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Flink SQL Advanced Topics

State bootstraping

The Flink stateful function State Bootstrapping helps to load data in Flink snapshot as a way to bootstrap Flink stateful statement.

Bootstrap Queries

In Confluent Cloud load data from kafka topic or tableflow table, to load historical data then automatically switch to streaming data from Kafka. It leverages Flink’s HybridSource which is a capacity to read data from different bounded sources to a unique input stream.

Some constraints

  • Reading historical data from Iceberg table do not guaranty the record order (using kafka offset for example). This could affect correctness of query operator like LAST_VALUE, LAG, MATCH_RECOGNIZE. Event-Time dependent operators may experience latent results.
  • Reading historical data from Kafka, will keep offset ordering per partition.