Hiroshi Inoue 14cf61e909 [SPARK-16331][SQL] Reduce code generation time ... ## What changes were proposed in this pull request? During the code generation, a `LocalRelation` often has a huge `Vector` object as `data`. In the simple example below, a `LocalRelation` has a Vector with 1000000 elements of `UnsafeRow`. ``` val numRows = 1000000 val ds = (1 to numRows).toDS().persist() benchmark.addCase("filter+reduce") { iter => ds.filter(a => (a & 1) == 0).reduce(_ + _) } ``` At `TreeNode.transformChildren`, all elements of the vector is unnecessarily iterated to check whether any children exist in the vector since `Vector` is Traversable. This part significantly increases code generation time. This patch avoids this overhead by checking the number of children before iterating all elements; `LocalRelation` does not have children since it extends `LeafNode`. The performance of the above example ``` without this patch Java HotSpot(TM) 64-Bit Server VM 1.8.0_91-b14 on Mac OS X 10.11.5 Intel(R) Core(TM) i5-5257U CPU 2.70GHz compilationTime: Best/Avg Time(ms) Rate(M/s) Per Row(ns) Relative ------------------------------------------------------------------------------------------------ filter+reduce 4426 / 4533 0.2 4426.0 1.0X with this patch compilationTime: Best/Avg Time(ms) Rate(M/s) Per Row(ns) Relative ------------------------------------------------------------------------------------------------ filter+reduce 3117 / 3391 0.3 3116.6 1.0X ``` ## How was this patch tested? using existing unit tests Author: Hiroshi Inoue <inouehrs@jp.ibm.com> Closes #14000 from inouehrs/compilation-time-reduction.		2016-06-30 21:47:44 -07:00
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src	[SPARK-16331][SQL] Reduce code generation time	2016-06-30 21:47:44 -07:00
pom.xml	[SPARK-15290][BUILD] Move annotations, like @Since / @DeveloperApi, into spark-tags	2016-05-17 09:55:53 +01:00