java.lang.Object
- org.apache.flink.state.api.SavepointReader

@PublicEvolving
public class SavepointReader
extends Object

The entry point for reading state from a Flink savepoint.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`static SavepointReader`	`read(org.apache.flink.streaming.api.environment.StreamExecutionEnvironment env, String path)`	Loads an existing savepoint.
`static SavepointReader`	`read(org.apache.flink.streaming.api.environment.StreamExecutionEnvironment env, String path, org.apache.flink.runtime.state.StateBackend stateBackend)`	Loads an existing savepoint.
`<K,V> org.apache.flink.streaming.api.datastream.DataStream<org.apache.flink.api.java.tuple.Tuple2<K,V>>`	`readBroadcastState(OperatorIdentifier identifier, String name, org.apache.flink.api.common.typeinfo.TypeInformation<K> keyTypeInfo, org.apache.flink.api.common.typeinfo.TypeInformation<V> valueTypeInfo)`	Read operator `BroadcastState` from a `Savepoint`.
`<K,V> org.apache.flink.streaming.api.datastream.DataStream<org.apache.flink.api.java.tuple.Tuple2<K,V>>`	`readBroadcastState(OperatorIdentifier identifier, String name, org.apache.flink.api.common.typeinfo.TypeInformation<K> keyTypeInfo, org.apache.flink.api.common.typeinfo.TypeInformation<V> valueTypeInfo, org.apache.flink.api.common.typeutils.TypeSerializer<K> keySerializer, org.apache.flink.api.common.typeutils.TypeSerializer<V> valueSerializer)`	Read operator `BroadcastState` from a `Savepoint` when a custom serializer was used; e.g., a different serializer than the one returned by `TypeInformation#createSerializer`.
`<K,OUT> org.apache.flink.streaming.api.datastream.DataStream<OUT>`	`readKeyedState(OperatorIdentifier identifier, KeyedStateReaderFunction<K,OUT> function)`	Read keyed state from an operator in a `Savepoint`.
`<K,OUT> org.apache.flink.streaming.api.datastream.DataStream<OUT>`	`readKeyedState(OperatorIdentifier identifier, KeyedStateReaderFunction<K,OUT> function, org.apache.flink.api.common.typeinfo.TypeInformation<K> keyTypeInfo, org.apache.flink.api.common.typeinfo.TypeInformation<OUT> outTypeInfo)`	Read keyed state from an operator in a `Savepoint`.
`<T> org.apache.flink.streaming.api.datastream.DataStream<T>`	`readListState(OperatorIdentifier identifier, String name, org.apache.flink.api.common.typeinfo.TypeInformation<T> typeInfo)`	Read operator `ListState` from a `Savepoint`.
`<T> org.apache.flink.streaming.api.datastream.DataStream<T>`	`readListState(OperatorIdentifier identifier, String name, org.apache.flink.api.common.typeinfo.TypeInformation<T> typeInfo, org.apache.flink.api.common.typeutils.TypeSerializer<T> serializer)`	Read operator `ListState` from a `Savepoint` when a custom serializer was used; e.g., a different serializer than the one returned by `TypeInformation#createSerializer`.
`<T> org.apache.flink.streaming.api.datastream.DataStream<T>`	`readUnionState(OperatorIdentifier identifier, String name, org.apache.flink.api.common.typeinfo.TypeInformation<T> typeInfo)`	Read operator `UnionState` from a `Savepoint`.
`<T> org.apache.flink.streaming.api.datastream.DataStream<T>`	`readUnionState(OperatorIdentifier identifier, String name, org.apache.flink.api.common.typeinfo.TypeInformation<T> typeInfo, org.apache.flink.api.common.typeutils.TypeSerializer<T> serializer)`	Read operator `UnionState` from a `Savepoint` when a custom serializer was used; e.g., a different serializer than the one returned by `TypeInformation#createSerializer`.
`<W extends org.apache.flink.streaming.api.windowing.windows.Window> WindowSavepointReader<W>`	`window(org.apache.flink.api.common.typeutils.TypeSerializer<W> windowSerializer)`	Read window state from an operator in a `Savepoint`.
`<W extends org.apache.flink.streaming.api.windowing.windows.Window> WindowSavepointReader<W>`	`window(org.apache.flink.streaming.api.windowing.assigners.WindowAssigner<?,W> assigner)`	Read window state from an operator in a `Savepoint`.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

read
```
public static SavepointReader read(org.apache.flink.streaming.api.environment.StreamExecutionEnvironment env,
                                   String path)
                            throws IOException
```
Loads an existing savepoint. Useful if you want to query the state of an existing application. The savepoint will be read using the state backend defined via the clusters configuration.

Parameters:

env - The execution environment used to transform the savepoint.

path - The path to an existing savepoint on disk.

Returns:

A SavepointReader.

Throws:

IOException

read

public static SavepointReader read(org.apache.flink.streaming.api.environment.StreamExecutionEnvironment env,
                                   String path,
                                   org.apache.flink.runtime.state.StateBackend stateBackend)
                            throws IOException

Loads an existing savepoint. Useful if you want to query the state of an existing application.

Parameters:: env - The execution environment used to transform the savepoint.; path - The path to an existing savepoint on disk.; stateBackend - The state backend of the savepoint.
Returns:: A SavepointReader.
Throws:: IOException

readListState

public <T> org.apache.flink.streaming.api.datastream.DataStream<T> readListState(OperatorIdentifier identifier,
                                                                                 String name,
                                                                                 org.apache.flink.api.common.typeinfo.TypeInformation<T> typeInfo)
                                                                          throws IOException

Read operator ListState from a Savepoint.

Type Parameters:: T - The type of the values that are in the list state.
Parameters:: identifier - The identifier of the operator.; name - The (unique) name for the state.; typeInfo - The type of the elements in the state.
Returns:: A DataStream representing the elements in state.
Throws:: IOException - If the savepoint path is invalid or the uid does not exist.

readListState

public <T> org.apache.flink.streaming.api.datastream.DataStream<T> readListState(OperatorIdentifier identifier,
                                                                                 String name,
                                                                                 org.apache.flink.api.common.typeinfo.TypeInformation<T> typeInfo,
                                                                                 org.apache.flink.api.common.typeutils.TypeSerializer<T> serializer)
                                                                          throws IOException

Read operator ListState from a Savepoint when a custom serializer was used; e.g., a different serializer than the one returned by


 TypeInformation#createSerializer

.

Type Parameters:: T - The type of the values that are in the list state.
Parameters:: identifier - The identifier of the operator.; name - The (unique) name for the state.; typeInfo - The type of the elements in the state.; serializer - The serializer used to write the elements into state.
Returns:: A DataStream representing the elements in state.
Throws:: IOException - If the savepoint path is invalid or the uid does not exist.

readUnionState

public <T> org.apache.flink.streaming.api.datastream.DataStream<T> readUnionState(OperatorIdentifier identifier,
                                                                                  String name,
                                                                                  org.apache.flink.api.common.typeinfo.TypeInformation<T> typeInfo)
                                                                           throws IOException

Read operator UnionState from a Savepoint.

Type Parameters:: T - The type of the values that are in the union state.
Parameters:: identifier - The identifier of the operator.; name - The (unique) name for the state.; typeInfo - The type of the elements in the state.
Returns:: A DataStream representing the elements in state.
Throws:: IOException - If the savepoint path is invalid or the uid does not exist.

readUnionState

public <T> org.apache.flink.streaming.api.datastream.DataStream<T> readUnionState(OperatorIdentifier identifier,
                                                                                  String name,
                                                                                  org.apache.flink.api.common.typeinfo.TypeInformation<T> typeInfo,
                                                                                  org.apache.flink.api.common.typeutils.TypeSerializer<T> serializer)
                                                                           throws IOException

Read operator UnionState from a Savepoint when a custom serializer was used; e.g., a different serializer than the one returned by


 TypeInformation#createSerializer

.

Type Parameters:: T - The type of the values that are in the union state.
Parameters:: identifier - The identifier of the operator.; name - The (unique) name for the state.; typeInfo - The type of the elements in the state.; serializer - The serializer used to write the elements into state.
Returns:: A DataStream representing the elements in state.
Throws:: IOException - If the savepoint path is invalid or the uid does not exist.

readBroadcastState

public <K,V> org.apache.flink.streaming.api.datastream.DataStream<org.apache.flink.api.java.tuple.Tuple2<K,V>> readBroadcastState(OperatorIdentifier identifier,
                                                                                                                                              String name,
                                                                                                                                              org.apache.flink.api.common.typeinfo.TypeInformation<K> keyTypeInfo,
                                                                                                                                              org.apache.flink.api.common.typeinfo.TypeInformation<V> valueTypeInfo)
                                                                                                                                       throws IOException

Read operator BroadcastState from a Savepoint.

Type Parameters:: K - The type of keys in state.; V - The type of values in state.
Parameters:: identifier - The identifier of the operator.; name - The (unique) name for the state.; keyTypeInfo - The type information for the keys in the state.; valueTypeInfo - The type information for the values in the state.
Returns:: A DataStream of key-value pairs from state.
Throws:: IOException - If the savepoint does not contain the specified uid.

readBroadcastState

public <K,V> org.apache.flink.streaming.api.datastream.DataStream<org.apache.flink.api.java.tuple.Tuple2<K,V>> readBroadcastState(OperatorIdentifier identifier,
                                                                                                                                              String name,
                                                                                                                                              org.apache.flink.api.common.typeinfo.TypeInformation<K> keyTypeInfo,
                                                                                                                                              org.apache.flink.api.common.typeinfo.TypeInformation<V> valueTypeInfo,
                                                                                                                                              org.apache.flink.api.common.typeutils.TypeSerializer<K> keySerializer,
                                                                                                                                              org.apache.flink.api.common.typeutils.TypeSerializer<V> valueSerializer)
                                                                                                                                       throws IOException

Read operator BroadcastState from a Savepoint when a custom serializer was used; e.g., a different serializer than the one returned by


 TypeInformation#createSerializer

.

Type Parameters:: K - The type of keys in state.; V - The type of values in state.
Parameters:: identifier - The identifier of the operator.; name - The (unique) name for the state.; keyTypeInfo - The type information for the keys in the state.; valueTypeInfo - The type information for the values in the state.; keySerializer - The type serializer used to write keys into the state.; valueSerializer - The type serializer used to write values into the state.
Returns:: A DataStream of key-value pairs from state.
Throws:: IOException - If the savepoint path is invalid or the uid does not exist.

readKeyedState

public <K,OUT> org.apache.flink.streaming.api.datastream.DataStream<OUT> readKeyedState(OperatorIdentifier identifier,
                                                                                              KeyedStateReaderFunction<K,OUT> function)
                                                                                       throws IOException

Read keyed state from an operator in a Savepoint.

Type Parameters:: K - The type of the key in state.; OUT - The output type of the transform function.
Parameters:: identifier - The identifier of the operator.; function - The KeyedStateReaderFunction that is called for each key in state.
Returns:: A DataStream of objects read from keyed state.
Throws:: IOException - If the savepoint does not contain operator state with the given uid.

readKeyedState

public <K,OUT> org.apache.flink.streaming.api.datastream.DataStream<OUT> readKeyedState(OperatorIdentifier identifier,
                                                                                              KeyedStateReaderFunction<K,OUT> function,
                                                                                              org.apache.flink.api.common.typeinfo.TypeInformation<K> keyTypeInfo,
                                                                                              org.apache.flink.api.common.typeinfo.TypeInformation<OUT> outTypeInfo)
                                                                                       throws IOException

Read keyed state from an operator in a Savepoint.

Type Parameters:: K - The type of the key in state.; OUT - The output type of the transform function.
Parameters:: identifier - The identifier of the operator.; function - The KeyedStateReaderFunction that is called for each key in state.; keyTypeInfo - The type information of the key in state.; outTypeInfo - The type information of the output of the transform reader function.
Returns:: A DataStream of objects read from keyed state.
Throws:: IOException - If the savepoint does not contain operator state with the given uid.

window
```
public <W extends org.apache.flink.streaming.api.windowing.windows.Window> WindowSavepointReader<W> window(org.apache.flink.streaming.api.windowing.assigners.WindowAssigner<?,W> assigner)
```
Read window state from an operator in a Savepoint. This method supports reading from any type of window.

Parameters:

assigner - The WindowAssigner used to write out the operator.

Returns:

A WindowSavepointReader.

window
```
public <W extends org.apache.flink.streaming.api.windowing.windows.Window> WindowSavepointReader<W> window(org.apache.flink.api.common.typeutils.TypeSerializer<W> windowSerializer)
```
Read window state from an operator in a Savepoint. This method supports reading from any type of window.

Parameters:

windowSerializer - The serializer used for the window type.

Returns:

A WindowSavepointReader.

Class SavepointReader

Method Summary

Methods inherited from class java.lang.Object

Method Detail

read

read

readListState

readListState

readUnionState

readUnionState

readBroadcastState

readBroadcastState

readKeyedState

readKeyedState

window

window