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

CommitLogSegmentManager allocator

CommitLogArchiver archiver

static CommitLog instance

Fields
Modifier and Type	Field and Description
`CommitLogSegmentManager`	`allocator`
`CommitLogArchiver`	`archiver`
`static CommitLog`	`instance`

Method Summary

Methods
Modifier and Type	Method and Description
`int`	`activeSegments()` Used by tests.
`ReplayPosition`	`add(Mutation mutation)` Add a Mutation 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.
`void`	`forceRecycleAllSegments()` Flushes all dirty CFs, waiting for them to free and recycle any segments they were retaining
`void`	`forceRecycleAllSegments(java.lang.Iterable<java.util.UUID> droppedCfs)` Flushes all dirty CFs, waiting for them to free and recycle any segments they were retaining
`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
`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`	`requestExtraSync()` Preempts the CLExecutor, telling to to sync immediately
`void`	`resetUnsafe()` FOR TESTING PURPOSES.
`void`	`shutdownBlocking()` Shuts down the threads used by the commit log, blocking until completion.
`void`	`sync(boolean syncAllSegments)` 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 CommitLogSegmentManager allocator
```
  - archiver
```
public final CommitLogArchiver archiver
```
- Method Detail
  - 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 ReplayPosition getContext()
```
    Returns:
    a ReplayPosition which, if >= one returned from add(), implies add() was started (but not necessarily finished) prior to this call
  - forceRecycleAllSegments
```
public void forceRecycleAllSegments(java.lang.Iterable<java.util.UUID> droppedCfs)
```
    Flushes all dirty CFs, waiting for them to free and recycle any segments they were retaining
  - forceRecycleAllSegments
```
public void forceRecycleAllSegments()
```
    Flushes all dirty CFs, waiting for them to free and recycle any segments they were retaining
  - sync
```
public void sync(boolean syncAllSegments)
```
    Forces a disk flush on the commit log files that need it. Blocking.
  - requestExtraSync
```
public void requestExtraSync()
```
    Preempts the CLExecutor, telling to to sync immediately
  - add
```
public ReplayPosition add(Mutation mutation)
```
    Add a Mutation to the commit log.
    
    Parameters:
    mutation - the Mutation 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
  - getCompletedTasks
```
public long getCompletedTasks()
```
    Description copied from interface: CommitLogMBean
    
    Get the number of completed tasks
    
    Specified by:
    
    getCompletedTasks in interface CommitLogMBean
    
    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
    
    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 commitlog 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
  - resetUnsafe
```
public void resetUnsafe()
```
    FOR TESTING PURPOSES. See CommitLogAllocator. There is a race at the moment, even if this method is synchronized we can still create an allocation on a segment that will be closed in this method, therefore causing CommitLogSegment.Allocation.awaitDiskSync() to hang forever. This typically happens because of the mutations created by SSTableReader.GlobalTidy, that's why we wait for all deletions to complete firtst.
  - activeSegments
```
public int activeSegments()
```
    Used by tests.
    
    Returns:
    the number of active segments (segments with unflushed data in them)
  - 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

Method Detail

recover

recover

recover

getContext

forceRecycleAllSegments

forceRecycleAllSegments

sync

requestExtraSync

add

discardCompletedSegments

getCompletedTasks

getPendingTasks

getTotalCommitlogSize

getArchiveCommand

getRestoreCommand

getRestoreDirectories

getRestorePointInTime

getRestorePrecision

getActiveSegmentNames

getArchivingSegmentNames

shutdownBlocking

resetUnsafe

activeSegments

handleCommitError