Package org.apache.hadoop.hdfs.server.federation.store

Class StateStoreService

java.lang.Object
org.apache.hadoop.service.AbstractService
org.apache.hadoop.service.CompositeService
org.apache.hadoop.hdfs.server.federation.store.StateStoreService
All Implemented Interfaces:
Closeable, AutoCloseable, org.apache.hadoop.service.Service
@Private @Evolving public class StateStoreService extends org.apache.hadoop.service.CompositeService
A service to initialize a StateStoreDriver and maintain the connection to the data store. There are multiple state store driver connections supported:

The service also supports the dynamic registration of record stores like:

  • Nested Class Summary

    Nested classes/interfaces inherited from class org.apache.hadoop.service.CompositeService

    org.apache.hadoop.service.CompositeService.CompositeServiceShutdownHook

    Nested classes/interfaces inherited from interface org.apache.hadoop.service.Service

    org.apache.hadoop.service.Service.STATE

  • Field Summary

    Fields inherited from class org.apache.hadoop.service.CompositeService

    STOP_ONLY_STARTED_SERVICES

  • Constructor Summary

    Constructors
    Constructor
    Description
    StateStoreService()
     

  • Method Summary

    Modifier and Type
    Method
    Description
    void
    closeDriver()
    Manually shuts down the driver.
    long
    getCacheUpdateTime()
    The last time the state store cache was fully updated.
    StateStoreDriver
    getDriver()
    Get the state store driver.
    String
    getIdentifier()
    Fetch a unique identifier for this state store instance.
    StateStoreMetrics
    getMetrics()
    Get the metrics for the State Store.
    <T extends RecordStore<? extends BaseRecord>>
    List<T>
    getRecordStores()
    Get the list of all RecordStores.
    <T extends RecordStore<?>>
    T
    getRegisteredRecordStore(Class<T> recordStoreClass)
    Get the record store in this State Store for a given interface.
    Collection<Class<? extends BaseRecord>>
    getSupportedRecords()
    List of records supported by this State Store.
    boolean
    isDriverReady()
    Check if the driver is ready to be used.
    boolean
    loadCache(Class<?> clazz)
    Update the cache for a specific record store.
    boolean
    loadCache(Class<?> clazz, boolean force)
    Update the cache for a specific record store.
    void
    loadDriver()
    Load the State Store driver.
    void
    refreshCaches()
    Refresh the cache with information from the State Store.
    void
    refreshCaches(boolean force)
    Refresh the cache with information from the State Store.
    void
    registerCacheExternal(StateStoreCache client)
    Register a cached record store for automatic periodic cache updates.
    protected void
    serviceInit(org.apache.hadoop.conf.Configuration config)
    Initialize the State Store and the connection to the back-end.
    protected void
    serviceStart()
     
    protected void
    serviceStop()
     
    void
    setIdentifier(String id)
    Set a unique synchronization identifier for this store.
    void
    stopCacheUpdateService()
    Stops the cache update service.

    Methods inherited from class org.apache.hadoop.service.CompositeService

    addIfService, addService, getServices, removeService

    Methods inherited from class org.apache.hadoop.service.AbstractService

    close, getBlockers, getConfig, getFailureCause, getFailureState, getLifecycleHistory, getName, getServiceState, getStartTime, init, isInState, noteFailure, putBlocker, registerGlobalListener, registerServiceListener, removeBlocker, setConfig, start, stop, toString, unregisterGlobalListener, unregisterServiceListener, waitForServiceToStop

    Methods inherited from class java.lang.Object

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

  • Constructor Details

    • StateStoreService

      public StateStoreService()

  • Method Details

    • serviceInit

      protected void serviceInit(org.apache.hadoop.conf.Configuration config) throws Exception
      Initialize the State Store and the connection to the back-end.
      Overrides:
      serviceInit in class org.apache.hadoop.service.CompositeService
      Parameters:
      config - Configuration for the State Store.
      Throws:
      Exception - Cannot create driver for the State Store.

    • serviceStart

      protected void serviceStart() throws Exception
      Overrides:
      serviceStart in class org.apache.hadoop.service.CompositeService
      Throws:
      Exception

    • serviceStop

      protected void serviceStop() throws Exception
      Overrides:
      serviceStop in class org.apache.hadoop.service.CompositeService
      Throws:
      Exception

    • getRegisteredRecordStore

      public <T extends RecordStore<?>> T getRegisteredRecordStore(Class<T> recordStoreClass)
      Get the record store in this State Store for a given interface.
      Type Parameters:
      T - The type of the record store.
      Parameters:
      recordStoreClass - Class of the record store.
      Returns:
      Registered record store or null if not found.

    • getRecordStores

      public <T extends RecordStore<? extends BaseRecord>> List<T> getRecordStores()
      Get the list of all RecordStores.
      Type Parameters:
      T - The type of the record stores that are returned.
      Returns:
      a list of each RecordStore.

    • getSupportedRecords

      public Collection<Class<? extends BaseRecord>> getSupportedRecords()
      List of records supported by this State Store.
      Returns:
      List of supported record classes.

    • loadDriver

      public void loadDriver()
      Load the State Store driver. If successful, refresh cached data tables.

    • isDriverReady

      public boolean isDriverReady()
      Check if the driver is ready to be used.
      Returns:
      If the driver is ready.

    • closeDriver

      @VisibleForTesting public void closeDriver() throws Exception
      Manually shuts down the driver.
      Throws:
      Exception - If the driver cannot be closed.

    • getDriver

      public StateStoreDriver getDriver()
      Get the state store driver.
      Returns:
      State store driver.

    • getIdentifier

      public String getIdentifier()
      Fetch a unique identifier for this state store instance. Typically, it is the address of the router.
      Returns:
      Unique identifier for this store.

    • setIdentifier

      public void setIdentifier(String id)
      Set a unique synchronization identifier for this store.
      Parameters:
      id - Unique identifier, typically the router's RPC address.

    • getCacheUpdateTime

      public long getCacheUpdateTime()
      The last time the state store cache was fully updated.
      Returns:
      Timestamp.

    • stopCacheUpdateService

      @VisibleForTesting public void stopCacheUpdateService()
      Stops the cache update service.

    • registerCacheExternal

      public void registerCacheExternal(StateStoreCache client)
      Register a cached record store for automatic periodic cache updates.
      Parameters:
      client - Client to the state store.

    • refreshCaches

      public void refreshCaches()
      Refresh the cache with information from the State Store. Called periodically by the CacheUpdateService to maintain data caches and versions.

    • refreshCaches

      public void refreshCaches(boolean force)
      Refresh the cache with information from the State Store. Called periodically by the CacheUpdateService to maintain data caches and versions.
      Parameters:
      force - If we force the refresh.

    • loadCache

      public boolean loadCache(Class<?> clazz) throws IOException
      Update the cache for a specific record store.
      Parameters:
      clazz - Class of the record store.
      Returns:
      If the cached was loaded.
      Throws:
      IOException - if the cache update failed.

    • loadCache

      public boolean loadCache(Class<?> clazz, boolean force) throws IOException
      Update the cache for a specific record store.
      Parameters:
      clazz - Class of the record store.
      force - Force the update ignoring cached periods.
      Returns:
      If the cached was loaded.
      Throws:
      IOException - if the cache update failed.

    • getMetrics

      public StateStoreMetrics getMetrics()
      Get the metrics for the State Store.
      Returns:
      State Store metrics.