[GitHub] [pinot] richardstartin opened a new issue, #8837: `order by DESC limit N` queries are not optimised at segment level

[GitBox]

richardstartin opened a new issue, #8837:
URL: https://github.com/apache/pinot/issues/8837

   A query like 
   
   ```sql
   SELECT *
   FROM table
   WHERE filter
   ORDER BY sorted_col DESC
   LIMIT 10;
   ```
   
   is not optimised and hits the generic 
`SelectionOrderByOperator.computePartiallyOrdered()` which inserts up to 10k 
elements into a priority queue to discard all but the last 10. For ascending 
order, the query below is roughly 3-4x faster per segment.
   
   ```sql
   SELECT *
   FROM table
   WHERE filter
   ORDER BY sorted_col ASC
   LIMIT 10;
   ```


-- 
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: commits-unsubscr...@pinot.apache.org.apache.org

For queries about this service, please contact Infrastructure at:
us...@infra.apache.org


---------------------------------------------------------------------
To unsubscribe, e-mail: commits-unsubscr...@pinot.apache.org
For additional commands, e-mail: commits-h...@pinot.apache.org