[jira] [Created] (TRAFODION-1914) optimize "added columns" in indexes

["Eric Owhadi (JIRA)" <ji...@apache.org>]

Eric Owhadi created TRAFODION-1914:
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             Summary: optimize "added columns" in indexes
                 Key: TRAFODION-1914
                 URL: https://issues.apache.org/jira/browse/TRAFODION-1914
             Project: Apache Trafodion
          Issue Type: Improvement
          Components: sql-cmp
            Reporter: Eric Owhadi


the current CREATE INDEX feature will always put each column added to the index in the clustering key. But sometimes, users just want to add columns to the index to avoid having to probe back the primary table to fetch just one or 2 column back. Instead copying these columns in the index can avoid making a probe back to main table and therefore improve performance. Current implementation allows this, but will always put the extra column as part of the clustering key. That is not optimal, and very bad for the case of VARCHAR, since they are exploded to there max size when part of the clustering key. So this JIRA is abount altering the syntax of create index, and flag columns that are added but should not be part of the clustering key.



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