Interesting Project Re-Attachment Behavior
12 Feb 2007 16:52:43 UTC
Topic 192420
(moderation:
Like everyone else I was seeing anomalous behavior on one of my hosts. Strangely, my other 2 Einstein hosts were doing just fine. I had a completed result that seemed to just sit there and I didn't get any new work for two days. I updated. I reset. Finally I detached. I then noticed on the web site that the result had been sent and credited 2 days previously, but my host didn't know that...sigh. I did all this on 9 Feb.
Detaching when there are server problems wasn't the smartest thing I ever did :-) Of course I tried to reattach, but I couldn't do it until today. The attach finally worked and I got new work. What I found strange was that I had the same host number I had before (714160).
I presume the server was in la-la land for a few days so it probably didn't know I had detached. Getting the old host number certainly isn't a problem for me, but I mention this in case this has other consequences in the database. It's not what I expected to happen.
Interesting Project Re-Attachment Behavior
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Have a read of this thread and it might help explain the "anomalous" behaviour.
Why do you think this is strange?? When you detach you don't destroy the configuration information that resides on your host. If you had other projects running, you wouldn't even uninstall BOINC. Even if you did uninstall BOINC, this doesn't remove the files associated with each project. You could come back a month later, reinstall BOINC (using the same installation folder), re-attach to the project and fully expect to see the same host ID unless you have manually removed the project files.
Nope - no problem for the database.
Cheers,
Gary.
RE: Why do you think this
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I only mentioned it as strange because whenever I have detached on other projects I got a new host number when I reattached. I took this to be normal BOINC behavior. I'm glad that it's not a problem.
RE: ... whenever I have
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Actually, you may be correct. In December last, I mothballed a large number of machines by setting "No new tasks" and then "Suspending" the project, but not actually "Detaching" as well. I had thought I had detached but on rechecking a couple of them, the project was only suspended. I've "Resumed" these pair of machines and they have simply continued to use their previous IDs. So I can't say for sure if "Detaching" actually deletes the project specific information from the state file, "client_state.xml", where the hostID is stored for each project.
If you have observed the behaviour of losing the ID by detaching, that would probably occur by the deletion of the appropriate section of the state file. I could imagine that this deletion might be prevented if something else had the state file open or locked at the time of attempted deletion.
Whatever the precise cause, I'm sure the behaviour is benign as far as the database is concerned.
Cheers,
Gary.
RE: RE: Why do you think
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It was the normal behavior in the past, and still is common behavior. However there have been improvements to the section of the server that recognizes previously attached hosts. So while it is still likely that you will get a new host ID from detaching and reattaching the odds have been reduced.
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