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  1. Core Server
  2. SERVER-4143

Replication should pause during fsync+lock

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    Details

    • Type: Improvement
    • Status: Closed
    • Priority: Major - P3
    • Resolution: Gone away
    • Affects Version/s: None
    • Fix Version/s: None
    • Component/s: Concurrency, Replication
    • Labels:

      Description

      While a secondary is locked, replication attempts to get the write lock on the secondary. This causes future readers to block, since the write lock takes precedence, but readers ought to be able to proceed since the writer won't be unblocked soon.

      A potential workaround: Instead of blocking on the lock, fsync+lock on a secondary could simply pause the replication process (probably pausing the oplog reader and not take out the lock) and after writes have finished then flush all database files to get a consistent file system state.

      More likely workaround: wait for SERVER-1423 to be completed, in which case we'll get the correct behavior for free: readers will proceed even while writers are queued waiting for fsyncUnlock.

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          depends on

          New Feature - A new feature of the product, which has yet to be developed. SERVER-3950 Add a command to stop/restart replication

          • Minor - P4 - Minor loss of function, or other problem where easy workaround is present.
          • Closed

          Improvement - An improvement or enhancement to an existing feature or task. SERVER-1423 reads often aren't possible while in fsync and lock mode

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

          Bug - A problem which impairs or prevents the functions of the product. SERVER-4123 fsync/lock blocks the progress of mongodump

          • Major - P3 - Major loss of function.
          • Closed
          is duplicated by

          Bug - A problem which impairs or prevents the functions of the product. SERVER-5454 backups using fsync from secondaries freeze chained secondary replication

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

            Activity

              People

              Assignee:
              backlog-server-repl Backlog - Replication Team
              Reporter:
              redbeard0531 Mathias Stearn
              Participants:
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                Dates

                Created:
                Updated:
                Resolved: