cloud-fan commented on a change in pull request #27669: [SPARK-30918][SQL]
improve the splitting of skewed partitions
URL: https://github.com/apache/spark/pull/27669#discussion_r383738095
##########
File path:
sql/core/src/main/scala/org/apache/spark/sql/execution/adaptive/OptimizeSkewedJoin.scala
##########
@@ -61,6 +85,19 @@ case class OptimizeSkewedJoin(conf: SQLConf) extends
Rule[SparkPlan] {
}
}
+ /**
+ * The goal of skew join optimization is to make the data distribution more
even. The target size
+ * to split skewed partitions is the average size of non-skewed partition,
or the
+ * target post-shuffle partition size if avg size is smaller than it.
+ */
+ private def targetSize(stats: MapOutputStatistics, medianSize: Long): Long =
{
+ val targetPostShuffleSize =
conf.getConf(SQLConf.SHUFFLE_TARGET_POSTSHUFFLE_INPUT_SIZE)
Review comment:
@JkSelf do you have any real-world use cases for it? I noticed it as well
but have the same feeling with @maryannxue : why would users set a different
value?
----------------------------------------------------------------
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.
For queries about this service, please contact Infrastructure at:
[email protected]
With regards,
Apache Git Services
---------------------------------------------------------------------
To unsubscribe, e-mail: [email protected]
For additional commands, e-mail: [email protected]
