org.apache.hadoop.hbase.wal

Class IOTestProvider

java.lang.Object

org.apache.hadoop.hbase.wal.IOTestProvider

public class IOTestProvider
extends Object

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.

Constructor Summary

Constructors

Constructor and Description
IOTestProvider()

Method Summary

Modifier and Type	Method and Description
void	close()
WAL	getWAL(byte[] identifier)
void	init(WALFactory factory, Configuration conf, List<WALActionsListener> listeners, String providerId)
void	shutdown()

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

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

Throws:

IOException

close

public void close()
           throws IOException

Throws:

IOException

shutdown

public void shutdown()
              throws IOException

Throws:

IOException