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  1. Qt
  2. QTBUG-82268

Multi-Threaded program - slow qTzSet calls in QDateTime

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Details

    • Suggestion
    • Resolution: Unresolved
    • P3: Somewhat important
    • None
    • 5.10.1
    • Core: Date/Time
    • None
    • All

    Description

      Hi,

      I use QOCI to request data from Oracle. When i fetch a much data (4000 rows), Qt take 40% of time in futex . 

      I investiguated and i see in qtcode/qdatetime.cpp, qTzSet() is called every row fetched (because i have a date type column) and just after localtime_r is called.

      qTzSet is thread safe. Qt have a mutex lock and glibc also has => it's bad performance for many calls and many concurrents threads..

      Is not necessary for me to refresh timezone every row. I export TZ environment variable before start program.

      It's possible to envisage a variable macro to configure if we want refresh timezone or no when we are in multithread environnement ?

       

      Thx.

       

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          relates to

          Bug - A problem which impairs or prevents the functions of the product. QTBUG-75585 Massive performance regression in QML Date object

          • 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.
          • Closed

          Task - A task that needs to be done. QTBUG-56899 Add a static QTimeZone method to refresh system zone information

          • P3: Somewhat important - Should be fixed, but doesn't affect the release in any way.
          • Open
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              Eddy Edward Welbourne
              abde13 abdennour boutrig
              Vladimir Minenko Vladimir Minenko
              Alex Blasche Alex Blasche
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                Updated:

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