JollyPixel

Appearance

Event store glossary ​

This glossary defines the vocabulary for recording and ordering asset events. Asset identity and classification come from the asset glossary. Rebuilding asset state and projecting it to storage belong to the asset-server glossary.

Terms ​

Event ​

An immutable record accepted into an asset's history. An event names what occurred, carries its domain data, identifies its actor, and records when the store accepted it.

Actor ​

The origin attributed to an event. A user actor carries a user identity. A system actor names the process or service that produced the event.

Event Stream ​

The ordered history of one asset. Events with the same asset ID form one stream.

Append ​

The act of recording a new event at the end of an asset's stream and the overall log. Appending extends history without revising earlier events.

Event ID ​

An event's position in the overall log across all asset streams. Event IDs express the order in which the store accepted events.

Event Version ​

An event's position in one asset stream. Versions increase independently for each asset and remain stable after compaction.

Event Log ​

The ordered collection of recorded events across all asset streams. The log grows through append operations and may shrink through compaction.

Event Store ​

The boundary through which an application records and reads event history. It owns the event log while leaving event meaning to its consumers.

Checkpoint ​

An event from which a consumer can rebuild an asset without reading earlier events. The consumer decides which event types qualify because it owns the fold.

Compaction ​

The irreversible removal of events that precede the newest checkpoint in each asset stream. The checkpoint, every later event, and every tagged event remain available.

Tag ​

A name attached to one event of an asset stream, unique within that asset. The tagged event survives compaction until its last tag is deleted.

Naming boundaries ​

  • Use event ID for position in the overall log and event version for position in one asset stream.
  • Use checkpoint for the event that makes earlier history unnecessary and compaction for removing that history.