org.apache.hadoop.hdfs.server.protocol

接口 NamenodeProtocol

所有超级接口:

VersionedProtocol

所有已知实现类:

NameNode

public interface NamenodeProtocol
extends VersionedProtocol

Protocol that a secondary NameNode uses to communicate with the NameNode. It's used to get part of the name node state

字段概要

字段

限定符和类型	字段和说明
static long	versionID 3: new method added: getAccessKeys()

方法概要

方法

限定符和类型	方法和说明
ExportedBlockKeys	getBlockKeys() Get the current block keys
BlocksWithLocations	getBlocks(DatanodeInfo datanode, long size) Get a list of blocks belonged to datanode whose total size is equal to size
long	getEditLogSize() Get the size of the current edit log (in bytes).
CheckpointSignature	rollEditLog() Closes the current edit log and opens a new one.
void	rollFsImage() Rolls the fsImage log.

从接口继承的方法 org.apache.hadoop.ipc.VersionedProtocol

getProtocolVersion

字段详细资料

versionID

static final long versionID

3: new method added: getAccessKeys()

另请参阅:

常量字段值

方法详细资料

getBlocks

BlocksWithLocations getBlocks(DatanodeInfo datanode,
                            long size)
                              throws IOException

Get a list of blocks belonged to datanode whose total size is equal to size

参数:

datanode - a data node

size - requested size

返回:

a list of blocks & their locations

抛出:

RemoteException - if size is less than or equal to 0 or datanode does not exist

IOException

getBlockKeys

ExportedBlockKeys getBlockKeys()
                               throws IOException

Get the current block keys

返回:

ExportedBlockKeys containing current block keys

抛出:

IOException

getEditLogSize

long getEditLogSize()
                    throws IOException

Get the size of the current edit log (in bytes).

返回:

The number of bytes in the current edit log.

抛出:

IOException

rollEditLog

CheckpointSignature rollEditLog()
                                throws IOException

Closes the current edit log and opens a new one. The call fails if the file system is in SafeMode.

返回:

a unique token to identify this transaction.

抛出:

IOException

rollFsImage

void rollFsImage()
                 throws IOException

Rolls the fsImage log. It removes the old fsImage, copies the new image to fsImage, removes the old edits and renames edits.new to edits. The call fails if any of the four files are missing.

抛出:

IOException