Class FileTxnSnapLog


  • public class FileTxnSnapLog
    extends Object
    This is a helper class above the implementations of txnlog and snapshot classes
    • 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
      • 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)
                                       throws IOException
        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
        Throws:
        IOException
      • 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
      • getTxnLogElapsedSyncTime

        public long getTxnLogElapsedSyncTime()
        Returns:
        elapsed sync time of transaction log commit in milliseconds
      • setTotalLogSize

        public void setTotalLogSize​(long size)
      • getTotalLogSize

        public long getTotalLogSize()