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Hash segmentation

  • June 30, 2015
  • 2 replies
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deb0687
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Hi,

 

While creating projection we do segmented by hash (col1,col2).

 

What is the rule for taking which columns and how many columns  for better performance ?

 

Can I take all the columns or only the primary key column ?

 

Regards,

Deb

    2 replies

    SruthiA
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    • SruthiA
    • Participating Frequently
    • June 30, 2015

    HI,

     

     

            In a projection, the data to be hashed consists of one or more column values, Choose columns that have a large number of unique data values and acceptable skew in their data distribution. Primary key columns that meet the criteria could be an excellent choice for hash segmentation. For more information on Hash Segmentationm Please visit the link

     

    http://my.vertica.com/docs/7.1.x/HTML/index.htm#Authoring/AdministratorsGuide/ConfiguringTheDB/PhysicalSchema/DesigningForSegmentation.htm?Highlight=hash segmentation

     

     

    -Regards,

     Sruthi

    deb0687
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    • deb0687
    • Author
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    • July 2, 2015

    Thanks Sruthi.

     

    Can you plz make me understand , Whats the difference between High availability and Load balancing with a practical example.

     

     

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