Package org.apache.zookeeper.server

Class ZKDatabase

  • public class ZKDatabase
extends java.lang.Object
    This class maintains the in memory database of zookeeper server states that includes the sessions, datatree and the committed logs. It is booted up after reading the logs and snapshots from the disk.

    • Constructor Summary

      Constructors 
      Constructor Description
      ZKDatabase​(FileTxnSnapLog snapLog)
      the filetxnsnaplog that this zk database maps to.

    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      java.util.List<ACL> aclForNode​(DataNode n)  
      void addCommittedProposal​(Request request)
      maintains a list of last committedLog or so committed requests.
      boolean append​(Request si)
      append to the underlying transaction log
      void clear()
      clear the zkdatabase.
      void close()
      close this database.
      void commit()
      commit to the underlying transaction log
      void deserializeSnapshot​(org.apache.jute.InputArchive ia)
      deserialize a snapshot from an input archive
      void dumpEphemerals​(java.io.PrintWriter pwriter)
      write a text dump of all the ephemerals in the datatree
      long fastForwardDataBase()
      Fast forward the database adding transactions from the committed log into memory.
      java.util.List<ACL> getACL​(java.lang.String path, Stat stat)
      get acl for a path
      int getAclSize()
      get the acl size of the datatree
      java.util.List<java.lang.String> getChildren​(java.lang.String path, Stat stat, Watcher watcher)
      get children list for this path
      java.util.LinkedList<Leader.Proposal> getCommittedLog()  
      byte[] getData​(java.lang.String path, Stat stat, Watcher watcher)
      get data and stat for a path
      DataTree getDataTree()
      the datatree for this zkdatabase
      long getDataTreeLastProcessedZxid()
      get the last processed zxid from a datatree
      java.util.HashSet<java.lang.String> getEphemerals​(long sessionId)
      the paths for ephemeral session id
      java.util.concurrent.locks.ReentrantReadWriteLock getLogLock()
      Get the lock that controls the committedLog.
      long getmaxCommittedLog()
      the committed log for this zk database
      long getminCommittedLog()
      the minimum committed transaction log available in memory
      DataNode getNode​(java.lang.String path)
      get the datanode for this path
      int getNodeCount()
      the node count of the datatree
      java.util.Collection<java.lang.Long> getSessions()
      return the sessions in the datatree
      java.util.concurrent.ConcurrentHashMap<java.lang.Long,​java.lang.Integer> getSessionWithTimeOuts()
      get sessions with timeouts
      boolean isInitialized()
      checks to see if the zk database has been initialized or not.
      boolean isSpecialPath​(java.lang.String path)
      check if the path is special or not
      void killSession​(long sessionId, long zxid)
      kill a given session in the datatree
      long loadDataBase()
      load the database from the disk onto memory and also add the transactions to the committedlog in memory.
      DataTree.ProcessTxnResult processTxn​(TxnHeader hdr, org.apache.jute.Record txn)
      the process txn on the data
      void removeCnxn​(ServerCnxn cnxn)
      remove a cnxn from the datatree
      void rollLog()
      roll the underlying log
      void serializeSnapshot​(org.apache.jute.OutputArchive oa)
      serialize the snapshot
      void setDataTreeInit​(boolean b)
      set the datatree initialized or not
      void setlastProcessedZxid​(long zxid)
      the last processed zxid in the datatree
      void setWatches​(long relativeZxid, java.util.List<java.lang.String> dataWatches, java.util.List<java.lang.String> existWatches, java.util.List<java.lang.String> childWatches, Watcher watcher)
      set watches on the datatree
      Stat statNode​(java.lang.String path, ServerCnxn serverCnxn)
      stat the path
      boolean truncateLog​(long zxid)
      Truncate the ZKDatabase to the specified zxid

      • Methods inherited from class java.lang.Object

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

    • Field Detail

      • dataTree

        protected DataTree dataTree
        make sure on a clear you take care of all these members.

      • sessionsWithTimeouts

        protected java.util.concurrent.ConcurrentHashMap<java.lang.Long,​java.lang.Integer> sessionsWithTimeouts

      • minCommittedLog

        protected long minCommittedLog

      • maxCommittedLog

        protected long maxCommittedLog

      • commitLogBuffer

        protected static int commitLogBuffer

      • committedLog

        protected java.util.LinkedList<Leader.Proposal> committedLog

      • logLock

        protected java.util.concurrent.locks.ReentrantReadWriteLock logLock

    • Constructor Detail

      • ZKDatabase

        public ZKDatabase​(FileTxnSnapLog snapLog)
        the filetxnsnaplog that this zk database maps to. There is a one to one relationship between a filetxnsnaplog and zkdatabase.
        Parameters:
        snapLog - the FileTxnSnapLog mapping this zkdatabase

    • Method Detail

      • isInitialized

        public boolean isInitialized()
        checks to see if the zk database has been initialized or not.
        Returns:
        true if zk database is initialized and false if not

      • clear

        public void clear()
        clear the zkdatabase. Note to developers - be careful to see that the clear method does clear out all the data structures in zkdatabase.

      • getDataTree

        public DataTree getDataTree()
        the datatree for this zkdatabase
        Returns:
        the datatree for this zkdatabase

      • getmaxCommittedLog

        public long getmaxCommittedLog()
        the committed log for this zk database
        Returns:
        the committed log for this zkdatabase

      • getminCommittedLog

        public long getminCommittedLog()
        the minimum committed transaction log available in memory
        Returns:
        the minimum committed transaction log available in memory

      • getLogLock

        public java.util.concurrent.locks.ReentrantReadWriteLock getLogLock()
        Get the lock that controls the committedLog. If you want to get the pointer to the committedLog, you need to use this lock to acquire a read lock before calling getCommittedLog()
        Returns:
        the lock that controls the committed log

      • getCommittedLog

        public java.util.LinkedList<Leader.Proposal> getCommittedLog()

      • getDataTreeLastProcessedZxid

        public long getDataTreeLastProcessedZxid()
        get the last processed zxid from a datatree
        Returns:
        the last processed zxid of a datatree

      • setDataTreeInit

        public void setDataTreeInit​(boolean b)
        set the datatree initialized or not
        Parameters:
        b - set the datatree initialized to b

      • getSessions

        public java.util.Collection<java.lang.Long> getSessions()
        return the sessions in the datatree
        Returns:
        the data tree sessions

      • getSessionWithTimeOuts

        public java.util.concurrent.ConcurrentHashMap<java.lang.Long,​java.lang.Integer> getSessionWithTimeOuts()
        get sessions with timeouts
        Returns:
        the hashmap of sessions with timeouts

      • loadDataBase

        public long loadDataBase()
                  throws java.io.IOException
        load the database from the disk onto memory and also add the transactions to the committedlog in memory.
        Returns:
        the last valid zxid on disk
        Throws:
        java.io.IOException

      • fastForwardDataBase

        public long fastForwardDataBase()
                         throws java.io.IOException
        Fast forward the database adding transactions from the committed log into memory.
        Returns:
        the last valid zxid.
        Throws:
        java.io.IOException

      • addCommittedProposal

        public void addCommittedProposal​(Request request)
        maintains a list of last committedLog or so committed requests. This is used for fast follower synchronization.
        Parameters:
        request - committed request

      • aclForNode

        public java.util.List<ACL> aclForNode​(DataNode n)

      • removeCnxn

        public void removeCnxn​(ServerCnxn cnxn)
        remove a cnxn from the datatree
        Parameters:
        cnxn - the cnxn to remove from the datatree

      • killSession

        public void killSession​(long sessionId,
                        long zxid)
        kill a given session in the datatree
        Parameters:
        sessionId - the session id to be killed
        zxid - the zxid of kill session transaction

      • dumpEphemerals

        public void dumpEphemerals​(java.io.PrintWriter pwriter)
        write a text dump of all the ephemerals in the datatree
        Parameters:
        pwriter - the output to write to

      • getNodeCount

        public int getNodeCount()
        the node count of the datatree
        Returns:
        the node count of datatree

      • getEphemerals

        public java.util.HashSet<java.lang.String> getEphemerals​(long sessionId)
        the paths for ephemeral session id
        Parameters:
        sessionId - the session id for which paths match to
        Returns:
        the paths for a session id

      • setlastProcessedZxid

        public void setlastProcessedZxid​(long zxid)
        the last processed zxid in the datatree
        Parameters:
        zxid - the last processed zxid in the datatree

      • processTxn

        public DataTree.ProcessTxnResult processTxn​(TxnHeader hdr,
                                            org.apache.jute.Record txn)
        the process txn on the data
        Parameters:
        hdr - the txnheader for the txn
        txn - the transaction that needs to be processed
        Returns:
        the result of processing the transaction on this datatree/zkdatabase

      • getNode

        public DataNode getNode​(java.lang.String path)
        get the datanode for this path
        Parameters:
        path - the path to lookup
        Returns:
        the datanode for getting the path

      • setWatches

        public void setWatches​(long relativeZxid,
                       java.util.List<java.lang.String> dataWatches,
                       java.util.List<java.lang.String> existWatches,
                       java.util.List<java.lang.String> childWatches,
                       Watcher watcher)
        set watches on the datatree
        Parameters:
        relativeZxid - the relative zxid that client has seen
        dataWatches - the data watches the client wants to reset
        existWatches - the exists watches the client wants to reset
        childWatches - the child watches the client wants to reset
        watcher - the watcher function

      • getChildren

        public java.util.List<java.lang.String> getChildren​(java.lang.String path,
                                                    Stat stat,
                                                    Watcher watcher)
                                             throws KeeperException.NoNodeException
        get children list for this path
        Parameters:
        path - the path of the node
        stat - the stat of the node
        watcher - the watcher function for this path
        Returns:
        the list of children for this path
        Throws:
        KeeperException.NoNodeException

      • isSpecialPath

        public boolean isSpecialPath​(java.lang.String path)
        check if the path is special or not
        Parameters:
        path - the input path
        Returns:
        true if path is special and false if not

      • getAclSize

        public int getAclSize()
        get the acl size of the datatree
        Returns:
        the acl size of the datatree

      • truncateLog

        public boolean truncateLog​(long zxid)
                    throws java.io.IOException
        Truncate the ZKDatabase to the specified zxid
        Parameters:
        zxid - the zxid to truncate zk database to
        Returns:
        true if the truncate is successful and false if not
        Throws:
        java.io.IOException

      • deserializeSnapshot

        public void deserializeSnapshot​(org.apache.jute.InputArchive ia)
                         throws java.io.IOException
        deserialize a snapshot from an input archive
        Parameters:
        ia - the input archive you want to deserialize from
        Throws:
        java.io.IOException

      • serializeSnapshot

        public void serializeSnapshot​(org.apache.jute.OutputArchive oa)
                       throws java.io.IOException,
                              java.lang.InterruptedException
        serialize the snapshot
        Parameters:
        oa - the output archive to which the snapshot needs to be serialized
        Throws:
        java.io.IOException
        java.lang.InterruptedException

      • append

        public boolean append​(Request si)
               throws java.io.IOException
        append to the underlying transaction log
        Parameters:
        si - the request to append
        Returns:
        true if the append was succesfull and false if not
        Throws:
        java.io.IOException

      • rollLog

        public void rollLog()
             throws java.io.IOException
        roll the underlying log
        Throws:
        java.io.IOException

      • commit

        public void commit()
            throws java.io.IOException
        commit to the underlying transaction log
        Throws:
        java.io.IOException

      • close

        public void close()
           throws java.io.IOException
        close this database. free the resources
        Throws:
        java.io.IOException