com.sleepycat.je.rep.stream

Class ReplicaSyncupReader

java.lang.Object

com.sleepycat.je.log.FileReader

com.sleepycat.je.rep.stream.VLSNReader

com.sleepycat.je.rep.stream.ReplicaSyncupReader

public class ReplicaSyncupReader
extends VLSNReader

The ReplicaSyncupReader scans the log backwards for requested log entries. The reader must track whether it has passed a checkpoint, and therefore can not used the vlsn index to skip over entries. The ReplicaSyncupReader is not thread safe, and can only be used serially. It will stop at the finishLsn, which should be set using the GlobalCBVLSN.

Nested Class Summary

Nested classes/interfaces inherited from class com.sleepycat.je.log.FileReader

FileReader.EOFException, FileReader.ReadWindow

Field Summary

Fields inherited from class com.sleepycat.je.rep.stream.VLSNReader

currentFeedRecord, currentVLSN, nReposition, nScanned, vlsnIndex

Fields inherited from class com.sleepycat.je.log.FileReader

cksumValidator, currentEntryHeader, currentEntryOffset, currentEntryPrevOffset, envImpl, eof, fileManager, forward, nextEntryOffset, startLsn, window

Constructor Summary

Constructors

Constructor and Description
ReplicaSyncupReader(EnvironmentImpl envImpl, VLSNIndex vlsnIndex, long endOfLogLsn, int readBufferSize, NameIdPair nameIdPair, VLSN startVLSN, long finishLsn, MatchpointSearchResults searchResults)

Method Summary

Methods

Modifier and Type	Method and Description
OutputWireRecord	findPrevSyncEntry() Backward scanning for finding an earlier candidate syncup matchpoint.
protected boolean	isTargetEntry() Return true for ckpt entries, for syncable entries, and if we're in specific vlsn scan mode, any replicated entry.
protected boolean	processEntry(java.nio.ByteBuffer entryBuffer) ProcessEntry does additional filtering before deciding whether to return an entry as a candidate for matching.
OutputWireRecord	scanBackwards(VLSN vlsn) Backward scanning for the replica's part in syncup.

Methods inherited from class com.sleepycat.je.rep.stream.VLSNReader

getNReposition, getNScanned, resetStats, setPosition

Methods inherited from class com.sleepycat.je.log.FileReader

entryIsReplicated, getAndResetNReads, getLastEntrySize, getLastLsn, getNRepeatIteratorReads, getNumRead, initStartingPosition, makeWindow, readNextEntry, readNextEntryAllowExceptions, resyncReader, setAlwaysValidateChecksum, setBackwardPosition, setForwardPosition, skipData, skipEntry

Methods inherited from class java.lang.Object

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

Constructor Detail

ReplicaSyncupReader

public ReplicaSyncupReader(EnvironmentImpl envImpl,
                   VLSNIndex vlsnIndex,
                   long endOfLogLsn,
                   int readBufferSize,
                   NameIdPair nameIdPair,
                   VLSN startVLSN,
                   long finishLsn,
                   MatchpointSearchResults searchResults)
                    throws java.io.IOException,
                           DatabaseException

Throws:

java.io.IOException

DatabaseException

Method Detail

scanBackwards

public OutputWireRecord scanBackwards(VLSN vlsn)
                               throws DatabaseException

Backward scanning for the replica's part in syncup.

Throws:

DatabaseException

findPrevSyncEntry

public OutputWireRecord findPrevSyncEntry()
                                   throws DatabaseException

Backward scanning for finding an earlier candidate syncup matchpoint.

Throws:

DatabaseException

isTargetEntry

protected boolean isTargetEntry()
                         throws DatabaseException

Return true for ckpt entries, for syncable entries, and if we're in specific vlsn scan mode, any replicated entry. There is an additional level of filtering in processEntry.

Overrides:

isTargetEntry in class FileReader

Returns:

true if this reader should process this entry, or just skip over it.

Throws:

DatabaseException - from subclasses.

processEntry

protected boolean processEntry(java.nio.ByteBuffer entryBuffer)

ProcessEntry does additional filtering before deciding whether to return an entry as a candidate for matching. If this is a record we are submitting as a matchpoint candidate, instantiate a WireRecord to house this log entry. If this is a non-replicated entry or a txn end that follows the candidate matchpoint, record whatever status we need to, but don't use it for comparisons. For example, suppose the log is like this:f VLSN entry 10 LN 11 commit 12 LN -- ckpt end 13 commit 14 abort And that the master only has VLSNs 1-12. The replica will suggest vlsn 14 as the first matchpoint. The feeder will counter with a suggestion of vlsn 11, since it doe not have vlsn 14. At that point, the ReplicaSyncupReader will scan backwards in the log, looking for vlsn 11. Although the reader should only return an entry when it gets to vlsn 11. the reader must process commits and ckpts that follow 11, so that they can be recorded in the searchResults, so the number of rolled back commits can be accurately reported.

Overrides:

processEntry in class VLSNReader

Parameters:

entryBuffer - contains the entry data and is positioned at the data

Returns:

true if this entry should be returned