SplitLogManager (Apache HBase 1.4.11 API)

java.lang.Object
- org.apache.hadoop.hbase.master.SplitLogManager

```
@InterfaceAudience.Private
public class SplitLogManager
extends Object
```
Distributes the task of log splitting to the available region servers. Coordination happens via coordination engine. For every log file that has to be split a task is created. SplitLogWorkers race to grab a task.
SplitLogManager monitors the tasks that it creates using the timeoutMonitor thread. If a task's progress is slow then SplitLogManagerCoordination.checkTasks() will take away the task from the owner SplitLogWorker and the task will be up for grabs again. When the task is done then it is deleted by SplitLogManager.
Clients call splitLogDistributed(Path) to split a region server's log files. The caller thread waits in this method until all the log files have been split.
All the coordination calls made by this class are asynchronous. This is mainly to help reduce response time seen by the callers.
There is race in this design between the SplitLogManager and the SplitLogWorker. SplitLogManager might re-queue a task that has in reality already been completed by a SplitLogWorker. We rely on the idempotency of the log splitting task for correctness.
It is also assumed that every log splitting task is unique and once completed (either with success or with error) it will be not be submitted again. If a task is resubmitted then there is a risk that old "delete task" can delete the re-submission.

Nested Class Summary

Nested Classes
Modifier and Type	Class and Description
`static class`	`SplitLogManager.ResubmitDirective`
`static class`	`SplitLogManager.Task` in memory state of an active task.
`static class`	`SplitLogManager.TaskBatch` Keeps track of the batch of tasks submitted together by a caller in splitLogDistributed().
`static class`	`SplitLogManager.TerminationStatus`

Field Summary

Fields
Modifier and Type	Field and Description
`static int`	`DEFAULT_UNASSIGNED_TIMEOUT`
`protected ReentrantLock`	`recoveringRegionLock` In distributedLogReplay mode, we need touch both splitlog and recovering-regions znodes in one operation.

Constructor Summary

Constructors
Constructor and Description
`SplitLogManager(Server server, org.apache.hadoop.conf.Configuration conf, Stoppable stopper, MasterServices master, ServerName serverName)` Its OK to construct this object even when region-servers are not online.

Method Summary

Methods
Modifier and Type	Method and Description
`static org.apache.hadoop.fs.FileStatus[]`	`getFileList(org.apache.hadoop.conf.Configuration conf, List<org.apache.hadoop.fs.Path> logDirs, org.apache.hadoop.fs.PathFilter filter)` Get a list of paths that need to be split given a set of server-specific directories and optionally a filter.
`org.apache.hadoop.hbase.protobuf.generated.ZooKeeperProtos.SplitLogTask.RecoveryMode`	`getRecoveryMode()`
`boolean`	`isLogReplaying()`
`boolean`	`isLogSplitting()`
`void`	`markRegionsRecovering(ServerName server, Set<HRegionInfo> userRegions)`
`void`	`setRecoveryMode(boolean isForInitialization)` This function is to set recovery mode from outstanding split log tasks from before or current configuration setting
`long`	`splitLogDistributed(List<org.apache.hadoop.fs.Path> logDirs)` The caller will block until all the log files of the given region server have been processed - successfully split or an error is encountered - by an available worker region server.
`long`	`splitLogDistributed(org.apache.hadoop.fs.Path logDir)`
`long`	`splitLogDistributed(Set<ServerName> serverNames, List<org.apache.hadoop.fs.Path> logDirs, org.apache.hadoop.fs.PathFilter filter)` The caller will block until all the hbase:meta log files of the given region server have been processed - successfully split or an error is encountered - by an available worker region server.
`void`	`stop()`

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - DEFAULT_UNASSIGNED_TIMEOUT
```
public static final int DEFAULT_UNASSIGNED_TIMEOUT
```
    See Also:
    Constant Field Values
  - recoveringRegionLock
```
protected final ReentrantLock recoveringRegionLock
```
    In distributedLogReplay mode, we need touch both splitlog and recovering-regions znodes in one operation. So the lock is used to guard such cases.
- Constructor Detail
  - SplitLogManager
```
public SplitLogManager(Server server,
               org.apache.hadoop.conf.Configuration conf,
               Stoppable stopper,
               MasterServices master,
               ServerName serverName)
                throws IOException
```
    Its OK to construct this object even when region-servers are not online. It does lookup the orphan tasks in coordination engine but it doesn't block waiting for them to be done.
    
    Parameters:
    server - the server instance
    conf - the HBase configuration
    stopper - the stoppable in case anything is wrong
    master - the master services
    serverName - the master server name
    
    Throws:
    
    IOException
- Method Detail
  - getFileList
```
public static org.apache.hadoop.fs.FileStatus[] getFileList(org.apache.hadoop.conf.Configuration conf,
                                            List<org.apache.hadoop.fs.Path> logDirs,
                                            org.apache.hadoop.fs.PathFilter filter)
                                                     throws IOException
```
    Get a list of paths that need to be split given a set of server-specific directories and optionally a filter. See DefaultWALProvider.getServerNameFromWALDirectoryName(org.apache.hadoop.conf.Configuration, java.lang.String) for more info on directory layout. Should be package-private, but is needed by WALSplitter.split(Path, Path, Path, FileSystem, Configuration, WALFactory) for tests.
    
    Throws:
    
    IOException
  - splitLogDistributed
```
public long splitLogDistributed(org.apache.hadoop.fs.Path logDir)
                         throws IOException
```
    Parameters:
    logDir - one region sever wal dir path in .logs
    
    Returns:
    cumulative size of the logfiles split
    
    Throws:
    
    IOException - if there was an error while splitting any log file
    
    IOException
  - splitLogDistributed
```
public long splitLogDistributed(List<org.apache.hadoop.fs.Path> logDirs)
                         throws IOException
```
    The caller will block until all the log files of the given region server have been processed - successfully split or an error is encountered - by an available worker region server. This method must only be called after the region servers have been brought online.
    
    Parameters:
    logDirs - List of log dirs to split
    
    Returns:
    cumulative size of the logfiles split
    
    Throws:
    
    IOException - If there was an error while splitting any log file
  - splitLogDistributed
```
public long splitLogDistributed(Set<ServerName> serverNames,
                       List<org.apache.hadoop.fs.Path> logDirs,
                       org.apache.hadoop.fs.PathFilter filter)
                         throws IOException
```
    The caller will block until all the hbase:meta log files of the given region server have been processed - successfully split or an error is encountered - by an available worker region server. This method must only be called after the region servers have been brought online.
    
    Parameters:
    logDirs - List of log dirs to split
    filter - the Path filter to select specific files for considering
    
    Returns:
    cumulative size of the logfiles split
    
    Throws:
    
    IOException - If there was an error while splitting any log file
  - stop
```
public void stop()
```
  - setRecoveryMode
```
public void setRecoveryMode(boolean isForInitialization)
                     throws IOException
```
    This function is to set recovery mode from outstanding split log tasks from before or current configuration setting
    
    Parameters:
    isForInitialization -
    
    Throws:
    
    IOException - throws if it's impossible to set recovery mode
  - markRegionsRecovering
```
public void markRegionsRecovering(ServerName server,
                         Set<HRegionInfo> userRegions)
                           throws InterruptedIOException,
                                  IOException
```
    Throws:
    
    InterruptedIOException
    
    IOException
  - isLogReplaying
```
public boolean isLogReplaying()
```
    Returns:
    whether log is replaying
  - isLogSplitting
```
public boolean isLogSplitting()
```
    Returns:
    whether log is splitting
  - getRecoveryMode
```
public org.apache.hadoop.hbase.protobuf.generated.ZooKeeperProtos.SplitLogTask.RecoveryMode getRecoveryMode()
```
    Returns:
    the current log recovery mode

Class SplitLogManager

Nested Class Summary

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

DEFAULT_UNASSIGNED_TIMEOUT

recoveringRegionLock

Constructor Detail

SplitLogManager

Method Detail

getFileList

splitLogDistributed

splitLogDistributed

splitLogDistributed

stop

setRecoveryMode

markRegionsRecovering

isLogReplaying

isLogSplitting

getRecoveryMode