Granted lock never released #115

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1. madelson commented on Dec 22, 2021

   

   madelson

   on Dec 22, 2021

   Last edited by madelson

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   Hi @gtaylor44 thanks for reporting. Without more information it is going to be difficult to investigate the issue.

   In this situation, I can think of several possible options:

   • The handle is never getting disposed
   • TryAcquire is throwing after acquiring the lock so the handle never gets created to release it
   • Disposing of the handle is failing/not working for some reason
   • TryAcquire is returning null for some reason despite having acquired the lock

   To start, it would be great to add some logging to your code so that we can start to narrow this down (perhaps you've already done this).

   var guid = Guid.NewGuid();
   Log($"Acquiring {myLock.Name} {guid}");
   using (var handle = await myLock.TryAcquireAsync(TimeSpan.FromHours(1)))
   {
       if (handle != null)
       {
           Log($"Acquired {myLock.Name} {guid}");
   
           ...
   
           Log($"Releasing {myLock.Name} {guid}");
       }
       else { Log($"Failed to acquire {myLock.Name} {guid}");
   }
   if (guid.HasValue) { Log($"Released {myLock.Name} {guid}"); }
   

   Also, can you confirm that you're seeing this behavior with the newest version of the library?
2. gtaylor44 commented on Dec 22, 2021

   

   gtaylor44

   on Dec 22, 2021

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   Thanks @madelson

   I will add some additional logging. It's only happened twice in the last year and this process is run every 15 minutes.

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3. gtaylor44 commented on Dec 22, 2021

   

   gtaylor44

   on Dec 22, 2021

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   @madelson

   I'm currently on version 2.1.0

   The last time I updated was when I first encountered this issue. I will update to 2.3.0 in the meantime.

   👍React with 👍1Reacted by madelson
4. madelson commented on Dec 23, 2021

   

   madelson

   on Dec 23, 2021

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   It's only happened twice in the last year and this process is run every 15 minutes.

   Wow I guess we might we waiting a long time for a repro, then. I wonder if it could be reproduced more quickly by a unit test acquiring and releasing in a tight loop.

   Can you tell me more about your setup?

   • How many threads/processes are typically contending for the lock?
   • Is it common for Acquire to block or is there usually no contention?
   • How long does each thread hold the lock for before releasing it?
   • Have you tried releasing locks asynchronously using await using?
5. madelson commented on Nov 6, 2022

   

   madelson

   on Nov 6, 2022

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   @gtaylor44 any chance you've seen this come up again?