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-orientechnologies.com)

Field Summary

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

closed, lastCheckpoint, syncObject

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	addFullCheckpointListener(OFullCheckpointRequestListener listener)
void	addLowDiskSpaceListener(OLowDiskSpaceListener listener)
boolean	appendNewSegment() Adds new segment so all sequent log entries will be added to this new segment.
OLogSequenceNumber	begin()
void	close()
void	close(boolean flush)
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()
void	delete(boolean flush)
OLogSequenceNumber	end()
void	flush()
OLogSequenceNumber	getFlushedLsn()
OLogSequenceNumber	getOldestTxLsn()
long	getPreferredSegmentCount()
OLogSequenceNumber	log(OWALRecord record)
OLogSequenceNumber	logAtomicOperationEndRecord(OOperationUnitId operationUnitId, boolean rollback, OLogSequenceNumber startLsn, Map<String,OAtomicOperationMetadata<?>> atomicOperationMetadata)
OLogSequenceNumber	logAtomicOperationStartRecord(boolean isRollbackSupported, OOperationUnitId unitId)
void	moveLsnAfter(OLogSequenceNumber lsn) Next LSN generated by WAL will be bigger than passed in value.
OLogSequenceNumber	next(OLogSequenceNumber lsn)
File[]	nonActiveSegments(long fromSegment)
OWALRecord	read(OLogSequenceNumber lsn)
void	removeCutTillLimit(OLogSequenceNumber lsn) Removes LSN after which WAL log should be preserved.
void	removeFullCheckpointListener(OFullCheckpointRequestListener listener)
void	removeLowDiskSpaceListener(OLowDiskSpaceListener listener)
void	truncate()

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

checkForClose, 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()
                         throws IOException

Throws:

IOException

end

public OLogSequenceNumber end()

getOldestTxLsn

public OLogSequenceNumber getOldestTxLsn()

flush

public void flush()

logAtomicOperationStartRecord

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

Throws:

IOException

logAtomicOperationEndRecord

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

Throws:

IOException

log

public OLogSequenceNumber log(OWALRecord record)
                       throws IOException

Throws:

IOException

truncate

public void truncate()
              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

delete

public void delete(boolean flush)
            throws IOException

Throws:

IOException

read

public OWALRecord read(OLogSequenceNumber lsn)
                throws IOException

Throws:

IOException

next

public OLogSequenceNumber next(OLogSequenceNumber lsn)
                        throws IOException

Throws:

IOException

getFlushedLsn

public OLogSequenceNumber getFlushedLsn()

cutTill

public boolean cutTill(OLogSequenceNumber lsn)

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.

addFullCheckpointListener

public void addFullCheckpointListener(OFullCheckpointRequestListener listener)

removeFullCheckpointListener

public void removeFullCheckpointListener(OFullCheckpointRequestListener 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)

activeSegment

public long activeSegment()

getPreferredSegmentCount

public long getPreferredSegmentCount()

Returns:

preferred segment count this WAL instance tries to keep under. In fact, there may be less segments or more segments in this WAL instance than the returned count, but the returned count is preferred by this WAL instance.

addLowDiskSpaceListener

public void addLowDiskSpaceListener(OLowDiskSpaceListener listener)

removeLowDiskSpaceListener

public void removeLowDiskSpaceListener(OLowDiskSpaceListener listener)

appendNewSegment

public boolean appendNewSegment()

Description copied from interface: OWriteAheadLog

Adds new segment so all sequent 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.