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  1. Core Server
  2. SERVER-21107

Improve protocol version 1 replication throughput

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    • Type: Icon: Improvement Improvement
    • Resolution: Done
    • Priority: Icon: Critical - P2 Critical - P2
    • None
    • Affects Version/s: None
    • Component/s: Replication, Storage
    • Labels:
      None
    • Fully Compatible
    • Repl B (10/30/15), Repl C (11/20/15), Repl D (12/11/15)
    • 0

      On secondaries in PV1, replicated writes require waiting for journaling before updating their oplog position, for correctness. This change has caused performance and throughput to drop relative to the old PV0 replication process, as show below when PV1 became the default for replica sets.

      Version, Primary inserts/s, Secondary inserts/s, Ratio

      3.1.8        101790 / 259431 = 39.23%
git 21c6a57  100623 / 260348 = 38.64%
git c101632  111042 / 272315 = 40.77%
git bf22ad1   105979 / 268666 = 39.44%
[SERVER-20438: Stash pointer to _uncommittedRecordIds to get O(1) delete]
git 92e38e6  100365 / 306215 = 32.77%
git 0c001db   92363 / 324666 = 28.44%
git 3f273cf    98546 / 328241 = 30.02%
[Apply oplog and record in oplog concurrently]
git 3937e8   130399 / 326500 = 39.93%
git ca4481c  125779 / 333166 = 37.75%
git 1cd101f 129144 / 334833 = 38.56%
[New replica set configurations have protocolVersion=1 by default]
git d789bca 84857 / 338166 = 25.09%
git 4372e7b  81938 / 334853 = 24.47%
[REVERT: Apply oplog and record in oplog concurrently]
git f25e8ac   60469 / 335713 = 18.01%
git 32844e3 62481 / 324500 = 19.25%

3.1.9         61854 / 334666 = 18.48%

3.2.0-rc0     83754 / 326486 = 25.65%

        1. benchRun
          2 kB
          Martin Bligh
        2. benchSet
          0.6 kB
          Martin Bligh
        3. md_exec
          0.7 kB
          Martin Bligh
        4. md_rs2
          0.5 kB
          Martin Bligh
        5. pymongo_init_rs
          0.7 kB
          Martin Bligh

            Assignee:
            matt.dannenberg Matt Dannenberg
            Reporter:
            martin.bligh Martin Bligh
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              Created:
              Updated:
              Resolved: