Module partitioning 

Deterministic TopicIdPartition → metadata-topic-partition mapping.

Every metadata event for one user partition must land in the same __remote_log_metadata partition, so its lifecycle ordering survives the round trip through Kafka. The hash inputs are topic_id and partition, which match the identity of TopicIdPartition. A topic rename therefore does not move the bucket.

Functions

metadata_partition_for

Pick the metadata-topic partition for tp, given the partition_count of __remote_log_metadata.

metadata_partitions_for

Deduped, sorted set of __remote_log_metadata partitions that carry metadata for the given user-topic-partitions, for the metadata topic’s partition_count.