westonpace commented on issue #34313:
URL: https://github.com/apache/arrow/issues/34313#issuecomment-1443737729

   The various formats aren't typically used directly, but through the scanner 
here: 
https://github.com/apache/arrow/blob/apache-arrow-11.0.0/cpp/src/arrow/dataset/scanner.cc#L728
   
   So the logic is basically:
   
   If we can know the row count without scanning the file then return it.  
Else, if we can't know the exact count, return nullopt and let the scanner 
figure out the exact count with in-memory filtering.


-- 
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.

To unsubscribe, e-mail: [email protected]

For queries about this service, please contact Infrastructure at:
[email protected]

Reply via email to