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  1. Qt
  2. QTBUG-100292

Qt6's QSET very slow

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Details

    • Bug
    • Resolution: Duplicate
    • Not Evaluated
    • None
    • 6.2.2
    • Core: Other
    • None
    • Linux/X11

    Description

      This is the stacktrace:

      It takes ages when I try to do set difference with - operator, when sets have around 10000 items both. It spends ages in 1+2 functions of stacktrace.

      Same code works 100000x faster with Qt 5.

      1   QHashPrivate::Data<QHashPrivate::Node<QString, QHashDummyValue>>::erase    qhash.h                664 0x7ffff7797e35 
2   QHash<QString, QHashDummyValue>::remove                                    qhash.h                885 0x7ffff7797b54 
3   QSet<QString>::remove                                                      qset.h                 99  0x7ffff779753d 
4   QSet<QString>::subtract                                                    qset.h                 317 0x7ffff779737f 
5   QSet<QString>::operator-=                                                  qset.h                 226 0x7ffff778c8e1 
6   QSet<QString>::operator-                                                   qset.h                 235 0x7ffff7846a69

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          duplicates

          Bug - A problem which impairs or prevents the functions of the product. QTBUG-91739 Performance regression on QHash::insert() and QHash::remove()

          • P1: Critical - Urgent and Important, will STOP the release if matched with set FixVersion field. This includes regressions from the last version that are not edge cases; Data loss; Build issues; All but the most unlikely crashes/lockups/hanging; Serious usability issues and embarrassing bugs & Bugs critical to a deliverable. This is the highest possible priority for requirements.
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              thiago Thiago Macieira
              skunkos Martin Rotter
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              Dates

                Created:
                Updated:
                Resolved:

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