org.apache.hadoop.hbase.wal

Class RegionGroupingProvider

java.lang.Object

org.apache.hadoop.hbase.wal.RegionGroupingProvider

All Implemented Interfaces:

WALProvider

@InterfaceAudience.Private
public class RegionGroupingProvider
extends Object
implements WALProvider

A WAL Provider that returns a WAL per group of regions. This provider follows the decorator pattern and mainly holds the logic for WAL grouping. WAL creation/roll/close is delegated to DELEGATE_PROVIDER Region grouping is handled via RegionGroupingProvider.RegionGroupingStrategy and can be configured via the property "hbase.wal.regiongrouping.strategy". Current strategy choices are

• defaultStrategy : Whatever strategy this version of HBase picks. currently "bounded".
• identity : each region belongs to its own group.
• bounded : bounded number of groups and region evenly assigned to each group.

Optionally, a FQCN to a custom implementation may be given.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
(package private) static class	RegionGroupingProvider.IdentityGroupingStrategy
static interface	RegionGroupingProvider.RegionGroupingStrategy Map identifiers to a group number.
(package private) static class	RegionGroupingProvider.Strategies Maps between configuration names for strategies and implementation classes.

Nested classes/interfaces inherited from interface org.apache.hadoop.hbase.wal.WALProvider

WALProvider.AsyncWriter, WALProvider.Writer, WALProvider.WriterBase

Field Summary

Fields

Modifier and Type	Field and Description
private ConcurrentMap<String,WALProvider>	cached A group-provider mapping, make sure one-one rather than many-one mapping
private KeyLocker<String>	createLock
static String	DEFAULT_DELEGATE_PROVIDER
static String	DEFAULT_REGION_GROUPING_STRATEGY
static String	DELEGATE_PROVIDER delegate provider for WAL creation/roll/close
private WALFactory	factory
private List<WALActionsListener>	listeners
private static org.slf4j.Logger	LOG
private static String	META_WAL_GROUP_NAME
private Class<? extends WALProvider>	providerClass
private String	providerId
static String	REGION_GROUPING_STRATEGY
private RegionGroupingProvider.RegionGroupingStrategy	strategy

Constructor Summary

Constructors

Constructor and Description
RegionGroupingProvider()

Method Summary

Modifier and Type	Method and Description
void	addWALActionsListener(WALActionsListener listener) Add a WALActionsListener.
void	close() shutdown utstanding WALs and clean up any persisted state.
private WALProvider	createProvider(String group)
long	getLogFileSize() Get size of the log files this provider is managing
long	getNumLogFiles() Get number of the log files this provider is managing
(package private) RegionGroupingProvider.RegionGroupingStrategy	getStrategy(org.apache.hadoop.conf.Configuration conf, String key, String defaultValue) instantiate a strategy from a config property.
WAL	getWAL(RegionInfo region)
private WAL	getWAL(String group)
List<WAL>	getWALs()
void	init(WALFactory factory, org.apache.hadoop.conf.Configuration conf, String providerId) Set up the provider to create wals.
void	shutdown() persist outstanding WALs to storage and stop accepting new appends.

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.hadoop.hbase.wal.WALProvider

getWALFileLengthProvider

Field Detail

LOG

private static final org.slf4j.Logger LOG

REGION_GROUPING_STRATEGY

public static final String REGION_GROUPING_STRATEGY

See Also:

Constant Field Values

DEFAULT_REGION_GROUPING_STRATEGY

public static final String DEFAULT_REGION_GROUPING_STRATEGY

DELEGATE_PROVIDER

public static final String DELEGATE_PROVIDER

delegate provider for WAL creation/roll/close

See Also:

Constant Field Values

DEFAULT_DELEGATE_PROVIDER

public static final String DEFAULT_DELEGATE_PROVIDER

META_WAL_GROUP_NAME

private static final String META_WAL_GROUP_NAME

See Also:

Constant Field Values

cached

private final ConcurrentMap<String,WALProvider> cached

A group-provider mapping, make sure one-one rather than many-one mapping

createLock

private final KeyLocker<String> createLock

strategy

private RegionGroupingProvider.RegionGroupingStrategy strategy

factory

private WALFactory factory

listeners

private List<WALActionsListener> listeners

providerId

private String providerId

providerClass

private Class<? extends WALProvider> providerClass

Constructor Detail

RegionGroupingProvider

public RegionGroupingProvider()

Method Detail

getStrategy

RegionGroupingProvider.RegionGroupingStrategy getStrategy(org.apache.hadoop.conf.Configuration conf,
                                                          String key,
                                                          String defaultValue)
                                                   throws IOException

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

Throws:

IOException

init

public void init(WALFactory factory,
                 org.apache.hadoop.conf.Configuration conf,
                 String providerId)
          throws IOException

Description copied from interface: WALProvider

Set up the provider to create wals. will only be called once per instance.

Specified by:

init in interface WALProvider

Parameters:

factory - factory that made us may not be null

conf - may not be null

providerId - differentiate between providers from one factory. may be null

Throws:

IOException

createProvider

private WALProvider createProvider(String group)
                            throws IOException

Throws:

IOException

getWALs

public List<WAL> getWALs()

Specified by:

getWALs in interface WALProvider

Returns:

the List of WALs that are used by this server

getWAL

private WAL getWAL(String group)
            throws IOException

Throws:

IOException

getWAL

public WAL getWAL(RegionInfo region)
           throws IOException

Specified by:

getWAL in interface WALProvider

Parameters:

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

Returns:

a WAL for writing entries for the given region.

Throws:

IOException

shutdown

public void shutdown()
              throws IOException

Description copied from interface: WALProvider

persist outstanding WALs to storage and stop accepting new appends. This method serves as shorthand for sending a sync to every WAL provided by a given implementation. Those WALs will also stop accepting new writes.

Specified by:

shutdown in interface WALProvider

Throws:

IOException

close

public void close()
           throws IOException

Description copied from interface: WALProvider

shutdown utstanding WALs and clean up any persisted state. Call this method only when you will not need to replay any of the edits to the WALs from this provider. After this call completes, the underlying resources should have been reclaimed.

Specified by:

close in interface WALProvider

Throws:

IOException

getNumLogFiles

public long getNumLogFiles()

Description copied from interface: WALProvider

Get number of the log files this provider is managing

Specified by:

getNumLogFiles in interface WALProvider

getLogFileSize

public long getLogFileSize()

Description copied from interface: WALProvider

Get size of the log files this provider is managing

Specified by:

getLogFileSize in interface WALProvider

addWALActionsListener

public void addWALActionsListener(WALActionsListener listener)

Description copied from interface: WALProvider

Add a WALActionsListener.

Notice that you must call this method before calling WALProvider.getWAL(RegionInfo) as this method will not effect the WAL which has already been created. And as long as we can only it when initialization, it is not thread safe.

Specified by:

addWALActionsListener in interface WALProvider