org.apache.zookeeper.server.persistence

Class FileTxnSnapLog

java.lang.Object

org.apache.zookeeper.server.persistence.FileTxnSnapLog

public class FileTxnSnapLog
extends Object

This is a helper class above the implementations of txnlog and snapshot classes

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	FileTxnSnapLog.DatadirException
static class	FileTxnSnapLog.LogDirContentCheckException
static interface	FileTxnSnapLog.PlayBackListener This listener helps the external apis calling restore to gather information while the data is being restored.
static class	FileTxnSnapLog.SnapDirContentCheckException

Field Summary

Fields

Modifier and Type	Field and Description
static String	version
static int	VERSION
static String	ZOOKEEPER_DATADIR_AUTOCREATE
static String	ZOOKEEPER_DATADIR_AUTOCREATE_DEFAULT
static String	ZOOKEEPER_SNAPSHOT_TRUST_EMPTY

Constructor Summary

Constructors

Constructor and Description
FileTxnSnapLog(File dataDir, File snapDir) the constructor which takes the datadir and snapdir.

Method Summary

Modifier and Type	Method and Description
boolean	append(Request si) append the request to the transaction logs
void	close() close the transaction log files
void	commit() commit the transaction of logs
long	fastForwardFromEdits(DataTree dt, Map<Long,Integer> sessions, FileTxnSnapLog.PlayBackListener listener) This function will fast forward the server database to have the latest transactions in it.
File	findMostRecentSnapshot() the most recent snapshot in the snapshot directory
List<File>	findNRecentSnapshots(int n) the n most recent snapshots
List<File>	findNValidSnapshots(int n) the n recent valid snapshots
File	getDataDir() get the datadir used by this filetxn snap log
long	getLastLoggedZxid() the last logged zxid on the transaction logs
SnapshotInfo	getLastSnapshotInfo() get information of the last saved/restored snapshot
File	getSnapDir() get the snap dir used by this filetxn snap log
File[]	getSnapshotLogs(long zxid) get the snapshot logs which may contain transactions newer than the given zxid.
long	getTotalLogSize()
long	getTxnLogElapsedSyncTime()
void	processTransaction(TxnHeader hdr, DataTree dt, Map<Long,Integer> sessions, Record txn) process the transaction on the datatree
TxnLog.TxnIterator	readTxnLog(long zxid) Get TxnIterator for iterating through txnlog starting at a given zxid
TxnLog.TxnIterator	readTxnLog(long zxid, boolean fastForward) Get TxnIterator for iterating through txnlog starting at a given zxid
long	restore(DataTree dt, Map<Long,Integer> sessions, FileTxnSnapLog.PlayBackListener listener) this function restores the server database after reading from the snapshots and transaction logs
void	rollLog() roll the transaction logs
void	save(DataTree dataTree, ConcurrentHashMap<Long,Integer> sessionsWithTimeouts, boolean syncSnap) save the datatree and the sessions into a snapshot
void	setServerStats(ServerStats serverStats)
void	setTotalLogSize(long size)
boolean	shouldForceWriteInitialSnapshotAfterLeaderElection() whether to force the write of an initial snapshot after a leader election, to address ZOOKEEPER-3781 after upgrading from Zookeeper 3.4.x.
boolean	truncateLog(long zxid) truncate the transaction logs the zxid specified

Methods inherited from class java.lang.Object

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

Field Detail

VERSION

public static final int VERSION

See Also:

Constant Field Values

version

public static final String version

See Also:

Constant Field Values

ZOOKEEPER_DATADIR_AUTOCREATE

public static final String ZOOKEEPER_DATADIR_AUTOCREATE

See Also:

Constant Field Values

ZOOKEEPER_DATADIR_AUTOCREATE_DEFAULT

public static final String ZOOKEEPER_DATADIR_AUTOCREATE_DEFAULT

See Also:

Constant Field Values

ZOOKEEPER_SNAPSHOT_TRUST_EMPTY

public static final String ZOOKEEPER_SNAPSHOT_TRUST_EMPTY

See Also:

Constant Field Values

Constructor Detail

FileTxnSnapLog

public FileTxnSnapLog(File dataDir,
                      File snapDir)
               throws IOException

the constructor which takes the datadir and snapdir.

Parameters:

dataDir - the transaction directory

snapDir - the snapshot directory

Throws:

IOException

Method Detail

setServerStats

public void setServerStats(ServerStats serverStats)

getDataDir

public File getDataDir()

get the datadir used by this filetxn snap log

Returns:

the data dir

getSnapDir

public File getSnapDir()

get the snap dir used by this filetxn snap log

Returns:

the snap dir

getLastSnapshotInfo

public SnapshotInfo getLastSnapshotInfo()

get information of the last saved/restored snapshot

Returns:

info of last snapshot

shouldForceWriteInitialSnapshotAfterLeaderElection

public boolean shouldForceWriteInitialSnapshotAfterLeaderElection()

whether to force the write of an initial snapshot after a leader election, to address ZOOKEEPER-3781 after upgrading from Zookeeper 3.4.x.

Returns:

true if an initial snapshot should be written even if not otherwise required, false otherwise.

restore

public long restore(DataTree dt,
                    Map<Long,Integer> sessions,
                    FileTxnSnapLog.PlayBackListener listener)
             throws IOException

this function restores the server database after reading from the snapshots and transaction logs

Parameters:

dt - the datatree to be restored

sessions - the sessions to be restored

listener - the playback listener to run on the database restoration

Returns:

the highest zxid restored

Throws:

IOException

fastForwardFromEdits

public long fastForwardFromEdits(DataTree dt,
                                 Map<Long,Integer> sessions,
                                 FileTxnSnapLog.PlayBackListener listener)
                          throws IOException

This function will fast forward the server database to have the latest transactions in it. This is the same as restore, but only reads from the transaction logs and not restores from a snapshot.

Parameters:

dt - the datatree to write transactions to.

sessions - the sessions to be restored.

listener - the playback listener to run on the database transactions.

Returns:

the highest zxid restored.

Throws:

IOException

readTxnLog

public TxnLog.TxnIterator readTxnLog(long zxid)
                              throws IOException

Get TxnIterator for iterating through txnlog starting at a given zxid

Parameters:

zxid - starting zxid

Returns:

TxnIterator

Throws:

IOException

readTxnLog

public TxnLog.TxnIterator readTxnLog(long zxid,
                                     boolean fastForward)
                              throws IOException

Get TxnIterator for iterating through txnlog starting at a given zxid

Parameters:

zxid - starting zxid

fastForward - true if the iterator should be fast forwarded to point to the txn of a given zxid, else the iterator will point to the starting txn of a txnlog that may contain txn of a given zxid

Returns:

TxnIterator

Throws:

IOException

processTransaction

public void processTransaction(TxnHeader hdr,
                               DataTree dt,
                               Map<Long,Integer> sessions,
                               Record txn)
                        throws KeeperException.NoNodeException

process the transaction on the datatree

Parameters:

hdr - the hdr of the transaction

dt - the datatree to apply transaction to

sessions - the sessions to be restored

txn - the transaction to be applied

Throws:

KeeperException.NoNodeException

getLastLoggedZxid

public long getLastLoggedZxid()

the last logged zxid on the transaction logs

Returns:

the last logged zxid

save

public void save(DataTree dataTree,
                 ConcurrentHashMap<Long,Integer> sessionsWithTimeouts,
                 boolean syncSnap)
          throws IOException

save the datatree and the sessions into a snapshot

Parameters:

dataTree - the datatree to be serialized onto disk

sessionsWithTimeouts - the session timeouts to be serialized onto disk

syncSnap - sync the snapshot immediately after write

Throws:

IOException

truncateLog

public boolean truncateLog(long zxid)

truncate the transaction logs the zxid specified

Parameters:

zxid - the zxid to truncate the logs to

Returns:

true if able to truncate the log, false if not

Throws:

IOException

findMostRecentSnapshot

public File findMostRecentSnapshot()
                            throws IOException

the most recent snapshot in the snapshot directory

Returns:

the file that contains the most recent snapshot

Throws:

IOException

findNRecentSnapshots

public List<File> findNRecentSnapshots(int n)
                                throws IOException

the n most recent snapshots

Parameters:

n - the number of recent snapshots

Returns:

the list of n most recent snapshots, with the most recent in front

Throws:

IOException

findNValidSnapshots

public List<File> findNValidSnapshots(int n)

the n recent valid snapshots

Parameters:

n - the number of recent valid snapshots

Returns:

the list of n recent valid snapshots, with the most recent in front

getSnapshotLogs

public File[] getSnapshotLogs(long zxid)

get the snapshot logs which may contain transactions newer than the given zxid. This includes logs with starting zxid greater than given zxid, as well as the newest transaction log with starting zxid less than given zxid. The latter log file may contain transactions beyond given zxid.

Parameters:

zxid - the zxid that contains logs greater than zxid

Returns:

the snapshot logs which may contain transactions newer than the given zxid

append

public boolean append(Request si)
               throws IOException

append the request to the transaction logs

Parameters:

si - the request to be appended

Returns:

true iff something appended, otw false

Throws:

IOException

commit

public void commit()
            throws IOException

commit the transaction of logs

Throws:

IOException

getTxnLogElapsedSyncTime

public long getTxnLogElapsedSyncTime()

Returns:

elapsed sync time of transaction log commit in milliseconds

rollLog

public void rollLog()
             throws IOException

roll the transaction logs

Throws:

IOException

close

public void close()
           throws IOException

close the transaction log files

Throws:

IOException

setTotalLogSize

public void setTotalLogSize(long size)

getTotalLogSize

public long getTotalLogSize()