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  1. WiredTiger
  2. WT-7191

Replace FNV hash with City hash

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    Details

    • Type: Improvement
    • Status: Closed
    • Priority: Major - P3
    • Resolution: Fixed
    • Affects Version/s: None
    • Fix Version/s: WT10.0.1, 4.4.7, 5.0.0-rc0
    • Component/s: None
    • Labels:
      None
    • Story Points:
      3
    • Sprint:
      Storage - Ra 2021-05-03

      Description

      Changing this line to use _wt_hash_city64 dropped the time spent in the hash function from 12% to 1.5% in a profile of phase 2 of index building (on a modified mongo tree using dictionary compression on a new index type). CityHash hashes 8 bytes at a time, while FNV hashes 1 byte at a time, so that improvement is in-line with expectations.

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            Assignee:
            etienne.petrel Etienne Petrel
            Reporter:
            redbeard0531 Mathias Stearn
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              Updated:
              Resolved: