Event store

Append-only replicated event log that is the system of record.

Category: Messaging
Properties: 6
Components: 5
Rules: 1

Properties · 6 defined by this kind

A node of this kind resolves each property from its own props, then the component's defaults, then the default below.

property	type	values	required	default
journaled	boolean	—	no	true
managed	boolean	—	no	false
replication	enum	none \| raft \| primary-replica	no	none
role	enum	journal \| sequencer	no	journal
snapshotIntervalEvents	integer	—	no	—
storage	enum	mmap \| rocksdb \| database	no	database

Rules for this kind · 1

Stateful engine pinned to a single zoneerror

stateful-engine-pinned-to-single-zone

A matching engine, coordination service or event store living in exactly one availability zone, with no failover and no replication, is lost with that zone. Everything that depends on it stops with it.

— all of these hold:
— the node sits inside exactly 1 availability-zone group
— any of these hold:
— the node's `failover` is "none"
— the node's `replicated` is false
— the node's `replication` is "none"

Components · 5

vendor-neutral

Generic event storeevent-storegenericthe kind itself

default

Axon Serveraxon-server4 defaults Apache BookKeeperbookkeeper3 defaults EventStoreDBeventstoredb5 defaults Raft event lograft-event-log4 defaults

Source

1# yaml-language-server: $schema=../schema/kind.schema.json
2# Append-only, replicated event log that is the system of record (event sourcing, exchange journals, sequencers).
3# Differs from stream: state is derived from it and it is snapshotted; role sequencer marks the single writer that orders events.
4schemaVersion: "1"
5type: "kind"
6id: "event-store"
7category: "messaging"
8properties:
9  replication:
10    type: "enum"
11    values: ["none", "raft", "primary-replica"]
12    default: "none"
13  journaled:
14    type: "boolean"
15    default: true
16  snapshotIntervalEvents:
17    type: "integer"
18  storage:
19    type: "enum"
20    values: ["mmap", "rocksdb", "database"]
21    default: "database"
22  role:
23    type: "enum"
24    values: ["journal", "sequencer"]
25    default: "journal"
26  managed:
27    type: "boolean"
28    default: false

The same page as markdown, for an agent: /catalogue/kinds/event-store.md