[SPARK-11914] [SQL] Support coalesce and repartition in Dataset APIs #9899
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Test build #46507 has finished for PR 9899 at commit
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Thanks - I'm merging this in. |
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This PR is to provide two common `coalesce` and `repartition` in Dataset APIs. After reading the comments of SPARK-9999, I am unclear about the plan for supporting re-partitioning in Dataset APIs. Currently, both RDD APIs and Dataframe APIs provide users such a flexibility to control the number of partitions. In most traditional RDBMS, they expose the number of partitions, the partitioning columns, the table partitioning methods to DBAs for performance tuning and storage planning. Normally, these parameters could largely affect the query performance. Since the actual performance depends on the workload types, I think it is almost impossible to automate the discovery of the best partitioning strategy for all the scenarios. I am wondering if Dataset APIs are planning to hide these APIs from users? Feel free to reject my PR if it does not match the plan. Thank you for your answers. marmbrus rxin cloud-fan Author: gatorsmile <gatorsmile@gmail.com> Closes #9899 from gatorsmile/coalesce. (cherry picked from commit 238ae51) Signed-off-by: Reynold Xin <rxin@databricks.com>
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This PR is to provide two common
coalesceandrepartitionin Dataset APIs.After reading the comments of SPARK-9999, I am unclear about the plan for supporting re-partitioning in Dataset APIs. Currently, both RDD APIs and Dataframe APIs provide users such a flexibility to control the number of partitions.
In most traditional RDBMS, they expose the number of partitions, the partitioning columns, the table partitioning methods to DBAs for performance tuning and storage planning. Normally, these parameters could largely affect the query performance. Since the actual performance depends on the workload types, I think it is almost impossible to automate the discovery of the best partitioning strategy for all the scenarios.
I am wondering if Dataset APIs are planning to hide these APIs from users? Feel free to reject my PR if it does not match the plan.
Thank you for your answers. @marmbrus @rxin @cloud-fan