org.apache.flink.table.connector.ParallelismProvider Maven / Gradle / Ivy
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*
* http://www.apache.org/licenses/LICENSE-2.0
*
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package org.apache.flink.table.connector;
import org.apache.flink.annotation.PublicEvolving;
import org.apache.flink.table.connector.sink.DynamicTableSink.SinkRuntimeProvider;
import java.util.Optional;
/**
* Parallelism provider for other connector providers. It allows to express a custom parallelism for
* the connector runtime implementation. Otherwise the parallelism is determined by the planner.
*
* Note: Currently, this interface only works with {@link SinkRuntimeProvider}.
*/
@PublicEvolving
public interface ParallelismProvider {
/**
* Returns the parallelism for this instance.
*
*
The parallelism denotes how many parallel instances of a source or sink will be spawned
* during the execution.
*
*
Enforcing a different parallelism for sinks might mess up the changelog if the input is
* not {@link ChangelogMode#insertOnly()}. Therefore, a primary key is required by which the
* input will be shuffled before records enter the {@link SinkRuntimeProvider} implementation.
*
* @return empty if the connector does not provide a custom parallelism, then the planner will
* decide the number of parallel instances by itself.
*/
default Optional getParallelism() {
return Optional.empty();
}
}