[flink] Single-row lookup pushdown returns empty for lake-only (expired) partitions

[fresh-borzoni]

Search before asking

• I searched in the issues and found nothing similar.

Fluss version

main (development)

Please describe the bug 🐞

A full primary-key point query on a lake-enabled partitioned table (FULL) is rewritten to a kv single-row lookup. It reads only Fluss kv, so for a partition expired from Fluss but still in the lake it returns empty, yet the union scan(or a partial-key filter) returns the row.

The COUNT(*) pushdown already guards this via isDataLakeEnabled and the single-row lookup doesn't.

Solution

Gate the lookup on partition liveness, else fall back to the union scan.

Are you willing to submit a PR?

• I'm willing to submit a PR!