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  1. Qt
  2. QTBUG-32720

QQmlPropertyMap bad performances at insertion

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    • 105d10dea9d790a69595a2e73e8fea80a5d1a3ad (qtbase)

    Description

      I ported an application from Qt4 to Qt5 and I have performance issues with QDeclarativePropertyMap/QQmlPropertyMap.

      The insertion time is way slower in Qt5.

      Test done with 500 insertions :

      QDeclarativePropertyMap on Qt4 : ELLAPSED TIME = 66 ms
      QDeclarativePropertyMap map;
QElapsedTimer timer;
timer.start();

for(int i=0; i < 500; i++) {
   map.insert(QString::number(i),QString::number(i));
}

qDebug() << "ELAPSED TIME : " << timer.elapsed();
      QDeclarativePropertyMap on Qt5 : ELLAPSED TIME = 2911 ms
      QDeclarativePropertyMap  map;
QElapsedTimer timer;
timer.start();

for(int i=0; i < 500; i++) {
    map.insert(QString::number(i),QString::number(i));
}

qDebug() << "ELAPSED TIME : " << timer.elapsed();
      QQmlPropertyMap on Qt5 : ELLAPSED TIME = 2922 ms
      QQmlPropertyMap map;
QElapsedTimer timer;
timer.start();

for(int i=0; i < 500; i++) {
    map.insert(QString::number(i),QString::number(i));
}

qDebug() << "ELAPSED TIME : " << timer.elapsed();

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          duplicates

          Bug - A problem which impairs or prevents the functions of the product. QTBUG-57792 QQmlPropertyMap inserting new properties is O(N^2)

          • P3: Somewhat important - Should be fixed, but doesn't affect the release in any way.
          • Closed
          For Gerrit Dashboard: QTBUG-32720
          # Subject Branch Project Status CR V
          73361,5 Fix quadratic behavior in QMetaObjectBuilder when writing string table stable qt/qtbase Status: MERGED +2 0

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              shausman Simon Hausmann
              x-krys Christopher Courtois
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              Dates

                Created:
                Updated:
                Resolved:

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