Lib.rs

Columnar storage engine: the immutable, on-disk representation of materialized columns plus the read-time machinery (compute kernels, predicates, scans, selection vectors, snapshots) the engine uses to query them. This crate owns the bucket layout, the per-column compression and encoding schemes, and the registry that tracks which columns are present and at what version.

Read paths come in here, get a column reader, and stream values through compute kernels that operate directly on the encoded bytes where possible - decoding only when a kernel cannot run on the encoded form. The snapshot type is what the subscription tier hands out to consumers so they can iterate over a stable view of the column without racing against ongoing writes.

Invariant: a column's encoded bytes plus its stats and bitmap are produced together and never updated piecewise. Tearing those apart - rewriting just the values, just the bitmap, or just the stats - means readers can observe a column whose statistics no longer describe its contents, which silently corrupts every kernel that reads stats to skip work.