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  1. WiredTiger
  2. WT-1439

exponential dhandle list traversal

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    • Type: Task
    • Status: Closed
    • Resolution: Fixed
    • Affects Version/s: None
    • Fix Version/s: None
    • Component/s: None
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      Description

      When opening a statistics cursor over a lot of tables we end up with exponentially worse performance. See SERVER-16353. The problem is that all time is spent in wt_session_get_btree traversing the dhandle list due to *wt_conn_btree_apply. 1000 tables takes 8 seconds, 3000 tables takes 84 seconds. As we open N tables, it loops in __wt_session_get_btree N+sum(1-N) times or N+(N(N+1)/2). For the 1000th open we are in that loop 501500 times, for the 3000th open we are in it 4504500 times for that one open_cursor call.

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              • Assignee:
                Unassigned
                Reporter:
                sue.loverso Sue LoVerso
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