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why sort_columns?

Posted by 孙而焓 on May 15, 2017; 2:31am
URL: http://apache-carbondata-dev-mailing-list-archive.168.s1.nabble.com/why-sort-columns-tp12663.html

hi community,
   
since we already have many rmdb sqls scripts,we don't want to change them too much when migrating to carbon.
suppose we already have sql script like:
   "create table (c1,c2,...c7")",
If we want to change column order to shift most often used column ahead when query data,i think it's better change it this way like:
  "create table(c1,c2,c7,c4..c6,c3)
rather
  "create table(c1...c7) tblproperties('sort_columns' = 'c7,c3')"
because the former way just reordering columns without adding extra settings,which is more readable to thos who is familiar with rmdb but not with carbon.



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