viirya commented on a change in pull request #26461: [SPARK-29831][SQL] Scan
Hive partitioned table should not dramatically increase data parallelism
URL: https://github.com/apache/spark/pull/26461#discussion_r344565178
##########
File path: sql/hive/src/main/scala/org/apache/spark/sql/hive/HiveUtils.scala
##########
@@ -155,6 +155,16 @@ private[spark] object HiveUtils extends Logging {
.booleanConf
.createWithDefault(true)
+ val HIVE_TABLE_SCAN_MAX_PARALLELISM =
buildConf("spark.sql.hive.tableScan.maxParallelism")
Review comment:
When reading a Hive partitioned table, users could get an unreasonable
number of partitions like dozens of thousands.
Hive Scan node returns a UnionRDD of Hive table partitions. Each Hive table
partition is read as a HadoopRDD. For each Hive table partition, the
parallelism depends on data size. But final UnionRDD sums up all number of
parallelism of all Hive table partitions.
----------------------------------------------------------------
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]
