org.apache.hadoop.hbase.wal

Class IOTestProvider

java.lang.Object

org.apache.hadoop.hbase.wal.IOTestProvider

All Implemented Interfaces:

WALProvider

@InterfaceAudience.Private
public class IOTestProvider
extends Object
implements WALProvider

A WAL Provider that returns a single thread safe WAL that optionally can skip parts of our normal interactions with HDFS. This implementation picks a directory in HDFS based on the same mechanisms as the DefaultWALProvider. Users can configure how much interaction we have with HDFS with the configuration property "hbase.wal.iotestprovider.operations". The value should be a comma separated list of allowed operations:

• append : edits will be written to the underlying filesystem
• sync : wal syncs will result in hflush calls
• fileroll : roll requests will result in creating a new file on the underlying filesystem.

Additionally, the special cases "all" and "none" are recognized. If ommited, the value defaults to "all." Behavior is undefined if "all" or "none" are paired with additional values. Behavior is also undefined if values not listed above are included. Only those operations listed will occur between the returned WAL and HDFS. All others will be no-ops. Note that in the case of allowing "append" operations but not allowing "fileroll", the returned WAL will just keep writing to the same file. This won't avoid all costs associated with file management over time, becaue the data set size may result in additional HDFS block allocations.

Nested Class Summary

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

WALProvider.Writer

Constructor Summary

Constructors

Constructor and Description
IOTestProvider()

Method Summary

Modifier and Type	Method and Description
void	close() shutdown utstanding WALs and clean up any persisted state.
WAL	getWAL(byte[] identifier)
void	init(WALFactory factory, Configuration conf, List<WALActionsListener> listeners, 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

Constructor Detail

IOTestProvider

public IOTestProvider()

Method Detail

init

public void init(WALFactory factory,
                 Configuration conf,
                 List<WALActionsListener> listeners,
                 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, identity used for FS layout. may not be null

conf - may not be null

listeners - may be null

providerId - differentiate between providers from one facotry, used for FS layout. may be null

Throws:

IOException

getWAL

public WAL getWAL(byte[] identifier)
           throws IOException

Specified by:

getWAL in interface WALProvider

Parameters:

identifier - may not be null. contents will not be altered.

Returns:

a WAL for writing entries for the given region.

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

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