org.apache.iotdb.db.writelog.node

接口 WriteLogNode

所有已知实现类:

ExclusiveWriteLogNode

public interface WriteLogNode

WriteLogNode is the minimum unit of managing WALs.

方法概要

限定符和类型	方法和说明
void	close() Sync and close streams.
ByteBuffer[]	delete() Abandon all logs in this node and delete the log directory.
void	forceSync() Write what in cache to disk.
String	getIdentifier() return identifier of the log node.
String	getLogDirectory() return the directory where wal files of this node are placed.
ILogReader	getLogReader() return an ILogReader which can iterate each log in this log node.
void	initBuffer(ByteBuffer[] byteBuffers) init the buffers, this should be called after this node being created.
void	notifyEndFlush() When data that have WALs in this node end flushing, this method must be called to check and remove the out-dated logs file.
void	notifyStartFlush() When data that have WALs in this node start to be flushed, this method must be called to change the working WAL file.
void	release() Release the resource it occupies.
void	write(PhysicalPlan plan) Write a wal for a PhysicalPlan.

方法详细资料

write

void write(PhysicalPlan plan)
    throws IOException

Write a wal for a PhysicalPlan. First, the PhysicalPlan will be conveyed to byte[]. Then the byte[] will be put into a cache. When the cache is full, the logs in the cache will be synced to disk.

参数:

plan - - a PhysicalPlan

抛出:

IOException

close

void close()
    throws IOException

Sync and close streams.

抛出:

IOException

release

void release()

Release the resource it occupies. After this method is invoked, this node should be no longer to used

forceSync

void forceSync()
        throws IOException

Write what in cache to disk.

抛出:

IOException

notifyStartFlush

void notifyStartFlush()
               throws IOException

When data that have WALs in this node start to be flushed, this method must be called to change the working WAL file.

抛出:

IOException

notifyEndFlush

void notifyEndFlush()

When data that have WALs in this node end flushing, this method must be called to check and remove the out-dated logs file.

getIdentifier

String getIdentifier()

return identifier of the log node.

返回:

The identifier of this log node.

getLogDirectory

String getLogDirectory()

return the directory where wal files of this node are placed.

返回:

The directory where wal files of this node are placed.

delete

ByteBuffer[] delete()
             throws IOException

Abandon all logs in this node and delete the log directory. Calling insert() after calling this method is undefined.

抛出:

IOException

getLogReader

ILogReader getLogReader()

return an ILogReader which can iterate each log in this log node.

返回:

an ILogReader which can iterate each log in this log node.

initBuffer

void initBuffer(ByteBuffer[] byteBuffers)

init the buffers, this should be called after this node being created.