viirya commented on issue #26461: [SPARK-29831][SQL] Scan Hive partitioned table should not dramatically increase data parallelism URL: https://github.com/apache/spark/pull/26461#issuecomment-552581081 @dongjoon-hyun Thanks for review. As I mentioned in the description, although end-users can add coalesce by Dataset or SQL APIs, the reason to add this config is based on: 1. end-users might not understand details and get confused by big partition number. end-users might not know why/when/where to add coalesce. 2. end-users need to add coalesce to each time Hive table scan. It is annoying. From the perspective of of cluster operator, it is much easier to config instead of asking each end-users to know the details and add coalesce. The current behavior of Hive scan is not friendly for end-users and cluster operator. We have better behavior on datasource table scan node, but in some user cases we still need read Hive table.
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