State & Fault Tolerance

This documentation is for an out-of-date version of Apache Flink. We recommend you use the latest stable version.

In this section you will learn about the APIs that Flink provides for writing stateful programs. Please take a look at Stateful Stream Processing to learn about the concepts behind stateful stream processing.

Where to go next?

Working with State: Shows how to use state in a Flink application and explains the different kinds of state.
The Broadcast State Pattern: Explains how to connect a broadcast stream with a non-broadcast stream and use state to exchange information between them.
Checkpointing: Describes how to enable and configure checkpointing for fault tolerance.
Queryable State: Explains how to access state from outside of Flink during runtime.
State Schema Evolution: Shows how schema of state types can be evolved.
Custom Serialization for Managed State: Discusses how to implement custom serializers, especially for schema evolution.