Обсуждение: Re: [PERFORM] Hanging queries on dual CPU windows

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Re: [PERFORM] Hanging queries on dual CPU windows

От
"Magnus Hagander"
Дата:
> > > Looking a my system while testing this it still loooked
> like it was
> > > hanging on that plac ein the code, even though I saw no
> problems. So
> > > I'm not convinced we can actually trust the stacktrace from the
> > > non-default threads. So I don't think this patch will
> actually work
> > > :-( But it's worth a try.
> >
> > I'm afraid you're right. Hangs again :(
>
> I now have the toolchain set up, so if you want me to try
> stuff, please let me know. Resolving this is important to us.

Great. That'll certainly help - now you don't have to wait for binaries
from me.

What I'd be interested in seeing is new stackdumps from a version where
you:
1) Do *not* have the patch for mutexes applied
2) Have removed "static" from all the function devlarations in signal.c
and socket.c, bnoth in src/backend/port/win32.

If you can, it'd be interesting to see it from the pre-SP1 install as
well - once it hangs.


> On a whim, I replaced InitializeCriticalSection with
> InitializeCriticalSectionAndSpinCount, since MSDN told me
> that would be better for SMP. No joy.

No, that should make no difference - except possibly a tiny difference
in speed.


Do you have the ability to test 8.0 on the same machine? We did some
extensive modifications to the signal stuff between 8.0 and 8.1, it'd be
interesting to see if that changed things.

//Magnus


Re: [PERFORM] Hanging queries on dual CPU windows

От
"Merlin Moncure"
Дата:
> Do you have the ability to test 8.0 on the same machine? We did some
> extensive modifications to the signal stuff between 8.0 and 8.1, it'd be
> interesting to see if that changed things.

I had very similar behavior some weeks back on a machine that had not
been upgraded to 8.1.  It was a dual opteron on win2k server.  Some
simple queries (select 1 + 2) would work ok but anything that did real
work on tables would hang and the backend would not respond to
signals.  Only recourse was to end task from task mgr which cycled the
entire server with no data loss.

This may or may not be the same problem but it sounds similar.

Unfortunately the problem was extremely time sensitive and I could not
play with it much.  However, since this is pre-8.1 this argues against
Qingqing's signal changes (maybe).  I've since moved on to a linux
environment so my win32 contributions will diminish greatly :)

merlin


Re: [PERFORM] Hanging queries on dual CPU windows

От
Jan de Visser
Дата:
On Monday 13 March 2006 12:27, Magnus Hagander wrote:
> Great. That'll certainly help - now you don't have to wait for binaries
> from me.
>
> What I'd be interested in seeing is new stackdumps from a version where
> you:
> 1) Do *not* have the patch for mutexes applied
> 2) Have removed "static" from all the function devlarations in signal.c
> and socket.c, bnoth in src/backend/port/win32.

I did that, and the interesting thing is that:
1. It takes much longer to hang.
2. Once it hangs, the stacktraces are the same.
3 (and this is the kicker). The thing starts working again after a couple (+/-
5) minutes ?????????

1. can probably be explained by the fact that I didn't compile with any
optimization. Can you tell me what CFLAGS the binary distro uses? 2. I don't
know (are there other tools I can use?), and 3. I frankly don't understand. I
know for sure that with the stock 8.1.3 it would not revive itself (I let it
running for a *long* time).

>
> If you can, it'd be interesting to see it from the pre-SP1 install as
> well - once it hangs.

I've never seen a pre-SP1 install hang.

>
> > On a whim, I replaced InitializeCriticalSection with
> > InitializeCriticalSectionAndSpinCount, since MSDN told me
> > that would be better for SMP. No joy.
>
> No, that should make no difference - except possibly a tiny difference
> in speed.
>
>
> Do you have the ability to test 8.0 on the same machine? We did some
> extensive modifications to the signal stuff between 8.0 and 8.1, it'd be
> interesting to see if that changed things.

I seem to remember we made ourselves dependend on 8.1 somehow, but will check.

jan




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Jan de Visser                     jdevisser@digitalfairway.com

                Baruk Khazad! Khazad ai-menu!
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