[DISCUSS] Row-delta commits and multi-table transactions in iceberg-rust ? patterns from a CDC producer

[steveis]

Hi all,



I'm building an open-source Postgres→Iceberg CDC pipeline on iceberg-rust,
and two capabilities came up that felt broadly useful, so I've opened them
as draft PRs to discuss:



1.      RowDeltaAction (apache/iceberg-rust#2785
<https://github.com/apache/iceberg-rust/pull/2785> ) - the commit-side
equivalent of Java's Table.newRowDelta(): data files + delete files
(equality/position) in one overwrite snapshot. The crate already reads
delete files; this adds the missing write/commit side. It relates to #2218
(it's the commit-side complement of a DeltaWriter) and #2186. Includes an
end-to-end merge-on-read round-trip test.


2.      Multi-table transaction commits (apache/iceberg-rust#2786
<https://github.com/apache/iceberg-rust/pull/2786> , issue #2784) -
Transaction::prepare_commit() plus RestCatalog::commit_transaction(Vec)
driving the REST spec's /v1/{prefix}/transactions/commit. Our use case:
committing per-cadence row deltas to many tables plus a changelog table
atomically, validated against Lakekeeper.



Both are drafts and I'm happy to adapt the APIs to wherever the
merge-on-read work in #2186 is heading. Feedback very welcome.



Thanks,

Steve