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  1. HPCC
  2. HPCC-14545

Super file locking can hold locks for too long whilst trying to gain others

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    Details

    • Type: Improvement
    • Status: Accepted
    • Priority: Major
    • Resolution: Unresolved
    • Affects Version/s: None
    • Fix Version/s: None
    • Component/s: DFS
    • Labels:
      None
    • Compatibility:
      Minor

      Description

      Super file transactions actions attempt to lookup and lock files during a 'prepare' phase. As part of that preparation some files will attempt to be exclusively locked (so as changed).
      If any those exclusive locks can't be serviced immediately, the action will fail, the transaction unlocks all files and sleeps to retry.

      This works well when there is write-lock contention at the commit stage, but it should also behave the same way for any lookup which might block, due to contention.

      Otherwise the effect of a action prepare step blocking whilst attempting to lookup file, whilst holding previously successful action prepare step file locks, is to block other workunits from progressing.

      Any file lookup that can block due to locking contention should behave the same was as the change to an exclusive lock in preparation for change, i.e. if the lock cannot be made without contention, the action should fail and the transaction should pause and retry.

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            • Assignee:
              mckellyln Mark Kelly
              Reporter:
              jakesmith Jake Smith
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              Dates

              • Created:
                Updated: