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.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
(package private) static class	WALFactory.Providers Maps between configuration names for providers and implementation classes.

Field Summary

Fields

Modifier and Type	Field and Description
private org.apache.hadoop.conf.Configuration	conf
(package private) static String	DEFAULT_WAL_PROVIDER
(package private) String	factoryId
private static org.slf4j.Logger	LOG
private Class<? extends AbstractFSWALProvider.Reader>	logReaderClass Configuration-specified WAL Reader used when a custom reader is requested
static String	META_WAL_PROVIDER
private AtomicReference<WALProvider>	metaProvider
private WALProvider	provider
private static AtomicReference<WALFactory>	singleton
private static String	SINGLETON_ID
private int	timeoutMillis How long to attempt opening in-recovery wals
static String	WAL_ENABLED
static String	WAL_PROVIDER

Constructor Summary

Constructors

Modifier	Constructor and Description
private	WALFactory(org.apache.hadoop.conf.Configuration conf)
	WALFactory(org.apache.hadoop.conf.Configuration conf, String factoryId)

Method Summary

Modifier and Type	Method and Description
void	close() Shutdown all WALs and clean up any underlying storage.
(package private) WALProvider	createProvider(Class<? extends WALProvider> clazz, String providerId)
WAL.Reader	createReader(org.apache.hadoop.fs.FileSystem fs, org.apache.hadoop.fs.Path path)
WAL.Reader	createReader(org.apache.hadoop.fs.FileSystem fs, org.apache.hadoop.fs.Path path, CancelableProgressable reporter) Create a reader for the WAL.
WAL.Reader	createReader(org.apache.hadoop.fs.FileSystem fs, org.apache.hadoop.fs.Path path, CancelableProgressable reporter, boolean allowCustom)
static WAL.Reader	createReader(org.apache.hadoop.fs.FileSystem fs, org.apache.hadoop.fs.Path path, org.apache.hadoop.conf.Configuration configuration) Create a reader for the given path, accept custom reader classes from conf.
(package private) static WAL.Reader	createReader(org.apache.hadoop.fs.FileSystem fs, org.apache.hadoop.fs.Path path, org.apache.hadoop.conf.Configuration configuration, CancelableProgressable reporter) Create a reader for the given path, accept custom reader classes from conf.
static WAL.Reader	createReaderIgnoreCustomClass(org.apache.hadoop.fs.FileSystem fs, org.apache.hadoop.fs.Path path, org.apache.hadoop.conf.Configuration configuration) Create a reader for the given path, ignore custom reader classes from conf.
WALProvider.Writer	createRecoveredEditsWriter(org.apache.hadoop.fs.FileSystem fs, org.apache.hadoop.fs.Path path) Should be package-private, visible for recovery testing.
(package private) static WALProvider.Writer	createRecoveredEditsWriter(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.
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.
(package private) WALFactory.Providers	getDefaultProvider()
String	getFactoryId()
static WALFactory	getInstance(org.apache.hadoop.conf.Configuration configuration)
(package private) WALProvider	getMetaProvider()
WALProvider	getMetaWALProvider()
(package private) WALProvider	getProvider(String key, String defaultValue, String providerId) instantiate a provider from a config property.
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

LOG

private static final org.slf4j.Logger LOG

WAL_PROVIDER

public static final String WAL_PROVIDER

See Also:

Constant Field Values

DEFAULT_WAL_PROVIDER

static final String DEFAULT_WAL_PROVIDER

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

factoryId

final String factoryId

provider

private final WALProvider provider

metaProvider

private final AtomicReference<WALProvider> metaProvider

logReaderClass

private final Class<? extends AbstractFSWALProvider.Reader> logReaderClass

Configuration-specified WAL Reader used when a custom reader is requested

timeoutMillis

private final int timeoutMillis

How long to attempt opening in-recovery wals

conf

private final org.apache.hadoop.conf.Configuration conf

singleton

private static final AtomicReference<WALFactory> singleton

SINGLETON_ID

private static final String SINGLETON_ID

Constructor Detail

WALFactory

private WALFactory(org.apache.hadoop.conf.Configuration conf)

WALFactory

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

Parameters:

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

factoryId - a unique identifier for this factory. used i.e. by filesystem implementations to make a directory

Throws:

IOException

Method Detail

getDefaultProvider

WALFactory.Providers getDefaultProvider()

getProviderClass

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

createProvider

WALProvider createProvider(Class<? extends WALProvider> clazz,
                           String providerId)
                    throws IOException

Throws:

IOException

getProvider

WALProvider getProvider(String key,
                        String defaultValue,
                        String providerId)
                 throws IOException

instantiate a provider from a config property. requires conf to have already been set (as well as anything the provider might need to read).

Throws:

IOException

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

WALProvider getMetaProvider()
                     throws IOException

Throws:

IOException

getWAL

public WAL getWAL(RegionInfo region)
           throws IOException

Parameters:

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

Throws:

IOException

createReader

public WAL.Reader createReader(org.apache.hadoop.fs.FileSystem fs,
                               org.apache.hadoop.fs.Path path)
                        throws IOException

Throws:

IOException

createReader

public WAL.Reader createReader(org.apache.hadoop.fs.FileSystem fs,
                               org.apache.hadoop.fs.Path path,
                               CancelableProgressable reporter)
                        throws IOException

Create a reader for the WAL. If you are reading from a file that's being written to and need to reopen it multiple times, use WAL.Reader.reset() instead of this method then just seek back to the last known good position.

Returns:

A WAL reader. Close when done with it.

Throws:

IOException

createReader

public WAL.Reader createReader(org.apache.hadoop.fs.FileSystem fs,
                               org.apache.hadoop.fs.Path path,
                               CancelableProgressable reporter,
                               boolean allowCustom)
                        throws IOException

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)

createReader

public static WAL.Reader createReader(org.apache.hadoop.fs.FileSystem fs,
                                      org.apache.hadoop.fs.Path path,
                                      org.apache.hadoop.conf.Configuration configuration)
                               throws IOException

Create a reader for the given path, accept custom reader classes from conf. If you already have a WALFactory, you should favor the instance method.

Returns:

a WAL Reader, caller must close.

Throws:

IOException

createReader

static WAL.Reader createReader(org.apache.hadoop.fs.FileSystem fs,
                               org.apache.hadoop.fs.Path path,
                               org.apache.hadoop.conf.Configuration configuration,
                               CancelableProgressable reporter)
                        throws IOException

Create a reader for the given path, accept custom reader classes from conf. If you already have a WALFactory, you should favor the instance method.

Returns:

a WAL Reader, caller must close.

Throws:

IOException

createReaderIgnoreCustomClass

public static WAL.Reader createReaderIgnoreCustomClass(org.apache.hadoop.fs.FileSystem fs,
                                                       org.apache.hadoop.fs.Path path,
                                                       org.apache.hadoop.conf.Configuration configuration)
                                                throws IOException

Create a reader for the given path, ignore custom reader classes from conf. If you already have a WALFactory, you should favor the instance method. only public pending move of Compressor

Returns:

a WAL Reader, caller must close.

Throws:

IOException

createRecoveredEditsWriter

static WALProvider.Writer createRecoveredEditsWriter(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 will overwrite files. Caller must close.

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 final WALProvider getWALProvider()

getMetaWALProvider

public final WALProvider getMetaWALProvider()