Package org.apache.flink.runtime.state

Class StateBackendLoader

java.lang.Object

org.apache.flink.runtime.state.StateBackendLoader

public class StateBackendLoader
extends Object

This class contains utility methods to load state backends from configurations.

Field Summary

Fields

Modifier and Type	Field	Description
static String	FORST_STATE_BACKEND_NAME
static String	HASHMAP_STATE_BACKEND_NAME	The shortcut configuration name of the HashMap state backend.
static String	ROCKSDB_STATE_BACKEND_NAME	The shortcut configuration name for the RocksDB State Backend.

Method Summary

Modifier and Type	Method	Description
static StateBackend	fromApplicationOrConfigOrDefault(StateBackend fromApplication, org.apache.flink.configuration.Configuration jobConfig, org.apache.flink.configuration.Configuration clusterConfig, ClassLoader classLoader, org.slf4j.Logger logger)	This is the state backend loader that loads a DelegatingStateBackend wrapping the state backend loaded from loadFromApplicationOrConfigOrDefaultInternal(org.apache.flink.runtime.state.StateBackend, org.apache.flink.configuration.Configuration, org.apache.flink.configuration.Configuration, java.lang.ClassLoader, org.slf4j.Logger) when delegation is enabled.
static boolean	isChangelogStateBackend(StateBackend backend)
static StateBackend	loadStateBackendFromConfig(org.apache.flink.configuration.ReadableConfig config, ClassLoader classLoader, org.slf4j.Logger logger)	Loads the unwrapped state backend from the configuration, from the parameter 'state.backend', as defined in StateBackendOptions.STATE_BACKEND.
static StateBackend	loadStateBackendFromKeyedStateHandles(StateBackend originalStateBackend, ClassLoader classLoader, Collection<KeyedStateHandle> keyedStateHandles)	Load state backend which may wrap the original state backend for recovery.
static boolean	stateBackendFromApplicationOrConfigOrDefaultUseManagedMemory(org.apache.flink.configuration.Configuration config, Optional<Boolean> stateBackendFromApplicationUsesManagedMemory, ClassLoader classLoader)	Checks whether state backend uses managed memory, without having to deserialize or load the state backend.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

HASHMAP_STATE_BACKEND_NAME

public static final String HASHMAP_STATE_BACKEND_NAME

The shortcut configuration name of the HashMap state backend.

See Also:

Constant Field Values

ROCKSDB_STATE_BACKEND_NAME

public static final String ROCKSDB_STATE_BACKEND_NAME

The shortcut configuration name for the RocksDB State Backend.

See Also:

Constant Field Values

FORST_STATE_BACKEND_NAME

public static final String FORST_STATE_BACKEND_NAME

See Also:

Constant Field Values

Method Detail

loadStateBackendFromConfig

@Nonnull
public static StateBackend loadStateBackendFromConfig(org.apache.flink.configuration.ReadableConfig config,
                                                      ClassLoader classLoader,
                                                      @Nullable
                                                      org.slf4j.Logger logger)
                                               throws org.apache.flink.configuration.IllegalConfigurationException,
                                                      org.apache.flink.util.DynamicCodeLoadingException,
                                                      IOException

Loads the unwrapped state backend from the configuration, from the parameter 'state.backend', as defined in StateBackendOptions.STATE_BACKEND.

The state backends can be specified either via their shortcut name, or via the class name of a StateBackendFactory. If a StateBackendFactory class name is specified, the factory is instantiated (via its zero-argument constructor) and its StateBackendFactory.createFromConfig(ReadableConfig, ClassLoader) method is called.

Recognized shortcut names are '"hashmap"', '"rocksdb"'

Parameters:

config - The configuration to load the state backend from

classLoader - The class loader that should be used to load the state backend

logger - Optionally, a logger to log actions to (may be null)

Returns:

The instantiated state backend.

Throws:

org.apache.flink.util.DynamicCodeLoadingException - Thrown if a state backend factory is configured and the factory class was not found or the factory could not be instantiated

org.apache.flink.configuration.IllegalConfigurationException - May be thrown by the StateBackendFactory when creating / configuring the state backend in the factory

IOException - May be thrown by the StateBackendFactory when instantiating the state backend

fromApplicationOrConfigOrDefault

public static StateBackend fromApplicationOrConfigOrDefault(@Nullable
                                                            StateBackend fromApplication,
                                                            org.apache.flink.configuration.Configuration jobConfig,
                                                            org.apache.flink.configuration.Configuration clusterConfig,
                                                            ClassLoader classLoader,
                                                            @Nullable
                                                            org.slf4j.Logger logger)
                                                     throws org.apache.flink.configuration.IllegalConfigurationException,
                                                            org.apache.flink.util.DynamicCodeLoadingException,
                                                            IOException

This is the state backend loader that loads a DelegatingStateBackend wrapping the state backend loaded from loadFromApplicationOrConfigOrDefaultInternal(org.apache.flink.runtime.state.StateBackend, org.apache.flink.configuration.Configuration, org.apache.flink.configuration.Configuration, java.lang.ClassLoader, org.slf4j.Logger) when delegation is enabled. If delegation is not enabled, the underlying wrapped state backend is returned instead.

Parameters:

fromApplication - StateBackend defined from application

jobConfig - The job level configuration to load the state backend from

clusterConfig - The cluster level configuration to load the state backend from

classLoader - The class loader that should be used to load the state backend

logger - Optionally, a logger to log actions to (may be null)

Returns:

The instantiated state backend.

Throws:

org.apache.flink.util.DynamicCodeLoadingException - Thrown if a state backend (factory) is configured and the (factory) class was not found or could not be instantiated

org.apache.flink.configuration.IllegalConfigurationException - May be thrown by the StateBackendFactory when creating / configuring the state backend in the factory

IOException - May be thrown by the StateBackendFactory when instantiating the state backend

stateBackendFromApplicationOrConfigOrDefaultUseManagedMemory

public static boolean stateBackendFromApplicationOrConfigOrDefaultUseManagedMemory(org.apache.flink.configuration.Configuration config,
                                                                                   Optional<Boolean> stateBackendFromApplicationUsesManagedMemory,
                                                                                   ClassLoader classLoader)

Checks whether state backend uses managed memory, without having to deserialize or load the state backend.

Parameters:

config - configuration to load the state backend from.

stateBackendFromApplicationUsesManagedMemory - Whether the application-defined backend uses Flink's managed memory. Empty if application has not defined a backend.

classLoader - User code classloader.

Returns:

Whether the state backend uses managed memory.

loadStateBackendFromKeyedStateHandles

public static StateBackend loadStateBackendFromKeyedStateHandles(StateBackend originalStateBackend,
                                                                 ClassLoader classLoader,
                                                                 Collection<KeyedStateHandle> keyedStateHandles)
                                                          throws org.apache.flink.util.DynamicCodeLoadingException

Load state backend which may wrap the original state backend for recovery.

Parameters:

originalStateBackend - StateBackend loaded from application or config.

classLoader - User code classloader.

keyedStateHandles - The state handles for restore.

Returns:

Wrapped state backend for recovery.

Throws:

org.apache.flink.util.DynamicCodeLoadingException - Thrown if keyed state handles of wrapped state backend are found and the class was not found or could not be instantiated.

isChangelogStateBackend

public static boolean isChangelogStateBackend(StateBackend backend)