org.apache.ignite.internal.pagemem.wal

Interface IgniteWriteAheadLogManager

All Superinterfaces:

GridCacheSharedManager, IgniteChangeGlobalStateSupport

All Known Implementing Classes:

FileWriteAheadLogManager

public interface IgniteWriteAheadLogManager
extends GridCacheSharedManager, IgniteChangeGlobalStateSupport

Method Summary

Methods

Modifier and Type	Method and Description
void	fsync(WALPointer ptr) Makes sure that all log entries written to the log up until the specified pointer are actually persisted to the underlying storage.
boolean	isAlwaysWriteFullPages()
boolean	isFullSync()
WALPointer	log(WALRecord entry) Appends the given log entry to the write-ahead log.
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
void	resumeLogging(WALPointer lastWrittenPtr) Resumes logging after start.
int	truncate(WALPointer ptr) 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, 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.

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 fsync(WALPointer) 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.

fsync

void fsync(WALPointer ptr)
           throws IgniteCheckedException,
                  StorageException

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

Parameters:

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

Throws:

IgniteCheckedException - If failed to fsync.

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 ptr)

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:

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

Returns:

Number of deleted WAL segments.

walArchiveSegments

int walArchiveSegments()

Returns:

Total number of segments in the WAL archive.

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.