ksqlDB

SQL streaming engine over Kafka Streams with persistent queries and materialized tables.

Provider: default
Kind: Stream processor
Category: Messaging
Official docs: https://docs.confluent.io/platform/current/ksqldb/reference/server-configuration.html

Properties · 5 set by this component

property	type	values	required	kind default	this component
autoOffsetReset · component property	enum	earliest \| latest	no	latest	inherited
checkpointIntervalSeconds	integer	—	no	—	▸ 2
deploymentMode · component property	enum	interactive \| headless	no	interactive	inherited
exactlyOnce	boolean	—	no	false	▸ false
instances	integer	—	no	—	inherited
lateDataPolicy	enum	drop \| shift \| sideline	no	—	inherited
managed	boolean	—	no	false	▸ false
stateBackend	enum	memory \| rocksdb \| external	no	memory	▸ rocksdb
streamThreads · component property	integer	—	no	4	inherited
watermarkSeconds	integer	—	no	—	inherited
windowing	enum	none \| event-time \| processing-time	no	none	▸ event-time

Rules that apply · 1

Every rule whose selector covers this component's kind or its category. Whether a rule fires depends on the design: its properties, its edges and its groups.

Event-time windows without watermarkwarning

windowed-aggregation-without-watermark

Event-time windows need a watermark to know when a window is complete. Without one the processor either waits forever or closes windows early and silently drops late events.

— all of these hold:
— the node's `windowing` is "event-time"
— the node's `watermarkSeconds` has no value

Use it in a design

nodes:
  - { id: "ksqldb", component: "ksqldb" }

Other Stream processor products · 33

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Source

1# yaml-language-server: $schema=../../schema/component.schema.json
2# ksqlDB: SQL streaming engine over Kafka Streams. "The processing semantics to use for persistent
3# queries. The default is at_least_once", the commit interval defaults to 2000 ms, auto.offset.reset
4# defaults to latest and Confluent Platform runs 4 stream threads
5# ("Confluent Platform, ksqlDB Server configuration parameters"). State stores are RocksDB backed.
6schemaVersion: "1"
7type: "component"
8id: "ksqldb"
9kind: "stream-processor"
10provider: "default"
11docs: "https://docs.confluent.io/platform/current/ksqldb/reference/server-configuration.html"
12defaults:
13  managed: false
14  windowing: "event-time"
15  checkpointIntervalSeconds: 2
16  exactlyOnce: false
17  stateBackend: "rocksdb"
18properties:
19  autoOffsetReset:
20    type: "enum"
21    values: ["earliest", "latest"]
22    default: "latest"
23  streamThreads:
24    type: "integer"
25    default: 4
26  deploymentMode:
27    type: "enum"
28    values: ["interactive", "headless"]
29    default: "interactive"

The same page as markdown, for an agent: /catalogue/components/ksqldb.md