Complete redb schema with bidirectional relation indexing:
- RELS multimap: uuid → packed(other_uuid, strength, rel_type, is_outgoing)
- Each edge stored twice (once per endpoint) with direction bit
- pack_rel/unpack_rel for 22-byte packed format
Wired up:
- replay_relations indexes all relations on load
- add_relation indexes new relations
- for_each_relation reads from index (graph building)
- add_link uses index for existence check
- set_link_strength finds/updates edges via index
- cap_degree uses index for degree counting and pruning
- rename_node finds edges by uuid
Vec<Relation> still maintained for remaining uses (normalize_strengths,
graph_health diagnostics). To be removed in follow-up.
Co-Authored-By: Kent Overstreet <kent.overstreet@linux.dev>
Restructure store module with clearer file names:
- persist.rs → capnp.rs (capnp log IO)
- db.rs → index.rs (redb index operations)
redb now stores key → offset mapping, not serialized nodes.
Mutations record the offset after appending to capnp log.
rebuild_index scans capnp log to reconstruct the index.
The HashMap still exists for now; next step is to use the
index for lookups and remove it.
Co-Authored-By: Proof of Concept <poc@bcachefs.org>
