[GitHub] [incubator-doris] HappenLee commented on pull request #3666: Del some useless code and impove the performance of sort

[GitBox]

HappenLee commented on pull request #3666:
URL: https://github.com/apache/incubator-doris/pull/3666#issuecomment-632982262


   @chaoyli 
   OK！This is performance result.
   
   ### ENV
   
      CPU : Intel(R) Xeon(R) CPU E5-2620 v2 @ 2.10GHz 6cores * 2 
      RAM : 96GB
   
   ### Data
   Random numbers from 1 to 50 million
   
   ### Test Result
   
   Order of arrangement | origin |  find_the_median | Percentage increase
   :--:|:--:|:--:|:--:
   Order | 41s985ms | 39s389ms | 6.18%
   Reverse | 36s854ms | 34s376ms | 6.67%
   Random Shuffle |36s520ms | 33s888ms | 7.2%
   
   Now Doris's optimizer is not powerful enough. I test the scenario where the 
order by column  cardinality is small and the repetition rate is high. If we 
can Intelligently choose  three way quick sort, there will be five to ten times 
better performance. What a pity.
   
   
   
   
   


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