srowen commented on pull request #28488:
URL: https://github.com/apache/spark/pull/28488#issuecomment-626366492


   I recall this was discussed at 
https://issues.apache.org/jira/browse/SPARK-27025?focusedCommentId=16782789&page=com.atlassian.jira.plugin.system.issuetabpanels%3Acomment-tabpanel#comment-16782789
 which might be worth a read. I think the TL;DR from me was that fetching 1 
additional iterator could be fine.
   
   I'm a little worried about correctness issues, thread-safety, in the 
presence of failures, etc. Like where do you get the error when if the prefetch 
fails? but I have not thought it through.


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



---------------------------------------------------------------------
To unsubscribe, e-mail: [email protected]
For additional commands, e-mail: [email protected]

Reply via email to