Writing transaction oplog entries must not take locks while holding an oplog slot

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    • Type: Bug
    • Resolution: Fixed
    • Priority: Major - P3
    • 4.1.11
    • Affects Version/s: None
    • Component/s: Replication
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    • Fully Compatible
    • ALL
    • Repl 2019-04-22, Repl 2019-05-06, Repl 2019-05-20
    • 30
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    • 3
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      It is illegal to acquire new locks while holding open an oplog slot, since it can cause the deadlock described in SERVER-35367. We do this in a few places when writing transaction oplog entries:

      When preparing a transaction, we reserve oplog slots here or here, then stash the locker here or here, then take a global lock here or here.

      When aborting a prepared transaction, we reserve an oplog slot here, then release locks here, then take a global lock here.

      When committing a prepared transaction, we reserve an oplog slot here, then release locks here, then take a global lock here.

      (Note that the global lock acquisition for writing oplog entries for unprepared transaction commit is not a problem, since the locker is already holding the global lock.)

              Assignee:
              Siyuan Zhou
              Reporter:
              Tess Avitabile (Inactive)
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                Created:
                Updated:
                Resolved: