+1 if it's doable.
> One way to achieve that would e.g. to stop ignoring SIGPIPE and instead
> check for postmaster death i
Hi,
On 2018-04-05 10:23:43 +0300, Heikki Linnakangas wrote:
> Profiling that, without any patches applied, I noticed that a lot of time
> was spent in read()s on the postmaster-death pipe, i.e. in
> PostmasterIsAlive(). We call that between *every* WAL record.
> That seems like an utter waste of
On 5 April 2018 at 08:23, Heikki Linnakangas wrote:
> That seems like an utter waste of time. I'm almost inclined to call that a
> performance bug. As a straightforward fix, I'd suggest that we call
> HandleStartupProcInterrupts() in the WAL redo loop, not on every record, but
> only e.g. every 3
Heikki Linnakangas wrote:
> That seems like an utter waste of time. I'm almost inclined to call that a
> performance bug. As a straightforward fix, I'd suggest that we call
> HandleStartupProcInterrupts() in the WAL redo loop, not on every record, but
> only e.g. every 32 records. That would make
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