CommitLog (apache-cassandra API)

java.lang.Object
- org.apache.cassandra.db.commitlog.CommitLog

All Implemented Interfaces:: CommitLogMBean

public class CommitLog
extends java.lang.Object
implements CommitLogMBean

Field Summary

Fields
Modifier and Type	Field and Description
`CommitLogSegment`	`activeSegment`
`CommitLogAllocator`	`allocator`
`CommitLogArchiver`	`archiver`
`static int`	`END_OF_SEGMENT_MARKER`
`static int`	`END_OF_SEGMENT_MARKER_SIZE`
`static CommitLog`	`instance`

Method Summary

Methods
Modifier and Type	Method and Description
`int`	`activeSegments()` Used by tests.
`void`	`add(RowMutation rm)` Add a RowMutation to the commit log.
`void`	`discardCompletedSegments(java.util.UUID cfId, ReplayPosition context)` Modifies the per-CF dirty cursors of any commit log segments for the column family according to the position given.
`java.util.List<java.lang.String>`	`getActiveSegmentNames()`
`java.lang.String`	`getArchiveCommand()` Command to execute to archive a commitlog segment.
`java.util.List<java.lang.String>`	`getArchivingSegmentNames()`
`long`	`getCompletedTasks()` Get the number of completed tasks
`java.util.concurrent.Future<ReplayPosition>`	`getContext()`
`long`	`getPendingTasks()` Get the number of tasks waiting to be executed
`java.lang.String`	`getRestoreCommand()` Command to execute to make an archived commitlog live again
`java.lang.String`	`getRestoreDirectories()` Directory to scan the recovery files in
`long`	`getRestorePointInTime()` Restore mutations created up to and including this timestamp in GMT Format: yyyy:MM:dd HH:mm:ss (2012:04:31 20:43:12) Recovery will continue through the segment when the first client-supplied timestamp greater than this time is encountered, but only mutations less than or equal to this timestamp will be applied.
`java.lang.String`	`getRestorePrecision()` get precision of the timestamp used in the restore (MILLISECONDS, MICROSECONDS, ...) to determine if passed the restore point in time.
`long`	`getTotalCommitlogSize()` Get the current size used by all the commitlog segments.
`static boolean`	`handleCommitError(java.lang.String message, java.lang.Throwable t)`
`int`	`recover()` Perform recovery on commit logs located in the directory specified by the config file.
`int`	`recover(java.io.File... clogs)` Perform recovery on a list of commit log files.
`void`	`recover(java.lang.String path)` Perform recovery on a single commit log.
`void`	`resetUnsafe()` FOR TESTING PURPOSES.
`void`	`shutdownBlocking()` Shuts down the threads used by the commit log, blocking until completion.
`void`	`sync()` Forces a disk flush on the commit log files that need it.

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

- Field Detail
  - instance
```
public static final CommitLog instance
```
  - allocator
```
public final CommitLogAllocator allocator
```
  - archiver
```
public final CommitLogArchiver archiver
```
  - END_OF_SEGMENT_MARKER
```
public static final int END_OF_SEGMENT_MARKER
```
    See Also:
    Constant Field Values
  - END_OF_SEGMENT_MARKER_SIZE
```
public static final int END_OF_SEGMENT_MARKER_SIZE
```
    See Also:
    Constant Field Values
  - activeSegment
```
public volatile CommitLogSegment activeSegment
```
- Method Detail
  - resetUnsafe
```
public void resetUnsafe()
```
    FOR TESTING PURPOSES. See CommitLogAllocator.
  - recover
```
public int recover()
            throws java.io.IOException
```
    Perform recovery on commit logs located in the directory specified by the config file.
    
    Returns:
    the number of mutations replayed
    
    Throws:
    
    java.io.IOException
  - recover
```
public int recover(java.io.File... clogs)
            throws java.io.IOException
```
    Perform recovery on a list of commit log files.
    
    Parameters:
    clogs - the list of commit log files to replay
    
    Returns:
    the number of mutations replayed
    
    Throws:
    
    java.io.IOException
  - recover
```
public void recover(java.lang.String path)
             throws java.io.IOException
```
    Perform recovery on a single commit log.
    
    Specified by:
    
    recover in interface CommitLogMBean
    
    Throws:
    
    java.io.IOException
  - getContext
```
public java.util.concurrent.Future<ReplayPosition> getContext()
```
    Returns:
    a Future representing a ReplayPosition such that when it is ready, all commitlog tasks enqueued prior to the getContext call will be complete (i.e., appended to the log)
  - activeSegments
```
public int activeSegments()
```
    Used by tests.
    
    Returns:
    the number of active segments (segments with unflushed data in them)
  - add
```
public void add(RowMutation rm)
```
    Add a RowMutation to the commit log.
    
    Parameters:
    rm - the RowMutation to add to the log
  - discardCompletedSegments
```
public void discardCompletedSegments(java.util.UUID cfId,
                            ReplayPosition context)
```
    Modifies the per-CF dirty cursors of any commit log segments for the column family according to the position given. Discards any commit log segments that are no longer used.
    
    Parameters:
    cfId - the column family ID that was flushed
    context - the replay position of the flush
  - sync
```
public void sync()
```
    Forces a disk flush on the commit log files that need it.
  - getCompletedTasks
```
public long getCompletedTasks()
```
    Description copied from interface: CommitLogMBean
    
    Get the number of completed tasks
    
    Specified by:
    
    getCompletedTasks in interface CommitLogMBean
    
    Returns:
    the number of tasks completed by the commit log executor
    See Also:
    CommitLogMetrics.completedTasks
  - getPendingTasks
```
public long getPendingTasks()
```
    Description copied from interface: CommitLogMBean
    
    Get the number of tasks waiting to be executed
    
    Specified by:
    
    getPendingTasks in interface CommitLogMBean
    
    Returns:
    the depth of pending commit log executor queue
    See Also:
    CommitLogMetrics.pendingTasks
  - getTotalCommitlogSize
```
public long getTotalCommitlogSize()
```
    Description copied from interface: CommitLogMBean
    
    Get the current size used by all the commitlog segments.
    
    Specified by:
    
    getTotalCommitlogSize in interface CommitLogMBean
    
    Returns:
    the total size occupied by commitlo segments expressed in bytes. (used by MBean)
    See Also:
    CommitLogMetrics.totalCommitLogSize
  - getArchiveCommand
```
public java.lang.String getArchiveCommand()
```
    Description copied from interface: CommitLogMBean
    
    Command to execute to archive a commitlog segment. Blank to disabled.
    
    Specified by:
    
    getArchiveCommand in interface CommitLogMBean
  - getRestoreCommand
```
public java.lang.String getRestoreCommand()
```
    Description copied from interface: CommitLogMBean
    
    Command to execute to make an archived commitlog live again
    
    Specified by:
    
    getRestoreCommand in interface CommitLogMBean
  - getRestoreDirectories
```
public java.lang.String getRestoreDirectories()
```
    Description copied from interface: CommitLogMBean
    
    Directory to scan the recovery files in
    
    Specified by:
    
    getRestoreDirectories in interface CommitLogMBean
  - getRestorePointInTime
```
public long getRestorePointInTime()
```
    Description copied from interface: CommitLogMBean
    
    Restore mutations created up to and including this timestamp in GMT Format: yyyy:MM:dd HH:mm:ss (2012:04:31 20:43:12) Recovery will continue through the segment when the first client-supplied timestamp greater than this time is encountered, but only mutations less than or equal to this timestamp will be applied.
    
    Specified by:
    
    getRestorePointInTime in interface CommitLogMBean
  - getRestorePrecision
```
public java.lang.String getRestorePrecision()
```
    Description copied from interface: CommitLogMBean
    
    get precision of the timestamp used in the restore (MILLISECONDS, MICROSECONDS, ...) to determine if passed the restore point in time.
    
    Specified by:
    
    getRestorePrecision in interface CommitLogMBean
  - getActiveSegmentNames
```
public java.util.List<java.lang.String> getActiveSegmentNames()
```
    Specified by:
    
    getActiveSegmentNames in interface CommitLogMBean
    
    Returns:
    file names (not full paths) of active commit log segments (segments containing unflushed data)
  - getArchivingSegmentNames
```
public java.util.List<java.lang.String> getArchivingSegmentNames()
```
    Specified by:
    
    getArchivingSegmentNames in interface CommitLogMBean
    
    Returns:
    Files which are pending for archival attempt. Does NOT include failed archive attempts.
  - shutdownBlocking
```
public void shutdownBlocking()
                      throws java.lang.InterruptedException
```
    Shuts down the threads used by the commit log, blocking until completion.
    
    Throws:
    
    java.lang.InterruptedException
  - handleCommitError
```
public static boolean handleCommitError(java.lang.String message,
                        java.lang.Throwable t)
```

Class CommitLog

Field Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

instance

allocator

archiver

END_OF_SEGMENT_MARKER

END_OF_SEGMENT_MARKER_SIZE

activeSegment

Method Detail

resetUnsafe

recover

recover

recover

getContext

activeSegments

add

discardCompletedSegments

sync

getCompletedTasks

getPendingTasks

getTotalCommitlogSize

getArchiveCommand

getRestoreCommand

getRestoreDirectories

getRestorePointInTime

getRestorePrecision

getActiveSegmentNames

getArchivingSegmentNames

shutdownBlocking

handleCommitError