org.apache.flink.runtime.state.SnapshotStrategy Maven / Gradle / Ivy
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* to you under the Apache License, Version 2.0 (the
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*
* http://www.apache.org/licenses/LICENSE-2.0
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package org.apache.flink.runtime.state;
import org.apache.flink.runtime.checkpoint.CheckpointOptions;
import java.util.concurrent.RunnableFuture;
/**
* Interface for different snapshot approaches in state backends. Implementing classes should ideally be stateless or at
* least threadsafe, i.e. this is a functional interface and is can be called in parallel by multiple checkpoints.
*
* @param type of the returned state object that represents the result of the snapshot operation.
*/
@FunctionalInterface
public interface SnapshotStrategy {
/**
* Operation that writes a snapshot into a stream that is provided by the given {@link CheckpointStreamFactory} and
* returns a @{@link RunnableFuture} that gives a state handle to the snapshot. It is up to the implementation if
* the operation is performed synchronous or asynchronous. In the later case, the returned Runnable must be executed
* first before obtaining the handle.
*
* @param checkpointId The ID of the checkpoint.
* @param timestamp The timestamp of the checkpoint.
* @param streamFactory The factory that we can use for writing our state to streams.
* @param checkpointOptions Options for how to perform this checkpoint.
* @return A runnable future that will yield a {@link StateObject}.
*/
RunnableFuture performSnapshot(
long checkpointId,
long timestamp,
CheckpointStreamFactory streamFactory,
CheckpointOptions checkpointOptions) throws Exception;
}