amogh-jahagirdar commented on PR #5364: URL: https://github.com/apache/iceberg/pull/5364#issuecomment-1227902420
Discussed offline with @rdblue , I got an understanding of how history entries are different than the snapshot order, posting the information here so folks referring to the PR have context: "History is the state of main at any given time. That can be changed, much like master in git can be changed. Ancestors can't be changed." The current main can change when rollback is performed. The snapshot which gets resolved for a given time T should remain constant regardless of what is the current main ancestor lineage. History entries capture all the changes on the main table state and are what enable this ability to time travel to a snapshot which are outside the current table ancestors. It also doesn't make sense to treat main as a separate case, and have a different semantic for non-main branches when it comes to time travel. Maybe we could maintain separate history metadata for branches, but most likely it would need to be opt-in by users and would need to not add too much metadata to manage. So for now, it makes sense just to do time travel to a branch tip or time travel to a given tag. -- 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]
