adriangb commented on PR #25576: URL: https://github.com/apache/datafusion/pull/25576#issuecomment-5766788796
> No, from my understanding it doesn't need to be exact. Even if it were, it wouldn't be any more useful than an estimation, for the reasons you mentioned. A parquet file with two row groups with an NDV of 100 and 101 respectively can have between 101 and 201 unique values. In that case, it's probably never safe or even helpful to read it in as `Exact`, should we always read it in as `Inexact`? -- 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] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
