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ed2353

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Message 48193 - Posted: 18 Feb 2014, 10:05:49 UTC

Several of my pnw tasks have a message I've never seen before.
"Scheduler wait: Waiting to acquire lock"

Do I have a problem, or is this another of the Server's problems?
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ed2353

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Message 48194 - Posted: 18 Feb 2014, 10:15:25 UTC - in response to Message 48193.  

It seems the problem was mine.
I exited BOINC manager completely, then restarted it.
All tasks are now running.

I am still interested to find an explanation though.
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Message 48195 - Posted: 18 Feb 2014, 10:18:13 UTC - in response to Message 48193.  

I spoke too soon!

When I finished typing the above and looked at Boinc manager again, the message had re-appeared on the same 9 PNW tasks.
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Message 48197 - Posted: 18 Feb 2014, 12:46:40 UTC - in response to Message 48195.  

The tasks restarted about 15 minutes after my last post.

I'd still like to know what this message was about.
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Profile Iain Inglis
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Message 48203 - Posted: 19 Feb 2014, 14:23:12 UTC

I haven't seen that warning before but googling the message suggests it's been around for a few years at least. Essentially, something has taken a lock on a file that BOINC wants, which is preventing BOINC starting properly. The cases that I saw described elsewhere seemed to be ones in which a crashed part of BOINC had failed to release a lock on a file that was needed later. If that's the case here then a reboot should fix it. If, however, something non-BOINC has locked the file then the usual candidates would be virus checkers and the various search indexers (though they don't usually hold locks for long). Excluding the BOINC application and data folders usually solves that kind of problem.
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Message 48204 - Posted: 19 Feb 2014, 15:53:34 UTC - in response to Message 48203.  

Thanks Iain.

My computer had just been recovered from an overnight crash when the message appeared, so there could have been something still around from the BOINC session that was running when the crash occurred. That could have caused the problem with the new session I started after the recovery reboot.

However, the lock was released after about 15 minutes, so it could have been a search index that had started after the recovery reboot, so I'll check that.

The main point I've learned is that it was a problem on my computer, not the BOINC PNW server.

Thanks again.
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Profile Thyme Lawn
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Message 48205 - Posted: 19 Feb 2014, 16:51:21 UTC - in response to Message 48204.  

The "Waiting to acquire lock" message is generated when BOINC detects that a second application is attempting to run in one of its slots. BOINC will continue trying to start the application every 10 minutes.

Technical details: when an application is running there's a lock on the file "boinc_lockfile" in the slot directory, and the detection is due to the file already being locked.

The only time I've seen that message was when the BOINC core client crashed and left orphaned applications running.
"The ultimate test of a moral society is the kind of world that it leaves to its children." - Dietrich Bonhoeffer
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Message 48206 - Posted: 20 Feb 2014, 1:13:32 UTC - in response to Message 48205.  

I've checked my indexing and BOINC was excluded, so indexing was not the problem. My ZoneAlarm A/V has never caused a problem in the past, so that is unlikely.

Because BOINC was not shut down properly when my computer crashed, I guess it left some orphans running. That would match with the only time you've seen that message, so is probably the reason for me seeing it too. When I checked the timing more carefully, it was around 10 minutes, not 15 when the tasks restarted, so that seems to confirm your explanation.

Thanks for your answer.
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Profile JIM

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Message 48207 - Posted: 20 Feb 2014, 4:54:24 UTC - in response to Message 48205.  

The only time I've seen that message was when the BOINC core client crashed and left orphaned applications running.


In this situation the best way to stop these orphan processes is by using Task Manager. To open it just press the ctrl, alt, and delete keys together. Clicking on the processes tab shows all running processes. You can then manually stop any still running processes.

I have used this occasionally while making backups when the boinc_lock file hangs open after exiting the manager.

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Message boards : Number crunching : Scheduler wait

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