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3003135 - Trace flags 364 and 16982 are available for tuning suboptimal query plan having skew data in join columns - SAP ASE

Symptom

  • A join query joining involving two or more tables is slow due to a suboptimal query plan. 
  • There exists another faster query plan using a different index or different join order.
  • There exists join column with skew data, a related column histogram in optdiag output shows ‘Total density’ is much higher than ‘Range cell density’, e.g.

    Statistics for column:                  "column_name"          
    Range cell density:             0.0001233381992404           
    Total density:                     0.3222680491657743


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Environment

  • SAP Adaptive Server Enterprise (ASE) 15.7
  • SAP Adaptive Server Enterprise (ASE) 16.0

Keywords

suboptimal query plan, CR 727887, 727887, Range cell density, Total density, trace flag 364, trace flag 16982

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, KBA , BC-SYB-ASE , Sybase ASE Database Platform (non Business Suite) , Product Enhancement

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