src/org/objectweb/cjdbc/controller/requestmanager/distributed/DistributedRequestManager.java

説明を見る。

package org.objectweb.cjdbc.controller.requestmanager.distributed;

import java.sql.SQLException;
import java.util.ArrayList;
import java.util.Vector;

import org.jgroups.blocks.GroupRequest;
import org.objectweb.cjdbc.common.exceptions.VirtualDatabaseException;
import org.objectweb.cjdbc.common.i18n.Translate;
import org.objectweb.cjdbc.common.log.Trace;
import org.objectweb.cjdbc.common.sql.AbstractRequest;
import org.objectweb.cjdbc.common.sql.AbstractWriteRequest;
import org.objectweb.cjdbc.common.sql.StoredProcedure;
import org.objectweb.cjdbc.controller.backend.DatabaseBackend;
import org.objectweb.cjdbc.controller.cache.result.AbstractResultCache;
import org.objectweb.cjdbc.controller.loadbalancer.AbstractLoadBalancer;
import org.objectweb.cjdbc.controller.recoverylog.AbstractRecoveryLog;
import org.objectweb.cjdbc.controller.requestmanager.RequestManager;
import org.objectweb.cjdbc.controller.requestmanager.TransactionMarkerMetaData;
import org.objectweb.cjdbc.controller.scheduler.AbstractScheduler;
import org.objectweb.cjdbc.controller.virtualdatabase.ControllerResultSet;
import org.objectweb.cjdbc.controller.virtualdatabase.DistributedVirtualDatabase;
import org.objectweb.cjdbc.controller.virtualdatabase.VirtualDatabase;
import org.objectweb.cjdbc.controller.virtualdatabase.protocol.CJDBCGroupMessage;
import org.objectweb.cjdbc.controller.virtualdatabase.protocol.EnableBackend;

public abstract class DistributedRequestManager extends RequestManager
{
  protected DistributedVirtualDatabase dvdb;
  private Vector                       failedOnAllBackends;
  private long                         controllerId;
  private ArrayList                    writeTransactions;

  public DistributedRequestManager(DistributedVirtualDatabase vdb,
      AbstractScheduler scheduler, AbstractResultCache cache,
      AbstractLoadBalancer loadBalancer, AbstractRecoveryLog recoveryLog,
      long beginTimeout, long commitTimeout, long rollbackTimeout)
      throws SQLException
  {
    super(vdb, scheduler, cache, loadBalancer, recoveryLog, beginTimeout,
        commitTimeout, rollbackTimeout);
    dvdb = vdb;
    failedOnAllBackends = new Vector();
    writeTransactions = new ArrayList();
  }

  public Trace getLogger()
  {
    return logger;
  }

  public VirtualDatabase getVirtualDatabase()
  {
    return dvdb;
  }

  //
  // Database Backends management
  //

  public void enableBackend(DatabaseBackend db) throws SQLException
  {
    int size = dvdb.getAllMemberButUs().size();
    if (size > 0)
    {
      logger.debug(Translate
          .get("virtualdatabase.distributed.enable.backend.check"));

      // Notify other controllers that we enable this backend.
      // No answer is expected.
      dvdb.getDispatcher().castMessage(dvdb.getAllMemberButUs(),
          CJDBCGroupMessage.getMessage(new EnableBackend(db)),
          GroupRequest.GET_NONE, CJDBCGroupMessage.defaultCastTimeOut);
    }

    loadBalancer.enableBackend(db, true);
    vdb.logger.info("Database backend " + db.getName() + " enabled");
  }

  public void addFailedOnAllBackends(AbstractRequest request)
  {
    failedOnAllBackends.add(request);
  }

  public void completeFailedOnAllBackends(AbstractRequest request,
      boolean success)
  {
    if (!failedOnAllBackends.remove(request))
    {
      logger.warn("Unable to find request "
          + request.getSQLShortForm(dvdb.getSQLShortFormLength())
          + " in list of requests that failed on all backends.");
      return;
    }
    if (success)
    { //We have to invalidate all backends
      logger
          .error("Request "
              + request.getSQLShortForm(dvdb.getSQLShortFormLength())
              + " failed on all local backends but succeeded on other controllers. Disabling all local backends.");
      try
      {
        dvdb.disableAllBackend();
      }
      catch (VirtualDatabaseException e)
      {
        logger.error("An error occured while disabling all backends", e);
      }
    }
  }

  //
  // Transaction management
  //

  public void setControllerId(int id)
  {
    if (id > 0xffff)
    {
      String msg = "Out of range controller id (" + id + ")";
      logger.error(msg);
      throw new RuntimeException(msg);
    }
    this.controllerId = (0x000000000000ffff & id) << 12;
  }

  public long begin(String login) throws SQLException
  {
    try
    {
      TransactionMarkerMetaData tm = new TransactionMarkerMetaData(0,
          beginTimeout, login);

      // Wait for the scheduler to give us the authorization to execute
      long tid = scheduler.begin(tm);
      // 2 first bytes are used for controller id
      // 6 right-most bytes are used for transaction id
      tid = tid & 0x0000ffffffffffffL;
      tid = tid | controllerId;
      tm.setTransactionId(tid);

      if (logger.isDebugEnabled())
        logger.debug(Translate.get("transaction.begin", String.valueOf(tid)));

      try
      {
        // Send to load balancer
        loadBalancer.begin(tm);

        // Log the begin
        if (recoveryLog != null)
        {
          recoveryLog.begin(tm);
        }
      }
      catch (SQLException e)
      {
        throw e;
      }
      finally
      {
        // Notify scheduler for completion in any case
        scheduler.beginCompleted(tid);
      }

      tidLoginTable.put(new Long(tid), tm);
      return tid;
    }
    catch (RuntimeException e)
    {
      logger.fatal(Translate.get(
          "fatal.runtime.exception.requestmanager.begin", e));
      throw new SQLException(e.getMessage());
    }
  }

  public void commit(long transactionId) throws SQLException
  {
    Long lTid = new Long(transactionId);
    boolean isAWriteTransaction;
    synchronized (writeTransactions)
    {
      isAWriteTransaction = writeTransactions.remove(lTid);
    }
    if (isAWriteTransaction)
      distributedCommit(transactionId);
    else
      // read-only transaction, it is local
      super.commit(transactionId);
  }

  public void rollback(long transactionId) throws SQLException
  {
    Long lTid = new Long(transactionId);
    boolean isAWriteTransaction;
    synchronized (writeTransactions)
    {
      isAWriteTransaction = writeTransactions.remove(lTid);
    }
    if (isAWriteTransaction)
      distributedRollback(transactionId);
    else
      // read-only transaction, it is local
      super.rollback(transactionId);
  }

  public void scheduleExecWriteRequest(AbstractWriteRequest request)
      throws SQLException
  {
    lazyTransactionStart(request);
    super.scheduleExecWriteRequest(request);
  }

  public void lazyTransactionStart(AbstractRequest request) throws SQLException
  {
    // Check if this is a remotely started transaction that we need to lazyly
    // start locally
    if (!request.isAutoCommit())
    {
      long tid = request.getTransactionId();
      if ((tid & 0x0000ffffffffffffL) != controllerId)
      { // Remote transaction, check that it is started
        if (!tidLoginTable.containsKey(new Long(tid)))
        { // Begin this transaction
          try
          {
            TransactionMarkerMetaData tm = new TransactionMarkerMetaData(0,
                beginTimeout, request.getLogin());
            tm.setTransactionId(tid);

            if (logger.isDebugEnabled())
              logger.debug(Translate.get("transaction.begin", String
                  .valueOf(tid)));

            try
            {
              scheduler.begin(tm);

              // Send to load balancer
              loadBalancer.begin(tm);

              // Log the begin
              if (recoveryLog != null)
              {
                recoveryLog.begin(tm);
              }
            }
            catch (SQLException e)
            {
              throw e;
            }
            finally
            {
              // Notify scheduler for completion in any case
              scheduler.beginCompleted(tid);
            }

            tidLoginTable.put(new Long(tid), tm);
          }
          catch (RuntimeException e)
          {
            logger.fatal(Translate.get(
                "fatal.runtime.exception.requestmanager.begin", e));
            throw new SQLException(e.getMessage());
          }
        }
      }
    }
  }

  public int execWriteRequest(AbstractWriteRequest request) throws SQLException
  {
    if (!request.isAutoCommit())
    { // Add this transaction to the list of write transactions
      Long lTid = new Long(request.getTransactionId());
      synchronized (writeTransactions)
      {
        if (!writeTransactions.contains(lTid))
          writeTransactions.add(lTid);
      }
    }
    return execDistributedWriteRequest(request);
  }

  public ControllerResultSet execWriteRequestWithKeys(
      AbstractWriteRequest request) throws SQLException
  {
    if (!request.isAutoCommit())
    { // Add this transaction to the list of write transactions
      Long lTid = new Long(request.getTransactionId());
      synchronized (writeTransactions)
      {
        if (!writeTransactions.contains(lTid))
          writeTransactions.add(lTid);
      }
    }
    return execDistributedWriteRequestWithKeys(request);
  }

  public ControllerResultSet execReadStoredProcedure(StoredProcedure proc)
      throws SQLException
  {
    // If connection is read-only, we don't broadcast
    if (proc.isReadOnly())
      return execDistributedReadStoredProcedureLocally(proc);
    
    if (!proc.isAutoCommit())
    { // Add this transaction to the list of write transactions
      Long lTid = new Long(proc.getTransactionId());
      synchronized (writeTransactions)
      {
        if (!writeTransactions.contains(lTid))
          writeTransactions.add(lTid);
      }
    }
    return execDistributedReadStoredProcedure(proc);
  }

  public int execWriteStoredProcedure(StoredProcedure proc) throws SQLException
  {
    if (!proc.isAutoCommit())
    { // Add this transaction to the list of write transactions
      Long lTid = new Long(proc.getTransactionId());
      synchronized (writeTransactions)
      {
        if (!writeTransactions.contains(lTid))
          writeTransactions.add(lTid);
      }
    }
    return execDistributedWriteStoredProcedure(proc);
  }

  //
  // RAIDb level specific methods
  //

  public abstract void distributedCommit(long transactionId)
      throws SQLException;

  public abstract void distributedRollback(long transactionId)
      throws SQLException;

  public abstract int execDistributedWriteRequest(AbstractWriteRequest request)
      throws SQLException;

  public abstract ControllerResultSet execDistributedWriteRequestWithKeys(
      AbstractWriteRequest request) throws SQLException;

  public abstract ControllerResultSet execDistributedReadStoredProcedure(
      StoredProcedure proc) throws SQLException;

  public abstract int execDistributedWriteStoredProcedure(StoredProcedure proc)
      throws SQLException;

  public ControllerResultSet execDistributedReadStoredProcedureLocally(
      StoredProcedure proc) throws SQLException
  {
    return super.execReadStoredProcedure(proc);
  }

  public int execDistributedWriteStoredProcedureLocally(StoredProcedure proc)
      throws SQLException
  {
    return super.execWriteStoredProcedure(proc);
  }

}

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