Github user chenghao-intel commented on a diff in the pull request:
https://github.com/apache/spark/pull/1238#discussion_r14544542
--- Diff:
sql/core/src/main/scala/org/apache/spark/sql/execution/SparkStrategies.scala ---
@@ -61,8 +61,6 @@ private[sql] abstract class SparkStrategies extends
QueryPlanner[SparkPlan] {
condition.map(Filter(_,
broadcastHashJoin)).getOrElse(broadcastHashJoin) :: Nil
}
- def broadcastTables: Seq[String] =
sqlContext.joinBroadcastTables.split(",").toBuffer
-
def apply(plan: LogicalPlan): Seq[SparkPlan] = plan match {
--- End diff --
I think this probably has 2 rules for size estimated JOIN if I understand
correctly:
* if size estimates less than a threshold, we can convert it into a
BroadcastNestedLoopJoin
* In equi-join(InnerJoin), if the left estimates size less than right, we
should `BuildLeft`, otherwise `BuildRight`
We have the first implemented, but we probably need second also. And should
we add an option to disable the size estimates based strategy?
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