Generation of Snapshot Summaries

[Fokko]

With each snapshot comes a summary map, optional in V1, required in V2 and later:

The summary contains information such as what kind of files the snapshot contains (data/delete), and what the changes are in rows and bytes. The best way to replicate this metrics collection is by looking at the Java code: https://github.com/apache/iceberg/blob/main/core/src/main/java/org/apache/iceberg/SnapshotSummary.java

This class works closely alongside the SnapshotProducer and tracks what happens with the snapshot.

[barronw]

Can I pick this up?

[c-thiel]

@barronw gladly! Assigned the issue to you :)

[barronw]

@c-thiel Feel free to re-assign this to someone else (maybe @jonathanc-n). I won't be able to complete this soon, so I pushed what I have to my fork for reference (link).