org.apache.hadoop.hbase.wal

Class WALFactory

java.lang.Object

org.apache.hadoop.hbase.wal.WALFactory

@InterfaceAudience.Private
public class WALFactory
extends Object

Entry point for users of the Write Ahead Log. Acts as the shim between internal use and the particular WALProvider we use to handle wal requests. Configure which provider gets used with the configuration setting "hbase.wal.provider". Available implementations:

• defaultProvider : whatever provider is standard for the hbase version. Currently "asyncfs"
• asyncfs : a provider that will run on top of an implementation of the Hadoop FileSystem interface via an asynchronous client.
• filesystem : a provider that will run on top of an implementation of the Hadoop FileSystem interface via HDFS's synchronous DFSClient.
• multiwal : a provider that will use multiple "filesystem" wal instances per region server.

Alternatively, you may provide a custom implementation of WALProvider by class name.

Field Summary

Fields

Modifier and Type	Field and Description
static String	META_WAL_PROVIDER
static String	WAL_ENABLED
static String	WAL_PROVIDER
static String	WAL_STREAM_READER_CLASS_IMPL Used in tests for injecting customized stream reader implementation, for example, inject fault when reading, etc.

Constructor Summary

Constructors

Constructor and Description
WALFactory(org.apache.hadoop.conf.Configuration conf, String factoryId)
WALFactory(org.apache.hadoop.conf.Configuration conf, String factoryId, Abortable abortable)

Method Summary

Modifier and Type	Method and Description
void	close() Shutdown all WALs and clean up any underlying storage.
WALProvider.Writer	createRecoveredEditsWriter(org.apache.hadoop.fs.FileSystem fs, org.apache.hadoop.fs.Path path) Should be package-private, visible for recovery testing.
WALStreamReader	createStreamReader(org.apache.hadoop.fs.FileSystem fs, org.apache.hadoop.fs.Path path)
WALStreamReader	createStreamReader(org.apache.hadoop.fs.FileSystem fs, org.apache.hadoop.fs.Path path, CancelableProgressable reporter) Create a one-way stream reader for the WAL.
WALStreamReader	createStreamReader(org.apache.hadoop.fs.FileSystem fs, org.apache.hadoop.fs.Path path, CancelableProgressable reporter, long startPosition) Create a one-way stream reader for the WAL, and start reading from the given startPosition.
static WALStreamReader	createStreamReader(org.apache.hadoop.fs.FileSystem fs, org.apache.hadoop.fs.Path path, org.apache.hadoop.conf.Configuration conf) Create a one-way stream reader for a given path.
static WALStreamReader	createStreamReader(org.apache.hadoop.fs.FileSystem fs, org.apache.hadoop.fs.Path path, org.apache.hadoop.conf.Configuration conf, long startPosition) Create a one-way stream reader for a given path.
static WALTailingReader	createTailingReader(org.apache.hadoop.fs.FileSystem fs, org.apache.hadoop.fs.Path path, org.apache.hadoop.conf.Configuration conf, long startPosition) Create a tailing reader for the given path.
WALProvider.Writer	createWALWriter(org.apache.hadoop.fs.FileSystem fs, org.apache.hadoop.fs.Path path) Create a writer for the WAL.
static WALProvider.Writer	createWALWriter(org.apache.hadoop.fs.FileSystem fs, org.apache.hadoop.fs.Path path, org.apache.hadoop.conf.Configuration configuration) If you already have a WALFactory, you should favor the instance method.
ExcludeDatanodeManager	getExcludeDatanodeManager()
String	getFactoryId()
static WALFactory	getInstance(org.apache.hadoop.conf.Configuration configuration)
WALProvider	getMetaProvider() Called when we lazily create a hbase:meta WAL OR from ReplicationSourceManager ahead of creating the first hbase:meta WAL so we can register a listener.
WALProvider	getMetaWALProvider()
Class<? extends WALProvider>	getProviderClass(String key, String defaultValue)
WAL	getWAL(RegionInfo region)
WALProvider	getWALProvider()
List<WAL>	getWALs()
void	shutdown() Tell the underlying WAL providers to shut down, but do not clean up underlying storage.

Methods inherited from class java.lang.Object

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

Field Detail

WAL_STREAM_READER_CLASS_IMPL

public static final String WAL_STREAM_READER_CLASS_IMPL

Used in tests for injecting customized stream reader implementation, for example, inject fault when reading, etc.

After removing the sequence file based WAL, we always use protobuf based WAL reader, and we will also determine whether the WAL file is encrypted and we should use SecureWALCellCodec to decode by check the header of the WAL file, so we do not need to specify a specical reader to read the WAL file either.

So typically you should not use this config in production.

See Also:

Constant Field Values

WAL_PROVIDER

public static final String WAL_PROVIDER

See Also:

Constant Field Values

META_WAL_PROVIDER

public static final String META_WAL_PROVIDER

See Also:

Constant Field Values

WAL_ENABLED

public static final String WAL_ENABLED

See Also:

Constant Field Values

Constructor Detail

WALFactory

public WALFactory(org.apache.hadoop.conf.Configuration conf,
                  String factoryId)
           throws IOException

Throws:

IOException

WALFactory

public WALFactory(org.apache.hadoop.conf.Configuration conf,
                  String factoryId,
                  Abortable abortable)
           throws IOException

Parameters:

conf - must not be null, will keep a reference to read params in later reader/writer instances.

abortable - the server to abort

Throws:

IOException

Method Detail

getProviderClass

public Class<? extends WALProvider> getProviderClass(String key,
                                                     String defaultValue)

close

public void close()
           throws IOException

Shutdown all WALs and clean up any underlying storage. Use only when you will not need to replay and edits that have gone to any wals from this factory.

Throws:

IOException

shutdown

public void shutdown()
              throws IOException

Tell the underlying WAL providers to shut down, but do not clean up underlying storage. If you are not ending cleanly and will need to replay edits from this factory's wals, use this method if you can as it will try to leave things as tidy as possible.

Throws:

IOException

getWALs

public List<WAL> getWALs()

getMetaProvider

public WALProvider getMetaProvider()
                            throws IOException

Called when we lazily create a hbase:meta WAL OR from ReplicationSourceManager ahead of creating the first hbase:meta WAL so we can register a listener.

Throws:

IOException

See Also:

getMetaWALProvider()

getWAL

public WAL getWAL(RegionInfo region)
           throws IOException

Parameters:

region - the region which we want to get a WAL for. Could be null.

Throws:

IOException

createStreamReader

public WALStreamReader createStreamReader(org.apache.hadoop.fs.FileSystem fs,
                                          org.apache.hadoop.fs.Path path)
                                   throws IOException

Throws:

IOException

createStreamReader

public WALStreamReader createStreamReader(org.apache.hadoop.fs.FileSystem fs,
                                          org.apache.hadoop.fs.Path path,
                                          CancelableProgressable reporter)
                                   throws IOException

Create a one-way stream reader for the WAL.

Returns:

A WAL reader. Close when done with it.

Throws:

IOException

createStreamReader

public WALStreamReader createStreamReader(org.apache.hadoop.fs.FileSystem fs,
                                          org.apache.hadoop.fs.Path path,
                                          CancelableProgressable reporter,
                                          long startPosition)
                                   throws IOException

Create a one-way stream reader for the WAL, and start reading from the given startPosition.

Returns:

A WAL reader. Close when done with it.

Throws:

IOException

createWALWriter

public WALProvider.Writer createWALWriter(org.apache.hadoop.fs.FileSystem fs,
                                          org.apache.hadoop.fs.Path path)
                                   throws IOException

Create a writer for the WAL. Uses defaults.

Should be package-private. public only for tests and Compressor

Returns:

A WAL writer. Close when done with it.

Throws:

IOException

createRecoveredEditsWriter

public WALProvider.Writer createRecoveredEditsWriter(org.apache.hadoop.fs.FileSystem fs,
                                                     org.apache.hadoop.fs.Path path)
                                              throws IOException

Should be package-private, visible for recovery testing. Uses defaults.

Returns:

an overwritable writer for recovered edits. caller should close.

Throws:

IOException

getInstance

public static WALFactory getInstance(org.apache.hadoop.conf.Configuration configuration)

createTailingReader

public static WALTailingReader createTailingReader(org.apache.hadoop.fs.FileSystem fs,
                                                   org.apache.hadoop.fs.Path path,
                                                   org.apache.hadoop.conf.Configuration conf,
                                                   long startPosition)
                                            throws IOException

Create a tailing reader for the given path. Mainly used in replication.

Throws:

IOException

createStreamReader

public static WALStreamReader createStreamReader(org.apache.hadoop.fs.FileSystem fs,
                                                 org.apache.hadoop.fs.Path path,
                                                 org.apache.hadoop.conf.Configuration conf)
                                          throws IOException

Create a one-way stream reader for a given path.

Throws:

IOException

createStreamReader

public static WALStreamReader createStreamReader(org.apache.hadoop.fs.FileSystem fs,
                                                 org.apache.hadoop.fs.Path path,
                                                 org.apache.hadoop.conf.Configuration conf,
                                                 long startPosition)
                                          throws IOException

Create a one-way stream reader for a given path.

Throws:

IOException

createWALWriter

public static WALProvider.Writer createWALWriter(org.apache.hadoop.fs.FileSystem fs,
                                                 org.apache.hadoop.fs.Path path,
                                                 org.apache.hadoop.conf.Configuration configuration)
                                          throws IOException

If you already have a WALFactory, you should favor the instance method. Uses defaults.

Returns:

a writer that won't overwrite files. Caller must close.

Throws:

IOException

getFactoryId

public String getFactoryId()

getWALProvider

public WALProvider getWALProvider()

getMetaWALProvider

public WALProvider getMetaWALProvider()

Returns:

Current metaProvider... may be null if not yet initialized.

See Also:

getMetaProvider()

getExcludeDatanodeManager

public ExcludeDatanodeManager getExcludeDatanodeManager()