org.apache.ignite.internal.pagemem.wal

Interface IgniteWriteAheadLogManager

All Superinterfaces:

GridCacheSharedManager, IgniteChangeGlobalStateSupport

All Known Implementing Classes:

FileWriteAheadLogManager, FsyncModeFileWriteAheadLogManager

public interface IgniteWriteAheadLogManager
extends GridCacheSharedManager, IgniteChangeGlobalStateSupport

Method Summary

Modifier and Type	Method and Description
void	cleanupWalDirectories() Cleanup all directories relating to WAL (e.g. work WAL dir, archive WAL dir).
boolean	disabled(int grpId) Checks WAL disabled for cache group.
void	flush(WALPointer ptr, boolean explicitFsync) Makes sure that all log entries written to the log up until the specified pointer are actually written to the underlying storage.
boolean	isAlwaysWriteFullPages()
boolean	isFullSync()
long	lastArchivedSegment()
long	lastCompactedSegment()
WALPointer	log(WALRecord entry) Appends the given log entry to the write-ahead log.
long	maxArchivedSegmentToDelete()
void	notchLastCheckpointPtr(WALPointer ptr) Notifies this about latest checkpoint pointer.
void	release(WALPointer start) Invoke this method to release WAL history since provided pointer that was previously reserved.
WALIterator	replay(WALPointer start) Invoke this method to iterate over the written log entries.
boolean	reserve(WALPointer start) Invoke this method to reserve WAL history since provided pointer and prevent it's deletion.
boolean	reserved(WALPointer ptr) Checks if WAL segment is under lock or reserved
int	reserved(WALPointer low, WALPointer high) Checks if WAL segments is under lock or reserved.
void	resumeLogging(WALPointer lastWrittenPtr) Resumes logging after start.
int	serializerVersion()
int	truncate(WALPointer low, WALPointer high) Gives a hint to WAL manager to clear entries logged before the given pointer.
int	walArchiveSegments()

Methods inherited from interface org.apache.ignite.internal.processors.cache.GridCacheSharedManager

onDisconnected, onKernalStop, onReconnected, printMemoryStats, start, stop

Methods inherited from interface org.apache.ignite.internal.processors.cluster.IgniteChangeGlobalStateSupport

onActivate, onDeActivate

Method Detail

isAlwaysWriteFullPages

boolean isAlwaysWriteFullPages()

Returns:

true If we have to always write full pages.

isFullSync

boolean isFullSync()

Returns:

true if WAL will perform fair syncs on fsync call.

serializerVersion

int serializerVersion()

Returns:

Current serializer version.

resumeLogging

void resumeLogging(WALPointer lastWrittenPtr)
            throws IgniteCheckedException

Resumes logging after start. When WAL manager is started, it will skip logging any updates until this method is called to avoid logging changes induced by the state restore procedure.

Throws:

IgniteCheckedException

log

WALPointer log(WALRecord entry)
        throws IgniteCheckedException,
               StorageException

Appends the given log entry to the write-ahead log.

Parameters:

entry - entry to log.

Returns:

WALPointer that may be passed to flush(WALPointer, boolean) method to make sure the record is written to the log.

Throws:

IgniteCheckedException - If failed to construct log entry.

StorageException - If IO error occurred while writing log entry.

flush

void flush(WALPointer ptr,
           boolean explicitFsync)
    throws IgniteCheckedException,
           StorageException

Makes sure that all log entries written to the log up until the specified pointer are actually written to the underlying storage.

Parameters:

ptr - Optional pointer to write. If null, will sync up to the latest record.

explicitFsync - If true, data will be synced to the storage device on hardware level.

Throws:

IgniteCheckedException - If failed to write.

StorageException - If IO exception occurred during the write. If an exception is thrown from this method, the WAL will be invalidated and the node will be stopped.

replay

WALIterator replay(WALPointer start)
            throws IgniteCheckedException,
                   StorageException

Invoke this method to iterate over the written log entries.

Parameters:

start - Optional WAL pointer from which to start iteration.

Returns:

Records iterator.

Throws:

IgniteException - If failed to start iteration.

StorageException - If IO error occurred while reading WAL entries.

IgniteCheckedException

reserve

boolean reserve(WALPointer start)
         throws IgniteCheckedException

Invoke this method to reserve WAL history since provided pointer and prevent it's deletion.

Parameters:

start - WAL pointer.

Throws:

IgniteException - If failed to reserve.

IgniteCheckedException

release

void release(WALPointer start)
      throws IgniteCheckedException

Invoke this method to release WAL history since provided pointer that was previously reserved.

Parameters:

start - WAL pointer.

Throws:

IgniteException - If failed to release.

IgniteCheckedException

truncate

int truncate(WALPointer low,
             WALPointer high)

Gives a hint to WAL manager to clear entries logged before the given pointer. Some entries before the the given pointer will be kept because there is a configurable WAL history size. Those entries may be used for partial partition rebalancing.

Parameters:

low - Pointer since which WAL will be truncated. If null, WAL will be truncated from the oldest segment.

high - Pointer for which it is safe to clear the log.

Returns:

Number of deleted WAL segments.

notchLastCheckpointPtr

void notchLastCheckpointPtr(WALPointer ptr)

Notifies this about latest checkpoint pointer.

Current implementations, in fact, react by keeping all WAL segments uncompacted starting from index prior to the index of ptr. Compaction implies filtering out physical records and ZIP compression.

Parameters:

ptr - Pointer for which it is safe to compact the log.

walArchiveSegments

int walArchiveSegments()

Returns:

Total number of segments in the WAL archive.

lastArchivedSegment

long lastArchivedSegment()

Returns:

Last archived segment index.

lastCompactedSegment

long lastCompactedSegment()

Returns:

Last compacted segment index.

maxArchivedSegmentToDelete

long maxArchivedSegmentToDelete()

Returns:

Max allowed index of archived segment to delete or -1 if it does not exist.

reserved

boolean reserved(WALPointer ptr)

Checks if WAL segment is under lock or reserved

Parameters:

ptr - Pointer to check.

Returns:

True if given pointer is located in reserved segment.

reserved

int reserved(WALPointer low,
             WALPointer high)

Checks if WAL segments is under lock or reserved.

Parameters:

low - Pointer since which WAL is locked or reserved. If null, checks from the oldest segment.

high - Pointer for which WAL is locked or reserved.

Returns:

Number of reserved WAL segments.

disabled

boolean disabled(int grpId)

Checks WAL disabled for cache group.

Parameters:

grpId - Group id.

cleanupWalDirectories

void cleanupWalDirectories()
                    throws IgniteCheckedException

Cleanup all directories relating to WAL (e.g. work WAL dir, archive WAL dir).

Throws:

IgniteCheckedException