| Core |
Feed |
A named logical collection of records. Each feed contains streams and a commit history. Subscriptions and a writer lease are scoped to the feed. |
| Core |
Stream |
A logical boundary on a feed for one ingest run. Records append to the stream while it is open. The producer decides what belongs in it and when to seal. After seal, the stream is immutable and represented by a commit in the feed history. |
| Core |
Record |
The atomic stored item. A record contains a stream-local sequence number, timestamp, opaque fingerprint, payload, and optional key, version, and tombstone marker. |
| Core |
Commit |
A published point in a feed's history. A commit records its feed sequence, source stream, parent commit, record count, timestamps, message, and storage artifacts. |
| Producer |
Batch |
A group of records submitted as one append operation. A batch can include optimistic sequence matching and fencing information. |
| Consumer |
Cursor |
A position in a feed's commit history. Reads begin after the commit identified by the cursor. Feed cursors remain the continuous-consumption model. Sealed and unsealed streams can also be read directly. |
| Consumer |
Subscription |
A named, persisted cursor for a feed. Polling reads from the saved position to the current head. Advancing the subscription updates that position. |
| Storage |
Write-ahead log |
Durable storage for appended records before sealing completes. Append acknowledgements are returned after the batch reaches a WAL segment. |
| Storage |
Pack |
Stores record payload bytes. Identical payloads can reuse an existing pack location. |
| Storage |
Manifest |
Stores ordered record metadata and the locations of payloads in packs. |
| Storage |
Key index |
Stores keyed-record winners and occurrences for latest-value reads and point lookups. |
| Storage |
Commit record |
Publishes references to the packs, manifests, and key indexes that represent the sealed stream. |
| Coordination |
Writer lease |
Grants one node write ownership of a feed for a limited period. |
| Coordination |
Writer epoch |
A monotonically increasing generation assigned whenever feed ownership is acquired. |
| Coordination |
Fencing token |
Rejects appends from writers that no longer own the active stream. |