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  1. Cassandra
  2. CASSANDRA-7545

Hints for a down node are written to a single partition in system.hints on the coordinator leading to contention

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    Details

    • Type: Bug
    • Status: Resolved
    • Priority: Normal
    • Resolution: Duplicate
    • Fix Version/s: None
    • Component/s: None
    • Labels:
      None
    • Severity:
      Normal

      Description

      The worst side effect is potentially orders of magnitude larger than suspected memory allocation due to a race condition updating the columns in the memtable (see CASSANDRA-7546)

      That said, having so many hints in a single partition has other negative side effects (non linear growth of sorted tree data structure overhead in memtable, just plain large number of tombstones in a row etc.)

      Ideally, the hints would be partitioned by both the nodeUUID, and a fixed number of (say 4) bits of a hash of the original rowmutation's partition key... even this small spreading of load has a significant improvement.

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            • Assignee:
              Unassigned Assign to me
              Reporter:
              graham sanderson graham sanderson

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                Updated:
                Resolved:

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