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  1. Core Server
  2. SERVER-4243

If there is a pending write due to an fsync lock, all reads are blocked

    Details

    • Type: Bug
    • Status: Closed
    • Priority: Minor - P4
    • Resolution: Fixed
    • Affects Version/s: 2.0.1
    • Fix Version/s: 2.2.0
    • Component/s: Concurrency
    • Labels:
      None
    • Environment:
      64bit Ubuntu 11.04 + gcc 4.5.2
    • Operating System:
      Linux

      Description

      By locking the database and issuing a single write, all readers are starved. No read operations can go through.

      Because of this, a new shell will start but cannot be used – it must be doing some read-lock requiring operation. Ostensibly, this is due to the shell attempting to read but being unable to do so due to the waiting write starving any reader attempt.

      Issuing "mongo --eval 'db.fsyncUnlock()'" will unlock the database, allow writes through, and unfreeze the shell.

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                • Created:
                  Updated:
                  Resolved: