Introduction

Cobble Flink integrates Cobble with Apache Flink®, so you can use Cobble as a Flink state backend, SQL source, and SQL sink.

Features

Cobble Flink currently provides:

• a state backend for stateful Flink jobs
• a SQL source for reading Cobble data in Flink SQL
• a SQL sink for writing Flink SQL results into Cobble
• a bundled runtime jar for Flink cluster deployment
• a web monitor for inspecting checkpoint and sink snapshots

Cobble Flink supports Flink 1.17 and later. See Getting Started for the version matrix.

Why Cobble Flink

Flink state is essential to a stateful job, but it is often visible only to the running job and restore tooling. Cobble Flink makes persisted state easier to understand and reuse:

• See what Flink stored. The web monitor can browse checkpoints and sink snapshots by operator and state, then decode keys and values into semantic fields when schema information is available.
• Consume state as data. The SQL source can scan or look up Cobble sink tables and supported keyed state directly, including structured semantic columns. Persisted state is no longer useful only for job recovery.
• Use one storage layer across workflows. State backend, source, sink, metrics, and remote storage support work together, making it easier to debug a job, validate its state, and build new Flink pipelines from existing data.

This brings a different experience to stateful Flink: managed state remains part of the runtime while becoming observable and consumable. The same applies to tables written by the Cobble sink: users can inspect their snapshots and read the data back through the Cobble source.

Showcase

The diagram shows how Cobble connects Flink storage and consumption paths:

• Flink jobs can persist managed state or sink tables in Cobble while processing streams such as Kafka topics.
• Other Flink jobs can scan or continuously read the persisted data, or use it for exact-key lookup joins.
• The web monitor reads the same snapshots so users can inspect keys, values, and semantic columns without modifying the running job.

Documentation Structure

Chapter	Description
Getting Started	Install Cobble Flink and choose a version
State Backend	Store Flink managed state in Cobble
Source	Read Cobble data from Flink SQL
Sink	Write Flink SQL results to Cobble
Web Monitor	Inspect checkpoints and tables
Metrics	Monitor state backend and connector activity