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  1. Apache Avro
  2. AVRO-2396

Huge performance regression on SpecificDatumReader for array reading



    • Type: Bug
    • Status: Resolved
    • Priority: Blocker
    • Resolution: Fixed
    • Affects Version/s: 1.9.0
    • Fix Version/s: 1.9.1
    • Component/s: csharp
    • Labels:


      The company where I'm working as a .NET developer is using Avro format for message.

      Recently, after upgrade to 1.9.0-rc2 and 1.9.0-rc4, there is a hug regression the read array object.

      Our test case reads a ETP defined object "Energistics.Datatypes.ChannelData" inside which contains 5000 dataitems, with previous avro version, it only took 300~ms to read the data, which with the last version it wooks 1+ min. (the protocol can found from https://www.energistics.org/etp-developers-users/)


      After look through the code, I find that should be caused by a change in SpecificRecordAccess class

      public object CreateRecord(object reuse)

      { return reuse ?? ObjectCreator.Instance.New(typeName, Schema.Type.Record); }

      Here, the reuse is null, thus ObjectCreator.Instance.New is run 5000 times and each time use reflection to get specific types.


      the previously version only do it in constructor:

      private class SpecificRecordAccess : RecordAccess
      private ObjectCreator.CtorDelegate objCreator;

      public SpecificRecordAccess(RecordSchema readerSchema)

      { objCreator = GetConstructor(readerSchema.Fullname, Schema.Type.Record); }

      public object CreateRecord(object reuse)

      { return reuse ?? objCreator(); }



      I'm trying to make a workaround and pass a reuse object in method public T Read(T reuse, Decoder decoder), but still not working since the SpecificDatumReader doesn't pass it through in below method.

      public void AddElements( object array, int elements, int index, ReadItem itemReader, Decoder decoder, bool reuse, object reuseobj)
      var list = (IList)array;
      for (int i=0; i < elements; i++)

      { list.Add( itemReader(null, decoder ) ); }





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              • Assignee:
                blachniet Brian Lachniet
                wangyingmm wangying
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