HyukjinKwon commented on a change in pull request #28032:
URL: https://github.com/apache/spark/pull/28032#discussion_r646222780
##########
File path:
sql/catalyst/src/main/scala/org/apache/spark/sql/internal/SQLConf.scala
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@@ -2435,6 +2435,15 @@ object SQLConf {
.booleanConf
.createWithDefault(true)
+ val REPARTITION_BEFORE_INSERT =
+ buildConf("spark.sql.execution.repartitionBeforeInsert")
+ .internal()
+ .doc("When perform a insert into partitioned table. Turn on this config
to " +
+ "insert a repartition by dynamic partition columns to ease pressure on
the NameNode " +
Review comment:
Do you mind how it reduces the pressure on the NMs? I don't think people
can understand what happens by reading docs.
I would describe it concisely and easy to understand (e.g., p. 44 - 48
https://www.slideshare.net/TejasPatil1/hive-bucketing-in-apache-spark). It's
bucketing but we could resue it for partitioning for such as the number of
files and diagrams.
Probably we should describe pros and cons, and when it should be turned on.
Feel free to write something in
https://github.com/apache/spark/blob/master/docs/sql-performance-tuning.md too.
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