liancheng edited a comment on issue #25382: [SPARK-28651][SS]Force streaming 
file source to be nullable
URL: https://github.com/apache/spark/pull/25382#issuecomment-519645724
 
 
   Unfortunately, I didn't add a comprehensive PR description or comments in 
the original PR to explain why we wanted a nullable schema (I guess we were 
rushing the 1.4 release back then)...
   
   From what I could recall, possible motivations could be due to Hive 
compatibility and Parquet interoperability. Hive metastore doesn't respect 
nullability and always have nullable columns. Parquet interoperability was in 
trouble in 1.4 due to ambiguity in the parquet-format spec and different 
systems were using different schemas when writing nested columns, and forcing 
the schema nullable could help in resolving part of the cases (esp. for Hive). 
But Spark Parquet interoperability is no longer an issue since 1.6.

----------------------------------------------------------------
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]

Reply via email to