com.persistit

Class RecoveryManager

java.lang.Object

com.persistit.RecoveryManager

All Implemented Interfaces:

RecoveryManagerMXBean

public class RecoveryManager
extends Object
implements RecoveryManagerMXBean

Manages the recovery process during Persistit startup. This method is called every time Persistit starts up, even if the previous shutdown was normal.

Phase 1:

Find the most recent valid journal file. This is the "keystone" journal file because everything will be based on its content. Read its JH (JournalHeader) record. Validate all fields in the JH.

Read the records in the keystone journal file. Included are IV, PM and TM records that provide an initial load of the pageMap, liveTransactionMap and volume/handle maps for JournalManager. Included also is a keystone CP (checkpoint) record; the presence of a CP record indicates that the IV, PM and TM records constitute a complete checkpoint of the journal to the specified timestamp. Absence of a CP before the scan terminates indicates that the journal file is not a complete snapshot, and therefore the chosen keystone journal file is not valid. In this event, restart Phase 1 using the immediate predecessor file.

During this phase, build a transaction map containing the timestamp and file address of every transaction that had not committed before the last valid checkpoint. The scan stops when recovery finds a JE "journal end" record, end-of-file or an invalid record. The presence of a valid JE record indicates a clean shutdown.

Finally, after processing the keystone journal file, validate all other required journal files. For each journal files from base address to current address, read its JH records, verify contiguity (same creation timestamp), verify that the page image and transaction records closest to the end of that journal file (if there are any) can be read. This last step is a plausibility test to make sure each required journal file is present, readable, and long enough to support recovery. This step does not test for data corruption within the journal since doing so would require a significant amount of additional I/O.

Phase 2:

Executed after the buffer pools have been loaded and the journal manager has been instantiated. This step applies every committed transaction in the transaction map and prunes the MVV values for every uncommitted transaction in the transaction map.

Transactions are applied in their commit timestamp ordering so that their affect on the recovered database is consistent with their original serial order. A checkpoint at timestamp T indicates that all pages made dirty prior to T have been written to the journal; therefore any transaction with a commit timestamp before T does not need to be reapplied because its effects are already present in the recovered B-Trees.

This class is not threadsafe; it is intended to be called only during the single-threaded recovery process.

Field Summary

Fields inherited from interface com.persistit.mxbeans.RecoveryManagerMXBean

MXBEAN_NAME

Method Summary

Modifier and Type	Method and Description
void	applyAllRecoveredTransactions(com.persistit.TransactionPlayer.TransactionPlayerListener commitListener, com.persistit.TransactionPlayer.TransactionPlayerListener rollbackListener)
void	buildRecoveryPlan()
int	getAppliedTransactionCount()
long	getBaseAddress()
long	getBlockSize()
int	getCommittedCount()
com.persistit.TransactionPlayer.TransactionPlayerListener	getDefaultCommitListener()
com.persistit.TransactionPlayer.TransactionPlayerListener	getDefaultRollbackListener()
int	getErrorCount()
long	getJournalCreatedTime()
String	getJournalFilePath()
long	getKeystoneAddress()
CheckpointManager.Checkpoint	getLastValidCheckpoint()
long	getLastValidCheckpointAddress()
long	getLastValidCheckpointTimestamp()
int	getPageMapSize()
long	getRecoveryEndedAddress()
String	getRecoveryEndedException()
int	getTransactionMapSize()
int	getUncommittedCount()
void	init(String path)
Volume	lookupVolumeHandle(int handle)
static void	main(String[] args) Read and display information about a journal.
void	setDefaultCommitListener(com.persistit.TransactionPlayer.TransactionPlayerListener listener)
void	setDefaultRollbackListener(com.persistit.TransactionPlayer.TransactionPlayerListener listener)
String	toString()

Methods inherited from class java.lang.Object

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

Method Detail

init

public void init(String path)
          throws PersistitException

Throws:

PersistitException

getJournalFilePath

public String getJournalFilePath()

Specified by:

getJournalFilePath in interface RecoveryManagerMXBean

getCommittedCount

public int getCommittedCount()

Specified by:

getCommittedCount in interface RecoveryManagerMXBean

getUncommittedCount

public int getUncommittedCount()

Specified by:

getUncommittedCount in interface RecoveryManagerMXBean

getAppliedTransactionCount

public int getAppliedTransactionCount()

Specified by:

getAppliedTransactionCount in interface RecoveryManagerMXBean

getErrorCount

public int getErrorCount()

Specified by:

getErrorCount in interface RecoveryManagerMXBean

getLastValidCheckpoint

public CheckpointManager.Checkpoint getLastValidCheckpoint()

getLastValidCheckpointTimestamp

public long getLastValidCheckpointTimestamp()

Specified by:

getLastValidCheckpointTimestamp in interface RecoveryManagerMXBean

getLastValidCheckpointAddress

public long getLastValidCheckpointAddress()

Specified by:

getLastValidCheckpointAddress in interface RecoveryManagerMXBean

getRecoveryEndedException

public String getRecoveryEndedException()

Specified by:

getRecoveryEndedException in interface RecoveryManagerMXBean

getRecoveryEndedAddress

public long getRecoveryEndedAddress()

Specified by:

getRecoveryEndedAddress in interface RecoveryManagerMXBean

getKeystoneAddress

public long getKeystoneAddress()

Specified by:

getKeystoneAddress in interface RecoveryManagerMXBean

getBaseAddress

public long getBaseAddress()

Specified by:

getBaseAddress in interface RecoveryManagerMXBean

getBlockSize

public long getBlockSize()

Specified by:

getBlockSize in interface RecoveryManagerMXBean

getJournalCreatedTime

public long getJournalCreatedTime()

Specified by:

getJournalCreatedTime in interface RecoveryManagerMXBean

getTransactionMapSize

public int getTransactionMapSize()

Specified by:

getTransactionMapSize in interface RecoveryManagerMXBean

getPageMapSize

public int getPageMapSize()

Specified by:

getPageMapSize in interface RecoveryManagerMXBean

getDefaultCommitListener

public com.persistit.TransactionPlayer.TransactionPlayerListener getDefaultCommitListener()

setDefaultCommitListener

public void setDefaultCommitListener(com.persistit.TransactionPlayer.TransactionPlayerListener listener)

getDefaultRollbackListener

public com.persistit.TransactionPlayer.TransactionPlayerListener getDefaultRollbackListener()

setDefaultRollbackListener

public void setDefaultRollbackListener(com.persistit.TransactionPlayer.TransactionPlayerListener listener)

lookupVolumeHandle

public Volume lookupVolumeHandle(int handle)

toString

public String toString()

Overrides:

toString in class Object

buildRecoveryPlan

public void buildRecoveryPlan()
                       throws PersistitIOException,
                              PersistitInterruptedException

Throws:

PersistitIOException

PersistitInterruptedException

applyAllRecoveredTransactions

public void applyAllRecoveredTransactions(com.persistit.TransactionPlayer.TransactionPlayerListener commitListener,
                                          com.persistit.TransactionPlayer.TransactionPlayerListener rollbackListener)
                                   throws TestException

Throws:

TestException

main

public static void main(String[] args)
                 throws Exception

Read and display information about a journal. Read-only - does not change any file.

Parameters:

args -

Throws:

Exception