org.apache.flink.runtime.state

Interface SnapshotStrategy<S extends StateObject>

Type Parameters:

S - type of the returned state object that represents the result of the snapshot operation.

All Known Subinterfaces:

OperatorStateBackend

All Known Implementing Classes:

AbstractKeyedStateBackend, AbstractSnapshotStrategy, DefaultOperatorStateBackend, HeapKeyedStateBackend, RocksDBKeyedStateBackend, RocksDBSnapshotStrategyBase, RocksFullSnapshotStrategy, RocksIncrementalSnapshotStrategy

@Internal
public interface SnapshotStrategy<S extends StateObject>

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.

Method Summary

Modifier and Type	Method and Description
RunnableFuture<S>	snapshot(long checkpointId, long timestamp, CheckpointStreamFactory streamFactory, CheckpointOptions checkpointOptions) Operation that writes a snapshot into a stream that is provided by the given CheckpointStreamFactory and returns a @RunnableFuture that gives a state handle to the snapshot.

Method Detail

snapshot

@Nonnull
RunnableFuture<S> snapshot(long checkpointId,
                                    long timestamp,
                                    @Nonnull
                                    CheckpointStreamFactory streamFactory,
                                    @Nonnull
                                    CheckpointOptions checkpointOptions)
                             throws Exception

Operation that writes a snapshot into a stream that is provided by the given CheckpointStreamFactory and returns a @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.

Parameters:

checkpointId - The ID of the checkpoint.

timestamp - The timestamp of the checkpoint.

streamFactory - The factory that we can use for writing our state to streams.

checkpointOptions - Options for how to perform this checkpoint.

Returns:

A runnable future that will yield a StateObject.

Throws:

Exception