title: Spark - High task deserialization time
body: <p>I am running a job using Spark Sql with some complex queries (group by 7 fields, partition by 5 fields and rank etc. ). When I am running the job on a large dataset (1TB in parquet), task deserialization time is very high for one of the stage. But the logs just says that its reading data from parquet files (from S3). Can anyone please help me understand why this is happening. I can tell that jar size is not the issue since I don't see this in other stages. </p>
  
  <p>If I have to use Kyro serialization, how will I use it with Dataset ? (I am not using any custom objects)</p>
  
  <p><a href="https://i.stack.imgur.com/BEKbO.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/BEKbO.png" alt="enter image description here"></a></p>