Shawn Lavelle created SPARK-19730:
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             Summary: Predicate Subqueries do not push results of subqueries to 
data source
                 Key: SPARK-19730
                 URL: https://issues.apache.org/jira/browse/SPARK-19730
             Project: Spark
          Issue Type: Bug
          Components: Optimizer, SQL
    Affects Versions: 2.1.0
            Reporter: Shawn Lavelle


When a SparkSQL query contains a subquery in the where clause, such as a 
predicate query using the IN operator, the results of that subquery are not 
pushed down as a fileter to the DataSourceAPI for the outer query. 

Example: 
Select point, time, value from data where time between now()-86400 and now() 
and point in (select point from groups where group_id=5);

Two queries will be sent to the data Source.  One for the subquery, and another 
for the outer query. The subquery works correctly returning the points in the 
group, however, outer query does not push a filter for point column.

Affect:
The "group" table has a few hundred rows to group a few hundred thousand 
points.  The data table has several billion rows keyed by point and time.  
Without the ability to push down the filters for the columns of outer the 
query, the data source cannot properly conduct its pruned scan.

The subquery results should be pushed down to the outer query as an IN Filter 
with the results of the subquery.



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