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From "Jason Altekruse (JIRA)" <j...@apache.org>
Subject [jira] [Created] (DRILL-2702) Support more advanced constant expression folding
Date Mon, 06 Apr 2015 23:08:12 GMT
Jason Altekruse created DRILL-2702:
--------------------------------------

             Summary: Support more advanced constant expression folding
                 Key: DRILL-2702
                 URL: https://issues.apache.org/jira/browse/DRILL-2702
             Project: Apache Drill
          Issue Type: Improvement
          Components: Query Planning & Optimization
            Reporter: Jason Altekruse
            Assignee: Jinfeng Ni


A variety of constant expressions are now folded at planning time with the work completed
for DRILL-2060. One of the examples listed in the issue is not currently supported. Supporting
an expression re-write like this will require more work, this issue is here to track that
enhancement request. These types of rewrites are particularly useful for Drill because the
speed of Drill is often limited by the types of filter pushdowns supported by the underlying
storage system. For system that support range scans, we can rewrite inequalities to range
scans in simple cases. Currently we cannot re-write more complicated inequalities like this
one below, this query would prompt a full table scan with a filter, but the transformation
shown can turn it into a range scan.

Where age + 5 < 42
can be re-written as
Where age < 37



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