rdblue commented on pull request #1919: URL: https://github.com/apache/iceberg/pull/1919#issuecomment-745710832
> The only open question I have is what about type promotion of partition fields. Partitions fields store the type output by the partition transform. In a lot of cases, that won't change. For example, bucket always produces ints no matter what the input type. Some transforms, like identity, will produce values of the input type. The only way to change the output type for those transforms is to change the input type through column promotion. When an identity partition column is promoted from int to long or float to double, the partition column is promoted automatically as well and the existing values are promoted on read. In case you're wondering, we were also careful to make sure type promotion doesn't change the result of any partition functions. If the partition transform doesn't produce the same value when it is promoted after transformation, then promotion must be done before the transformation: `bucket(int_col, width)` is actually `bucket((long) int_col, width)`. ---------------------------------------------------------------- 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: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: issues-unsubscr...@iceberg.apache.org For additional commands, e-mail: issues-h...@iceberg.apache.org
