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  1. Core Server
  2. SERVER-38341

Remove Parallel Batch Writer Mutex

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    Details

    • Type: Task
    • Status: Open
    • Priority: Major - P3
    • Resolution: Unresolved
    • Affects Version/s: None
    • Fix Version/s: Backlog
    • Component/s: Replication, Storage
    • Labels:
      None

      Description

      Currently here is my understanding of the PBWM:

      • Primaries take it in IS for all reads and writes. This is unnecessary because it will never conflict with anything
      • Secondaries take it in X around a batch
      • Secondary oplog appliers don't take it at all
      • Snapshot secondary readers never take it
      • Secondary readers only take it in IS if there is no lastApplied to read from

      The lock is only really used to serialize the second and fifth bullets above. It should be fairly straightforward to always have a lastApplied value to read from on secondaries. This extra lock adds a lot of code complexity with very little value and is high value code cleanup.

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          depends on

          Bug - A problem which impairs or prevents the functions of the product. SERVER-44105 Perform ShardServerCatalogLoader writes in a single transaction

          • Major - P3 - Major loss of function.
          • Open
          is depended on by

          Bug - A problem which impairs or prevents the functions of the product. SERVER-41010 getMinValid() in bgsync shouldn't conflict with PBWM lock

          • Major - P3 - Major loss of function.
          • Open
          is related to

          Improvement - An improvement or enhancement to an existing feature or task. SERVER-26006 Audit all background tasks and decide which should conflict with replication application

          • Major - P3 - Major loss of function.
          • Closed
          related to

          Bug - A problem which impairs or prevents the functions of the product. SERVER-44821 retrieving storage stats for currentOp blocked by slow oplog application

          • Major - P3 - Major loss of function.
          • Closed

          Bug - A problem which impairs or prevents the functions of the product. SERVER-44859 plan_cache_index_create.js is blocked on two phase index build commit

          • Major - P3 - Major loss of function.
          • Closed

          Bug - A problem which impairs or prevents the functions of the product. SERVER-44943 avoid taking the PBWM lock in ReplicationCoordinatorExternalStateImpl::oplogExists()

          • Major - P3 - Major loss of function.
          • Closed

          Bug - A problem which impairs or prevents the functions of the product. SERVER-44944 avoid taking the PBWM lock in SessionsCollectionRS::_isStandaloneOrPrimary()

          • Major - P3 - Major loss of function.
          • Closed

          Bug - A problem which impairs or prevents the functions of the product. SERVER-45007 PBWM acquisition in GlobalLock constructor ignores deadline

          • Major - P3 - Major loss of function.
          • Closed

          Task - A task that needs to be done. SERVER-41407 Create a test suite that does secondary reads and also kills secondaries

          • Major - P3 - Major loss of function.
          • Open

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                Dates

                • Created:
                  Updated: