2257096 - SAP IQ16 SP10.7 : 'Union' Query caused error 'dfo.cxx .. Parallel Combiner'

During migration project, 'dfo.cxx .. Parallel Combiner' error is retured when executing select query
including union all. This error has been produced since applied SP10.7 which fixed some 'Union' issues.

 *  iqmsg & stack =>

      *****************************************************
      **
      **       Non-Fatal IQ Internal Error Detected
      **       at dflib/dfo.cxx:1969  on thread 1359 (TID 1350)
      **       with Query_Name: Error_2244_1969
      **       Error detected at DFO #401 Parallel Combiner
      ..
      .. StackTraceForThisThreadPKciS0_S0_S0_ ..
      .. df_ExceptionC1EPKciNS_df_ErrorCodeES1_S1_ ..
      .. df_Exception..ThrowExceptionEPKciNS_ ..
      .. dfo..ConstructWorkAllocatorInternal ..
      .. dfo..ConstructWorkAllocator ..
      .. dfo_Combiner..SourcePreFetchEv ..
      .. dfo_Combiner.FetchOpusEv ..
      .. dfo_FetchEv ..
      .. dfjo_Hash..Fetch_T2_IntoHashEv ..
      .. dfjo_Hash.ExecWorkERij ..
      .. workAllocator.DoWorkEj ..

SAP IQ 16.0

'dfo.cxx:1969' ; 'Parallel Combiner' ; 'dfo_Combiner..SourcePreFetch' ; 'dfo_Combiner.FetchOpus' ; , KBA , BC-SYB-IQ , Sybase IQ , Bug Filed