Module retention 

Cell-level retention merger for bitemporal tile compaction.

merge_for_retention replaces the tile-granularity partition_by_retention for compaction paths that must honour the sparse tile model: because tile-versions are SPARSE (each version only stores the cells that were written at that system_from_ms), the retention ceiling must be computed per cell coordinate, not per tile.

Structs

DecodedRow

Decoded row from a SparseTile.

RetentionMergeResult

Result of merge_for_retention.

Functions

decode_sparse_rows

Iterate every row in a SparseTile, decoding coords and payload.

encode_coord_key

Encode a coordinate vector into a stable byte key for HashMap / HashSet use.

merge_for_retention

Merge tile-versions for one hilbert_prefix according to the retention policy, operating at cell granularity.