[jira] [Created] (SPARK-15764) Replace n^2 loop in BindReferences

["Josh Rosen (JIRA)" <ji...@apache.org>]

Josh Rosen created SPARK-15764:
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             Summary: Replace n^2 loop in BindReferences
                 Key: SPARK-15764
                 URL: https://issues.apache.org/jira/browse/SPARK-15764
             Project: Spark
          Issue Type: Improvement
          Components: SQL
            Reporter: Josh Rosen
            Assignee: Josh Rosen


BindReferences contains a n^2 loop which causes performance issues when operating over large schemas: to determine the ordinal of an input, we perform a linear scan over the {{input}} array. Because {{input}} can sometimes be a List, the call to {{input(ordinal).nullable}} can also be O(n).

Instead of performing a linear scan, we can convert the input into an array and build a hash map to map from expression ids to ordinals. The greater up-front cost of the map construction is offset by the fact that an expression can contain multiple attribute references, so the cost of the map construction is amortized across a number of lookups.



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