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  1. Qt
  2. QTBUG-20658

[Performance] QSqlQuery::boundValues has unneeded O(n^2) complexity, can be O(n)

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    • Icon: Bug Bug
    • Resolution: Done
    • Icon: P2: Important P2: Important
    • 5.0.0 Beta 1, 5.0.0
    • 4.7.3
    • SQL Support
    • None

      For each bound value a call is made to QSqlResult::private->indexes.index(QHash.index, which is O(n)), which results in overall complexity of O(n^2).

      For ORMs that select records by a list of primary or foreign keys this can end up taking much longer than needed.

      Attached patch makes the call O(n).

        1. qsqlquery_boundValues_speedup.diff
          3 kB
          Matthew Newell
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            zhongle honglei zhang
            newellm Matthew Newell
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              Created:
              Updated:
              Resolved:

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