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  1. Documentation
  2. DOCS-7979

Size and count in collection stats are persisted during checkpoints in WiredTiger

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    • Type: Icon: Task Task
    • Resolution: Done
    • Priority: Icon: Major - P3 Major - P3
    • 01112017-cleanup
    • Affects Version/s: None
    • Component/s: manual
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      https://docs.mongodb.com/manual/reference/command/collStats/#unexpected-shutdown-and-count

      I reported some inaccurate information via DOCS-5682, saying that size and count is updated every 1000 document writes. As clarified in SERVER-24266, we update the in-memory cache every 1000 document writes, but the updates only become persistent when WiredTigerKVEngine::syncSizeInfo is called, most commonly every 60 seconds as part of WiredTigerKVEngine::haveDropsQueued.

      This means that number can drift much more in the event of an unclean shutdown (as much as 60 seconds worth of writes).

            Assignee:
            ravind.kumar Ravind Kumar (Inactive)
            Reporter:
            dan@mongodb.com Daniel Pasette (Inactive)
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              Created:
              Updated:
              Resolved:
              7 years, 36 weeks, 3 days ago