This documentation is for an unreleased version of Apache Paimon. We recommend you use the latest stable version.

Overview #

When Paimon sink receives two or more records with the same primary keys, it will merge them into one record to keep primary keys unique. By specifying the merge-engine table property, users can choose how records are merged together.

Always set table.exec.sink.upsert-materialize to NONE in Flink SQL TableConfig, sink upsert-materialize may result in strange behavior. When the input is out of order, we recommend that you use Sequence Field to correct disorder.

Deduplicate #

The deduplicate merge engine is the default merge engine. Paimon will only keep the latest record and throw away other records with the same primary keys.

Specifically, if the latest record is a DELETE record, all records with the same primary keys will be deleted. You can config ignore-delete to ignore it.