com.orientechnologies.orient.core.storage.impl.local.paginated.wal

Class OMemoryWriteAheadLog

java.lang.Object

com.orientechnologies.orient.core.storage.impl.local.paginated.wal.OAbstractWriteAheadLog

com.orientechnologies.orient.core.storage.impl.local.paginated.wal.OMemoryWriteAheadLog

All Implemented Interfaces:

OWriteAheadLog

public class OMemoryWriteAheadLog
extends OAbstractWriteAheadLog

Since:

6/25/14

Author:

Andrey Lomakin (a.lomakin-at-orientdb.com)

Field Summary

Fields inherited from interface com.orientechnologies.orient.core.storage.impl.local.paginated.wal.OWriteAheadLog

MASTER_RECORD_EXTENSION, WAL_SEGMENT_EXTENSION

Constructor Summary

Constructors

Constructor and Description
OMemoryWriteAheadLog()

Method Summary

Modifier and Type	Method and Description
long	activeSegment()
void	addCutTillLimit(OLogSequenceNumber lsn) Adds LSN after which WAL log should be preserved.
void	addEventAt(OLogSequenceNumber lsn, Runnable event) Adds the event to fire when this write ahead log instances reaches the given LSN.
void	addFullCheckpointListener(OCheckpointRequestListener listener)
void	addLowDiskSpaceListener(OLowDiskSpaceListener listener)
boolean	appendNewSegment() Adds new segment so all subsequent log entries will be added to this new segment.
OLogSequenceNumber	begin()
OLogSequenceNumber	begin(long segmentId)
void	close()
void	close(boolean flush)
boolean	cutAllSegmentsSmallerThan(long segmentId)
boolean	cutTill(OLogSequenceNumber lsn) Cut WAL content till passed in value of LSN at maximum in many cases smaller portion of WAL may be cut.
void	delete()
OLogSequenceNumber	end()
void	flush()
OLogSequenceNumber	getFlushedLsn()
OLogSequenceNumber	log(OWriteableWALRecord record)
OLogSequenceNumber	logAtomicOperationEndRecord(long operationUnitId, boolean rollback, OLogSequenceNumber startLsn, Map<String,OAtomicOperationMetadata<?>> atomicOperationMetadata)
OLogSequenceNumber	logAtomicOperationStartRecord(boolean isRollbackSupported, long unitId)
void	moveLsnAfter(OLogSequenceNumber lsn) Next LSN generated by WAL will be bigger than passed in value.
List<OWriteableWALRecord>	next(OLogSequenceNumber lsn, int limit)
long[]	nonActiveSegments()
File[]	nonActiveSegments(long fromSegment)
List<OWriteableWALRecord>	read(OLogSequenceNumber lsn, int limit)
void	removeCutTillLimit(OLogSequenceNumber lsn) Removes LSN after which WAL log should be preserved.
void	removeFullCheckpointListener(OCheckpointRequestListener listener)
void	removeLowDiskSpaceListener(OLowDiskSpaceListener listener)

Methods inherited from class com.orientechnologies.orient.core.storage.impl.local.paginated.wal.OAbstractWriteAheadLog

getLastCheckpoint, logFullCheckpointEnd, logFullCheckpointStart, logFuzzyCheckPointEnd, logFuzzyCheckPointStart

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

OMemoryWriteAheadLog

public OMemoryWriteAheadLog()

Method Detail

begin

public OLogSequenceNumber begin()

end

public OLogSequenceNumber end()

flush

public void flush()

logAtomicOperationStartRecord

public OLogSequenceNumber logAtomicOperationStartRecord(boolean isRollbackSupported,
                                                        long unitId)
                                                 throws IOException

Throws:

IOException

logAtomicOperationEndRecord

public OLogSequenceNumber logAtomicOperationEndRecord(long operationUnitId,
                                                      boolean rollback,
                                                      OLogSequenceNumber startLsn,
                                                      Map<String,OAtomicOperationMetadata<?>> atomicOperationMetadata)
                                               throws IOException

Throws:

IOException

log

public OLogSequenceNumber log(OWriteableWALRecord record)
                       throws IOException

Throws:

IOException

close

public void close()
           throws IOException

Throws:

IOException

close

public void close(boolean flush)
           throws IOException

Throws:

IOException

delete

public void delete()
            throws IOException

Throws:

IOException

read

public List<OWriteableWALRecord> read(OLogSequenceNumber lsn,
                                      int limit)
                               throws IOException

Throws:

IOException

next

public List<OWriteableWALRecord> next(OLogSequenceNumber lsn,
                                      int limit)
                               throws IOException

Throws:

IOException

getFlushedLsn

public OLogSequenceNumber getFlushedLsn()

cutTill

public boolean cutTill(OLogSequenceNumber lsn)
                throws IOException

Description copied from interface: OWriteAheadLog

Cut WAL content till passed in value of LSN at maximum in many cases smaller portion of WAL may be cut. If value of LSN is bigger than values provided in OWriteAheadLog.addCutTillLimit(OLogSequenceNumber) then "protected" part of WAL will be preserved for sure.

Parameters:

lsn - Maximum value of LSN till WAL will be cut.

Returns:

true if some portion of WAL will be cut and false if WAL left untouched.

Throws:

IOException

addFullCheckpointListener

public void addFullCheckpointListener(OCheckpointRequestListener listener)

removeFullCheckpointListener

public void removeFullCheckpointListener(OCheckpointRequestListener listener)

moveLsnAfter

public void moveLsnAfter(OLogSequenceNumber lsn)

Description copied from interface: OWriteAheadLog

Next LSN generated by WAL will be bigger than passed in value. DO NOT REMOVE IT, USED IN ENTERPRISE STORAGE.

addCutTillLimit

public void addCutTillLimit(OLogSequenceNumber lsn)

Description copied from interface: OWriteAheadLog

Adds LSN after which WAL log should be preserved. It is possible to add many such LSNs smallest value among them will be used to limit value of LSN after which WAL may be cut.

Parameters:

lsn - LSN after which cut of the WAL is not allowed.

See Also:

OWriteAheadLog.removeCutTillLimit(OLogSequenceNumber), OWriteAheadLog.cutTill(OLogSequenceNumber)

removeCutTillLimit

public void removeCutTillLimit(OLogSequenceNumber lsn)

Description copied from interface: OWriteAheadLog

Removes LSN after which WAL log should be preserved. It is possible to add many such LSNs smallest value among them will be used to limit value of LSN after which WAL may be cut.

Parameters:

lsn - LSN after which cut of the WAL is not allowed.

See Also:

OWriteAheadLog.removeCutTillLimit(OLogSequenceNumber), OWriteAheadLog.cutTill(OLogSequenceNumber)

nonActiveSegments

public File[] nonActiveSegments(long fromSegment)

nonActiveSegments

public long[] nonActiveSegments()

activeSegment

public long activeSegment()

addLowDiskSpaceListener

public void addLowDiskSpaceListener(OLowDiskSpaceListener listener)

removeLowDiskSpaceListener

public void removeLowDiskSpaceListener(OLowDiskSpaceListener listener)

begin

public OLogSequenceNumber begin(long segmentId)

cutAllSegmentsSmallerThan

public boolean cutAllSegmentsSmallerThan(long segmentId)

addEventAt

public void addEventAt(OLogSequenceNumber lsn,
                       Runnable event)

Description copied from interface: OWriteAheadLog

Adds the event to fire when this write ahead log instances reaches the given LSN. The thread on which the event will be fired is unspecified, the event may be even fired synchronously before this method returns. Avoid running long tasks in the event handler since this may degrade the performance of this write ahead log and/or its event managing component. The exact LSN, up to which this write ahead log is actually grown, may differ from the event's LSN at the moment of invocation. But it's guarantied that the write ahead log's LSN will be larger than or equal to the event's LSN. In other words, the event invocation may be postponed, exact timings depend on implementation details of this write ahead log.

Parameters:

lsn - the LSN to fire at.

event - the event to fire.

appendNewSegment

public boolean appendNewSegment()

Description copied from interface: OWriteAheadLog

Adds new segment so all subsequent log entries will be added to this new segment. New segment can not be appended if:

1. WAL is empty
2. There last segment in WAL is empty.

Despite of the fact that WAL segment will not be appended, method call still will reach its main target, all subsequent log records will have segment number higher than previously logged records. But to inform user that segment is not added result of success of failure of this method will be returned.

Returns:

true if new segment is added, and false otherwise.