Architecture Tour

The canonical architecture document lives at the repository root: open the full architecture reference. This chapter provides the site reading route without duplicating that source.

validated mutation -> WAL -> mutable segment
                                  |
                                flush
                                  v
query -> filter planner -> immutable segments
                                  |
                        version resolution
                                  v
                            global Top-K

Database owns collection directories and lifetimes. Collection is the only component allowed to order updates or publish a segment set. An upsert/delete batch is validated as a unit, written to the WAL, then applied with the WAL sequence as its version.

Search captures reference-counted immutable handles and a mutable snapshot, chooses a strategy per segment, discards stale versions, and merges candidates into one deterministic global Top-K. Optimization builds a replacement outside the update lock, publishes one new manifest, and deletes obsolete segments only after old readers release them.

Read next:

1. Qdrant mapping for subsystem correspondence.
2. Storage format for WAL, segment, manifest, and snapshot files.
3. Behavior matrix for tests that prove each contract.