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

Interface OWriteAheadLog

All Known Implementing Classes:

OAbstractWriteAheadLog, ODiskWriteAheadLog, OMemoryWriteAheadLog

public interface OWriteAheadLog

Since:

6/25/14

Author:

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

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	getLastCheckpoint()
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)
OLogSequenceNumber	logFullCheckpointEnd()
OLogSequenceNumber	logFullCheckpointStart()
OLogSequenceNumber	logFuzzyCheckPointEnd()
OLogSequenceNumber	logFuzzyCheckPointStart(OLogSequenceNumber flushedLsn)
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()

Method Detail

logFuzzyCheckPointStart

OLogSequenceNumber logFuzzyCheckPointStart(OLogSequenceNumber flushedLsn)
                                    throws IOException

Throws:

IOException

logFuzzyCheckPointEnd

OLogSequenceNumber logFuzzyCheckPointEnd()
                                  throws IOException

Throws:

IOException

logFullCheckpointStart

OLogSequenceNumber logFullCheckpointStart()
                                   throws IOException

Throws:

IOException

logFullCheckpointEnd

OLogSequenceNumber logFullCheckpointEnd()
                                 throws IOException

Throws:

IOException

getLastCheckpoint

OLogSequenceNumber getLastCheckpoint()

begin

OLogSequenceNumber begin()
                  throws IOException

Throws:

IOException

end

OLogSequenceNumber end()

flush

void flush()

logAtomicOperationStartRecord

OLogSequenceNumber logAtomicOperationStartRecord(boolean isRollbackSupported,
                                                 OOperationUnitId unitId)
                                          throws IOException

Throws:

IOException

logAtomicOperationEndRecord

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

Throws:

IOException

log

OLogSequenceNumber log(OWALRecord record)
                throws IOException

Throws:

IOException

getOldestTxLsn

OLogSequenceNumber getOldestTxLsn()

truncate

void truncate()
       throws IOException

Throws:

IOException

close

void close()
    throws IOException

Throws:

IOException

close

void close(boolean flush)
    throws IOException

Throws:

IOException

delete

void delete()
     throws IOException

Throws:

IOException

delete

void delete(boolean flush)
     throws IOException

Throws:

IOException

read

OWALRecord read(OLogSequenceNumber lsn)
         throws IOException

Throws:

IOException

next

OLogSequenceNumber next(OLogSequenceNumber lsn)
                 throws IOException

Throws:

IOException

getFlushedLsn

OLogSequenceNumber getFlushedLsn()

cutTill

boolean cutTill(OLogSequenceNumber lsn)
         throws IOException

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 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

void addFullCheckpointListener(OFullCheckpointRequestListener listener)

removeFullCheckpointListener

void removeFullCheckpointListener(OFullCheckpointRequestListener listener)

moveLsnAfter

void moveLsnAfter(OLogSequenceNumber lsn)
           throws IOException

Next LSN generated by WAL will be bigger than passed in value.

DO NOT REMOVE IT, USED IN ENTERPRISE STORAGE.

Throws:

IOException

addCutTillLimit

void addCutTillLimit(OLogSequenceNumber lsn)

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:

removeCutTillLimit(OLogSequenceNumber), cutTill(OLogSequenceNumber)

removeCutTillLimit

void removeCutTillLimit(OLogSequenceNumber lsn)

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:

removeCutTillLimit(OLogSequenceNumber), cutTill(OLogSequenceNumber)

nonActiveSegments

File[] nonActiveSegments(long fromSegment)

activeSegment

long activeSegment()

getPreferredSegmentCount

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

void addLowDiskSpaceListener(OLowDiskSpaceListener listener)

removeLowDiskSpaceListener

void removeLowDiskSpaceListener(OLowDiskSpaceListener listener)

appendNewSegment

boolean appendNewSegment()

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.