clear() removed entities, indexes, system and _cas but left three top-level
trees on disk: _blobs (raw HNSW/LSM segment bytes and the native dkann index),
_id_mapper (the native shared mmap id-mapper), and _column_index (column-store
manifests). A cleared brain therefore re-read stale native state.
Worse, the column store splits its state across two of those trees — manifests
under _column_index/ and their segment bytes under _blobs/_column_index/ — so
removing one without the other stranded a manifest listing segments that no
longer exist, which the hardened segment-load path now (correctly) refuses with
ColumnSegmentLoadError. The three trees now fall together as a set, exactly as
_cas already does. locks/ is deliberately preserved: it is live coordination
state, not data.
David Snelling
d8301f8d08