/**
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.cassandra.db;
import java.io.IOException;
import java.util.List;
import org.apache.cassandra.config.DatabaseDescriptor;
import org.apache.cassandra.io.DataInputBuffer;
import org.apache.cassandra.io.DataOutputBuffer;
import org.apache.cassandra.net.EndPoint;
import org.apache.cassandra.net.IVerbHandler;
import org.apache.cassandra.net.Message;
import org.apache.cassandra.net.MessagingService;
import org.apache.cassandra.service.StorageService;
import org.apache.cassandra.utils.LogUtil;
import org.apache.log4j.Logger;
/**
* Author : Avinash Lakshman ( alakshman@facebook.com) & Prashant Malik ( pmalik@facebook.com )
*/
public class ReadVerbHandler implements IVerbHandler
{
protected static class ReadContext
{
protected DataInputBuffer bufIn_ = new DataInputBuffer();
protected DataOutputBuffer bufOut_ = new DataOutputBuffer();
}
private static Logger logger_ = Logger.getLogger( ReadVerbHandler.class );
/* We use this so that we can reuse the same row mutation context for the mutation. */
private static ThreadLocal<ReadVerbHandler.ReadContext> tls_ = new InheritableThreadLocal<ReadVerbHandler.ReadContext>();
protected static ReadVerbHandler.ReadContext getCurrentReadContext()
{
return tls_.get();
}
protected static void setCurrentReadContext(ReadVerbHandler.ReadContext readContext)
{
tls_.set(readContext);
}
public void doVerb(Message message)
{
byte[] body = (byte[])message.getMessageBody()[0];
/* Obtain a Read Context from TLS */
ReadContext readCtx = tls_.get();
if ( readCtx == null )
{
readCtx = new ReadContext();
tls_.set(readCtx);
}
readCtx.bufIn_.reset(body, body.length);
try
{
ReadCommand readCommand = ReadCommand.serializer().deserialize(readCtx.bufIn_);
Table table = Table.open(readCommand.table);
Row row = null;
long start = System.currentTimeMillis();
row = readCommand.getRow(table);
logger_.info("getRow() TIME: " + (System.currentTimeMillis() - start) + " ms.");
start = System.currentTimeMillis();
ReadResponse readResponse = null;
if(readCommand.isDigestQuery())
{
readResponse = new ReadResponse(table.getTableName(), row.digest());
}
else
{
readResponse = new ReadResponse(table.getTableName(), row);
}
readResponse.setIsDigestQuery(readCommand.isDigestQuery());
/* serialize the ReadResponseMessage. */
readCtx.bufOut_.reset();
start = System.currentTimeMillis();
ReadResponse.serializer().serialize(readResponse, readCtx.bufOut_);
logger_.info("serialize TIME: " + (System.currentTimeMillis() - start) + " ms.");
byte[] bytes = new byte[readCtx.bufOut_.getLength()];
start = System.currentTimeMillis();
System.arraycopy(readCtx.bufOut_.getData(), 0, bytes, 0, bytes.length);
logger_.info("copy TIME: " + (System.currentTimeMillis() - start) + " ms.");
Message response = message.getReply( StorageService.getLocalStorageEndPoint(), new Object[]{bytes} );
MessagingService.getMessagingInstance().sendOneWay(response, message.getFrom());
logger_.info("ReadVerbHandler TIME 2: " + (System.currentTimeMillis() - start) + " ms.");
/* Do read repair if header of the message says so */
String repair = new String( message.getHeader(ReadCommand.DO_REPAIR) );
if ( repair.equals( ReadCommand.DO_REPAIR) )
doReadRepair(row, readCommand);
}
catch ( IOException ex)
{
logger_.info( LogUtil.throwableToString(ex) );
}
catch ( ColumnFamilyNotDefinedException ex)
{
logger_.info( LogUtil.throwableToString(ex) );
}
}
private void doReadRepair(Row row, ReadCommand readCommand)
{
if ( DatabaseDescriptor.getConsistencyCheck() )
{
List<EndPoint> endpoints = StorageService.instance().getNLiveStorageEndPoint(readCommand.key);
/* Remove the local storage endpoint from the list. */
endpoints.remove( StorageService.getLocalStorageEndPoint() );
if(readCommand.columnNames.size() == 0)
{
if( readCommand.start >= 0 && readCommand.count < Integer.MAX_VALUE)
{
StorageService.instance().doConsistencyCheck(row, endpoints, readCommand.columnFamilyColumn, readCommand.start, readCommand.count);
}
if( readCommand.sinceTimestamp > 0)
{
StorageService.instance().doConsistencyCheck(row, endpoints, readCommand.columnFamilyColumn, readCommand.sinceTimestamp);
}
}
else
{
StorageService.instance().doConsistencyCheck(row, endpoints, readCommand.columnFamilyColumn, readCommand.columnNames);
}
}
}
}