/**
* 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.service;
import java.io.*;
import java.lang.management.ManagementFactory;
import java.net.InetAddress;
import java.nio.ByteBuffer;
import java.util.*;
import java.util.concurrent.*;
import javax.management.MBeanServer;
import javax.management.ObjectName;
import com.google.common.collect.HashMultimap;
import com.google.common.collect.Multimap;
import org.apache.commons.lang.ArrayUtils;
import org.apache.commons.lang.StringUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.apache.cassandra.concurrent.Stage;
import org.apache.cassandra.concurrent.StageManager;
import org.apache.cassandra.config.DatabaseDescriptor;
import org.apache.cassandra.db.*;
import org.apache.cassandra.db.filter.QueryFilter;
import org.apache.cassandra.dht.AbstractBounds;
import org.apache.cassandra.dht.Bounds;
import org.apache.cassandra.dht.IPartitioner;
import org.apache.cassandra.dht.Token;
import org.apache.cassandra.gms.Gossiper;
import org.apache.cassandra.locator.AbstractReplicationStrategy;
import org.apache.cassandra.locator.TokenMetadata;
import org.apache.cassandra.net.IAsyncCallback;
import org.apache.cassandra.net.Message;
import org.apache.cassandra.net.MessagingService;
import org.apache.cassandra.thrift.*;
import org.apache.cassandra.utils.*;
import static com.google.common.base.Charsets.UTF_8;
public class StorageProxy implements StorageProxyMBean
{
private static final Logger logger = LoggerFactory.getLogger(StorageProxy.class);
// mbean stuff
private static final LatencyTracker readStats = new LatencyTracker();
private static final LatencyTracker rangeStats = new LatencyTracker();
private static final LatencyTracker writeStats = new LatencyTracker();
private static boolean hintedHandoffEnabled = DatabaseDescriptor.hintedHandoffEnabled();
private static int maxHintWindow = DatabaseDescriptor.getMaxHintWindow();
public static final String UNREACHABLE = "UNREACHABLE";
public static final StorageProxy instance = new StorageProxy();
private StorageProxy() {}
static
{
MBeanServer mbs = ManagementFactory.getPlatformMBeanServer();
try
{
mbs.registerMBean(new StorageProxy(), new ObjectName("org.apache.cassandra.db:type=StorageProxy"));
}
catch (Exception e)
{
throw new RuntimeException(e);
}
}
/**
* Use this method to have these RowMutations applied
* across all replicas. This method will take care
* of the possibility of a replica being down and hint
* the data across to some other replica.
*
* @param mutations the mutations to be applied across the replicas
* @param consistency_level the consistency level for the operation
*/
public static void mutate(List<RowMutation> mutations, ConsistencyLevel consistency_level) throws UnavailableException, TimeoutException
{
long startTime = System.nanoTime();
List<IWriteResponseHandler> responseHandlers = new ArrayList<IWriteResponseHandler>();
RowMutation mostRecentRowMutation = null;
StorageService ss = StorageService.instance;
String localDataCenter = DatabaseDescriptor.getEndpointSnitch().getDatacenter(FBUtilities.getLocalAddress());
try
{
for (RowMutation rm : mutations)
{
mostRecentRowMutation = rm;
String table = rm.getTable();
AbstractReplicationStrategy rs = Table.open(table).getReplicationStrategy();
List<InetAddress> naturalEndpoints = ss.getNaturalEndpoints(table, rm.key());
Collection<InetAddress> writeEndpoints = ss.getTokenMetadata().getWriteEndpoints(StorageService.getPartitioner().getToken(rm.key()), table, naturalEndpoints);
Multimap<InetAddress, InetAddress> hintedEndpoints = rs.getHintedEndpoints(writeEndpoints);
final IWriteResponseHandler responseHandler = rs.getWriteResponseHandler(writeEndpoints, hintedEndpoints, consistency_level);
// exit early if we can't fulfill the CL at this time
responseHandler.assureSufficientLiveNodes();
responseHandlers.add(responseHandler);
// Multimap that holds onto all the messages and addresses meant for a specific datacenter
Map<String, Multimap<Message, InetAddress>> dcMessages = new HashMap<String, Multimap<Message, InetAddress>>(hintedEndpoints.size());
Message unhintedMessage = null;
for (Map.Entry<InetAddress, Collection<InetAddress>> entry : hintedEndpoints.asMap().entrySet())
{
InetAddress destination = entry.getKey();
Collection<InetAddress> targets = entry.getValue();
String dc = DatabaseDescriptor.getEndpointSnitch().getDatacenter(destination);
if (targets.size() == 1 && targets.iterator().next().equals(destination))
{
// unhinted writes
if (destination.equals(FBUtilities.getLocalAddress()))
{
insertLocal(rm, responseHandler);
}
else
{
// belongs on a different server
if (unhintedMessage == null)
unhintedMessage = rm.makeRowMutationMessage();
if (logger.isDebugEnabled())
logger.debug("insert writing key " + ByteBufferUtil.bytesToHex(rm.key()) + " to " + destination);
Multimap<Message, InetAddress> messages = dcMessages.get(dc);
if (messages == null)
{
messages = HashMultimap.create();
dcMessages.put(dc, messages);
}
messages.put(unhintedMessage, destination);
}
}
else
{
// hinted messages are unique, so there is no point to adding a hop by forwarding via another node.
// thus, we use sendRR/sendOneWay directly here.
Message hintedMessage = rm.makeRowMutationMessage();
for (InetAddress target : targets)
{
if (!target.equals(destination))
{
addHintHeader(hintedMessage, target);
if (logger.isDebugEnabled())
logger.debug("insert writing key " + ByteBufferUtil.bytesToHex(rm.key()) + " to " + destination + " for " + target);
}
}
// non-destination hints are part of the callback and count towards consistency only under CL.ANY
if (writeEndpoints.contains(destination) || consistency_level == ConsistencyLevel.ANY)
MessagingService.instance().sendRR(hintedMessage, destination, responseHandler);
else
MessagingService.instance().sendOneWay(hintedMessage, destination);
}
}
sendMessages(localDataCenter, dcMessages, responseHandler);
}
// wait for writes. throws timeoutexception if necessary
for (IWriteResponseHandler responseHandler : responseHandlers)
responseHandler.get();
}
catch (IOException e)
{
if (mostRecentRowMutation == null)
throw new RuntimeException("no mutations were seen but found an error during write anyway", e);
else
throw new RuntimeException("error writing key " + ByteBufferUtil.bytesToHex(mostRecentRowMutation.key()), e);
}
finally
{
writeStats.addNano(System.nanoTime() - startTime);
}
}
/**
* for each datacenter, send a message to one node to relay the write to other replicas
*/
private static void sendMessages(String localDataCenter, Map<String, Multimap<Message, InetAddress>> dcMessages, IWriteResponseHandler handler)
throws IOException
{
for (Map.Entry<String, Multimap<Message, InetAddress>> entry: dcMessages.entrySet())
{
String dataCenter = entry.getKey();
// send the messages corresponding to this datacenter
for (Map.Entry<Message, Collection<InetAddress>> messages: entry.getValue().asMap().entrySet())
{
Message message = messages.getKey();
// a single message object is used for unhinted writes, so clean out any forwards
// from previous loop iterations
message.removeHeader(RowMutation.FORWARD_HEADER);
if (dataCenter.equals(localDataCenter) || StorageService.instance.useEfficientCrossDCWrites())
{
// direct writes to local DC or old Cassadra versions
for (InetAddress destination : messages.getValue())
MessagingService.instance().sendRR(message, destination, handler);
}
else
{
// Non-local DC. First endpoint in list is the destination for this group
Iterator<InetAddress> iter = messages.getValue().iterator();
InetAddress target = iter.next();
// Add all the other destinations of the same message as a header in the primary message.
while (iter.hasNext())
{
InetAddress destination = iter.next();
// group all nodes in this DC as forward headers on the primary message
ByteArrayOutputStream bos = new ByteArrayOutputStream();
DataOutputStream dos = new DataOutputStream(bos);
// append to older addresses
byte[] previousHints = message.getHeader(RowMutation.FORWARD_HEADER);
if (previousHints != null)
dos.write(previousHints);
dos.write(destination.getAddress());
message.setHeader(RowMutation.FORWARD_HEADER, bos.toByteArray());
}
// send the combined message + forward headers
MessagingService.instance().sendRR(message, target, handler);
}
}
}
}
private static void addHintHeader(Message message, InetAddress target) throws IOException
{
ByteArrayOutputStream bos = new ByteArrayOutputStream();
DataOutputStream dos = new DataOutputStream(bos);
byte[] previousHints = message.getHeader(RowMutation.HINT);
if (previousHints != null)
{
dos.write(previousHints);
}
ByteBufferUtil.writeWithShortLength(ByteBuffer.wrap(target.getHostAddress().getBytes(UTF_8)), dos);
message.setHeader(RowMutation.HINT, bos.toByteArray());
}
private static void insertLocal(final RowMutation rm, final IWriteResponseHandler responseHandler)
{
if (logger.isDebugEnabled())
logger.debug("insert writing local " + rm.toString(true));
Runnable runnable = new WrappedRunnable()
{
public void runMayThrow() throws IOException
{
rm.deepCopy().apply();
responseHandler.response(null);
}
};
StageManager.getStage(Stage.MUTATION).execute(runnable);
}
/**
* Performs the actual reading of a row out of the StorageService, fetching
* a specific set of column names from a given column family.
*/
public static List<Row> read(List<ReadCommand> commands, ConsistencyLevel consistency_level)
throws IOException, UnavailableException, TimeoutException, InvalidRequestException
{
if (StorageService.instance.isBootstrapMode())
throw new UnavailableException();
long startTime = System.nanoTime();
List<Row> rows;
try
{
rows = fetchRows(commands, consistency_level);
}
finally
{
readStats.addNano(System.nanoTime() - startTime);
}
return rows;
}
/**
* This function executes local and remote reads, and blocks for the results:
*
* 1. Get the replica locations, sorted by response time according to the snitch
* 2. Send a data request to the closest replica, and digest requests to either
* a) all the replicas, if read repair is enabled
* b) the closest R-1 replicas, where R is the number required to satisfy the ConsistencyLevel
* 3. Wait for a response from R replicas
* 4. If the digests (if any) match the data return the data
* 5. else carry out read repair by getting data from all the nodes.
*/
private static List<Row> fetchRows(List<ReadCommand> commands, ConsistencyLevel consistency_level) throws IOException, UnavailableException, TimeoutException
{
List<ReadCallback<Row>> readCallbacks = new ArrayList<ReadCallback<Row>>();
List<Row> rows = new ArrayList<Row>();
// send out read requests
for (ReadCommand command: commands)
{
assert !command.isDigestQuery();
logger.debug("Command/ConsistencyLevel is {}/{}", command, consistency_level);
List<InetAddress> endpoints = StorageService.instance.getLiveNaturalEndpoints(command.table, command.key);
DatabaseDescriptor.getEndpointSnitch().sortByProximity(FBUtilities.getLocalAddress(), endpoints);
RowDigestResolver resolver = new RowDigestResolver(command.table, command.key);
ReadCallback<Row> handler = getReadCallback(resolver, command, consistency_level, endpoints);
handler.assureSufficientLiveNodes();
assert !handler.endpoints.isEmpty();
// The data-request message is sent to dataPoint, the node that will actually get
// the data for us. The other replicas are only sent a digest query.
ReadCommand digestCommand = null;
if (handler.endpoints.size() > 1)
{
digestCommand = command.copy();
digestCommand.setDigestQuery(true);
}
InetAddress dataPoint = handler.endpoints.get(0);
if (dataPoint.equals(FBUtilities.getLocalAddress()))
{
if (logger.isDebugEnabled())
logger.debug("reading data locally");
StageManager.getStage(Stage.READ).execute(new LocalReadRunnable(command, handler));
}
else
{
Message message = command.makeReadMessage();
if (logger.isDebugEnabled())
logger.debug("reading data from " + dataPoint);
MessagingService.instance().sendRR(message, dataPoint, handler);
}
// We lazy-construct the digest Message object since it may not be necessary if we
// are doing a local digest read, or no digest reads at all.
Message digestMessage = null;
for (InetAddress digestPoint : handler.endpoints.subList(1, handler.endpoints.size()))
{
if (digestPoint.equals(FBUtilities.getLocalAddress()))
{
if (logger.isDebugEnabled())
logger.debug("reading digest locally");
StageManager.getStage(Stage.READ).execute(new LocalReadRunnable(digestCommand, handler));
}
else
{
if (digestMessage == null)
digestMessage = digestCommand.makeReadMessage();
if (logger.isDebugEnabled())
logger.debug("reading digest for from " + digestPoint);
MessagingService.instance().sendRR(digestMessage, digestPoint, handler);
}
}
readCallbacks.add(handler);
}
// read results and make a second pass for any digest mismatches
List<RepairCallback<Row>> repairResponseHandlers = null;
for (int i = 0; i < commands.size(); i++)
{
ReadCallback<Row> handler = readCallbacks.get(i);
Row row;
ReadCommand command = commands.get(i);
try
{
long startTime2 = System.currentTimeMillis();
row = handler.get(); // CL.ONE is special cased here to ignore digests even if some have arrived
if (row != null)
rows.add(row);
if (logger.isDebugEnabled())
logger.debug("Read: " + (System.currentTimeMillis() - startTime2) + " ms.");
}
catch (DigestMismatchException ex)
{
if (logger.isDebugEnabled())
logger.debug("Digest mismatch:", ex);
RowRepairResolver resolver = new RowRepairResolver(command.table, command.key);
RepairCallback<Row> repairHandler = new RepairCallback<Row>(resolver, handler.endpoints);
Message messageRepair = command.makeReadMessage();
for (InetAddress endpoint : handler.endpoints)
MessagingService.instance().sendRR(messageRepair, endpoint, repairHandler);
if (repairResponseHandlers == null)
repairResponseHandlers = new ArrayList<RepairCallback<Row>>();
repairResponseHandlers.add(repairHandler);
}
}
// read the results for the digest mismatch retries
if (repairResponseHandlers != null)
{
for (RepairCallback<Row> handler : repairResponseHandlers)
{
try
{
Row row = handler.get();
if (row != null)
rows.add(row);
}
catch (DigestMismatchException e)
{
throw new AssertionError(e); // full data requested from each node here, no digests should be sent
}
}
}
return rows;
}
static class LocalReadRunnable extends WrappedRunnable
{
private final ReadCommand command;
private final ReadCallback<Row> handler;
private final long start = System.currentTimeMillis();
LocalReadRunnable(ReadCommand command, ReadCallback<Row> handler)
{
this.command = command;
this.handler = handler;
}
protected void runMayThrow() throws IOException
{
if (logger.isDebugEnabled())
logger.debug("LocalReadRunnable reading " + command);
Table table = Table.open(command.table);
ReadResponse result = ReadVerbHandler.getResponse(command, command.getRow(table));
MessagingService.instance().addLatency(FBUtilities.getLocalAddress(), System.currentTimeMillis() - start);
handler.response(result);
}
}
static <T> ReadCallback<T> getReadCallback(IResponseResolver<T> resolver, IReadCommand command, ConsistencyLevel consistencyLevel, List<InetAddress> endpoints)
{
if (consistencyLevel.equals(ConsistencyLevel.LOCAL_QUORUM) || consistencyLevel.equals(ConsistencyLevel.EACH_QUORUM))
{
return new DatacenterReadCallback(resolver, consistencyLevel, command, endpoints);
}
return new ReadCallback(resolver, consistencyLevel, command, endpoints);
}
/*
* This function executes the read protocol locally. Consistency checks are performed in the background.
*/
public static List<Row> getRangeSlice(RangeSliceCommand command, ConsistencyLevel consistency_level)
throws IOException, UnavailableException, TimeoutException
{
if (logger.isDebugEnabled())
logger.debug(command.toString());
long startTime = System.nanoTime();
List<Row> rows;
// now scan until we have enough results
try
{
rows = new ArrayList<Row>(command.max_keys);
List<AbstractBounds> ranges = getRestrictedRanges(command.range);
for (AbstractBounds range : ranges)
{
List<InetAddress> liveEndpoints = StorageService.instance.getLiveNaturalEndpoints(command.keyspace, range.right);
DatabaseDescriptor.getEndpointSnitch().sortByProximity(FBUtilities.getLocalAddress(), liveEndpoints);
if (consistency_level == ConsistencyLevel.ONE && !liveEndpoints.isEmpty() && liveEndpoints.get(0).equals(FBUtilities.getLocalAddress()))
{
if (logger.isDebugEnabled())
logger.debug("local range slice");
ColumnFamilyStore cfs = Table.open(command.keyspace).getColumnFamilyStore(command.column_family);
try
{
rows.addAll(cfs.getRangeSlice(command.super_column,
range,
command.max_keys,
QueryFilter.getFilter(command.predicate, cfs.getComparator())));
}
catch (ExecutionException e)
{
throw new RuntimeException(e.getCause());
}
catch (InterruptedException e)
{
throw new AssertionError(e);
}
}
else
{
RangeSliceCommand c2 = new RangeSliceCommand(command.keyspace, command.column_family, command.super_column, command.predicate, range, command.max_keys);
Message message = c2.getMessage();
// collect replies and resolve according to consistency level
RangeSliceResponseResolver resolver = new RangeSliceResponseResolver(command.keyspace, liveEndpoints);
ReadCallback<List<Row>> handler = getReadCallback(resolver, command, consistency_level, liveEndpoints);
handler.assureSufficientLiveNodes();
for (InetAddress endpoint : handler.endpoints)
{
MessagingService.instance().sendRR(message, endpoint, handler);
if (logger.isDebugEnabled())
logger.debug("reading " + c2 + " from " + endpoint);
}
// if we're done, great, otherwise, move to the next range
try
{
if (logger.isDebugEnabled())
{
for (Row row : handler.get())
{
logger.debug("range slices read " + row.key);
}
}
rows.addAll(handler.get());
}
catch (DigestMismatchException e)
{
throw new AssertionError(e); // no digests in range slices yet
}
}
if (rows.size() >= command.max_keys)
break;
}
}
finally
{
rangeStats.addNano(System.nanoTime() - startTime);
}
return rows.size() > command.max_keys ? rows.subList(0, command.max_keys) : rows;
}
/**
* initiate a request/response session with each live node to check whether or not everybody is using the same
* migration id. This is useful for determining if a schema change has propagated through the cluster. Disagreement
* is assumed if any node fails to respond.
*/
public static Map<String, List<String>> describeSchemaVersions()
{
final String myVersion = DatabaseDescriptor.getDefsVersion().toString();
final Map<InetAddress, UUID> versions = new ConcurrentHashMap<InetAddress, UUID>();
final Set<InetAddress> liveHosts = Gossiper.instance.getLiveMembers();
final CountDownLatch latch = new CountDownLatch(liveHosts.size());
IAsyncCallback cb = new IAsyncCallback()
{
public void response(Message message)
{
// record the response from the remote node.
logger.debug("Received schema check response from " + message.getFrom().getHostAddress());
UUID theirVersion = UUID.fromString(new String(message.getMessageBody()));
versions.put(message.getFrom(), theirVersion);
latch.countDown();
}
public boolean isLatencyForSnitch()
{
return false;
}
};
// an empty message acts as a request to the SchemaCheckVerbHandler.
for (InetAddress endpoint : liveHosts)
{
Message message = new Message(FBUtilities.getLocalAddress(), StorageService.Verb.SCHEMA_CHECK, ArrayUtils.EMPTY_BYTE_ARRAY);
MessagingService.instance().sendRR(message, endpoint, cb);
}
try
{
// wait for as long as possible. timeout-1s if possible.
latch.await(DatabaseDescriptor.getRpcTimeout(), TimeUnit.MILLISECONDS);
}
catch (InterruptedException ex)
{
throw new AssertionError("This latch shouldn't have been interrupted.");
}
logger.debug("My version is " + myVersion);
// maps versions to hosts that are on that version.
Map<String, List<String>> results = new HashMap<String, List<String>>();
Set<InetAddress> allHosts = new HashSet<InetAddress>();
allHosts.addAll(Gossiper.instance.getLiveMembers());
allHosts.addAll(Gossiper.instance.getUnreachableMembers());
for (InetAddress host : allHosts)
{
UUID version = versions.get(host);
String stringVersion = version == null ? UNREACHABLE : version.toString();
List<String> hosts = results.get(stringVersion);
if (hosts == null)
{
hosts = new ArrayList<String>();
results.put(stringVersion, hosts);
}
hosts.add(host.getHostAddress());
}
// we're done: the results map is ready to return to the client. the rest is just debug logging:
if (results.get(UNREACHABLE) != null)
logger.debug("Hosts not in agreement. Didn't get a response from everybody: " + StringUtils.join(results.get(UNREACHABLE), ","));
for (Map.Entry<String, List<String>> entry : results.entrySet())
{
// check for version disagreement. log the hosts that don't agree.
if (entry.getKey().equals(UNREACHABLE) || entry.getKey().equals(myVersion))
continue;
for (String host : entry.getValue())
logger.debug("%s disagrees (%s)", host, entry.getKey());
}
if (results.size() == 1)
logger.debug("Schemas are in agreement.");
return results;
}
/**
* Compute all ranges we're going to query, in sorted order. Nodes can be replica destinations for many ranges,
* so we need to restrict each scan to the specific range we want, or else we'd get duplicate results.
*/
static List<AbstractBounds> getRestrictedRanges(final AbstractBounds queryRange)
{
// special case for bounds containing exactly 1 (non-minimum) token
if (queryRange instanceof Bounds && queryRange.left.equals(queryRange.right) && !queryRange.left.equals(StorageService.getPartitioner().getMinimumToken()))
{
if (logger.isDebugEnabled())
logger.debug("restricted single token match for query " + queryRange);
return Collections.singletonList(queryRange);
}
TokenMetadata tokenMetadata = StorageService.instance.getTokenMetadata();
List<AbstractBounds> ranges = new ArrayList<AbstractBounds>();
// divide the queryRange into pieces delimited by the ring and minimum tokens
Iterator<Token> ringIter = TokenMetadata.ringIterator(tokenMetadata.sortedTokens(), queryRange.left, true);
AbstractBounds remainder = queryRange;
while (ringIter.hasNext())
{
Token token = ringIter.next();
if (remainder == null || !(remainder.left.equals(token) || remainder.contains(token)))
// no more splits
break;
Pair<AbstractBounds,AbstractBounds> splits = remainder.split(token);
if (splits.left != null)
ranges.add(splits.left);
remainder = splits.right;
}
if (remainder != null)
ranges.add(remainder);
if (logger.isDebugEnabled())
logger.debug("restricted ranges for query " + queryRange + " are " + ranges);
return ranges;
}
public long getReadOperations()
{
return readStats.getOpCount();
}
public long getTotalReadLatencyMicros()
{
return readStats.getTotalLatencyMicros();
}
public double getRecentReadLatencyMicros()
{
return readStats.getRecentLatencyMicros();
}
public long[] getTotalReadLatencyHistogramMicros()
{
return readStats.getTotalLatencyHistogramMicros();
}
public long[] getRecentReadLatencyHistogramMicros()
{
return readStats.getRecentLatencyHistogramMicros();
}
public long getRangeOperations()
{
return rangeStats.getOpCount();
}
public long getTotalRangeLatencyMicros()
{
return rangeStats.getTotalLatencyMicros();
}
public double getRecentRangeLatencyMicros()
{
return rangeStats.getRecentLatencyMicros();
}
public long[] getTotalRangeLatencyHistogramMicros()
{
return rangeStats.getTotalLatencyHistogramMicros();
}
public long[] getRecentRangeLatencyHistogramMicros()
{
return rangeStats.getRecentLatencyHistogramMicros();
}
public long getWriteOperations()
{
return writeStats.getOpCount();
}
public long getTotalWriteLatencyMicros()
{
return writeStats.getTotalLatencyMicros();
}
public double getRecentWriteLatencyMicros()
{
return writeStats.getRecentLatencyMicros();
}
public long[] getTotalWriteLatencyHistogramMicros()
{
return writeStats.getTotalLatencyHistogramMicros();
}
public long[] getRecentWriteLatencyHistogramMicros()
{
return writeStats.getRecentLatencyHistogramMicros();
}
public static List<Row> scan(final String keyspace, String column_family, IndexClause index_clause, SlicePredicate column_predicate, ConsistencyLevel consistency_level)
throws IOException, TimeoutException, UnavailableException
{
IPartitioner p = StorageService.getPartitioner();
Token leftToken = index_clause.start_key == null ? p.getMinimumToken() : p.getToken(index_clause.start_key);
List<AbstractBounds> ranges = getRestrictedRanges(new Bounds(leftToken, p.getMinimumToken()));
logger.debug("scan ranges are " + StringUtils.join(ranges, ","));
// now scan until we have enough results
List<Row> rows = new ArrayList<Row>(index_clause.count);
for (AbstractBounds range : ranges)
{
List<InetAddress> liveEndpoints = StorageService.instance.getLiveNaturalEndpoints(keyspace, range.right);
DatabaseDescriptor.getEndpointSnitch().sortByProximity(FBUtilities.getLocalAddress(), liveEndpoints);
// collect replies and resolve according to consistency level
RangeSliceResponseResolver resolver = new RangeSliceResponseResolver(keyspace, liveEndpoints);
IReadCommand iCommand = new IReadCommand()
{
public String getKeyspace()
{
return keyspace;
}
};
ReadCallback<List<Row>> handler = getReadCallback(resolver, iCommand, consistency_level, liveEndpoints);
handler.assureSufficientLiveNodes();
IndexScanCommand command = new IndexScanCommand(keyspace, column_family, index_clause, column_predicate, range);
Message message = command.getMessage();
for (InetAddress endpoint : handler.endpoints)
{
MessagingService.instance().sendRR(message, endpoint, handler);
if (logger.isDebugEnabled())
logger.debug("reading " + command + " from " + endpoint);
}
List<Row> theseRows;
try
{
theseRows = handler.get();
}
catch (DigestMismatchException e)
{
throw new RuntimeException(e);
}
rows.addAll(theseRows);
if (logger.isDebugEnabled())
{
for (Row row : theseRows)
logger.debug("read " + row);
}
if (rows.size() >= index_clause.count)
return rows.subList(0, index_clause.count);
}
return rows;
}
public boolean getHintedHandoffEnabled()
{
return hintedHandoffEnabled;
}
public void setHintedHandoffEnabled(boolean b)
{
hintedHandoffEnabled = b;
}
public static boolean isHintedHandoffEnabled()
{
return hintedHandoffEnabled;
}
public int getMaxHintWindow()
{
return maxHintWindow;
}
public void setMaxHintWindow(int ms)
{
maxHintWindow = ms;
}
public static boolean shouldHint(InetAddress ep)
{
return Gossiper.instance.getEndpointDowntime(ep) <= maxHintWindow;
}
/**
* Performs the truncate operatoin, which effectively deletes all data from
* the column family cfname
* @param keyspace
* @param cfname
* @throws UnavailableException If some of the hosts in the ring are down.
* @throws TimeoutException
* @throws IOException
*/
public static void truncateBlocking(String keyspace, String cfname) throws UnavailableException, TimeoutException, IOException
{
logger.debug("Starting a blocking truncate operation on keyspace {}, CF ", keyspace, cfname);
if (isAnyHostDown())
{
logger.info("Cannot perform truncate, some hosts are down");
// Since the truncate operation is so aggressive and is typically only
// invoked by an admin, for simplicity we require that all nodes are up
// to perform the operation.
throw new UnavailableException();
}
Set<InetAddress> allEndpoints = Gossiper.instance.getLiveMembers();
int blockFor = allEndpoints.size();
final TruncateResponseHandler responseHandler = new TruncateResponseHandler(blockFor);
// Send out the truncate calls and track the responses with the callbacks.
logger.debug("Starting to send truncate messages to hosts {}", allEndpoints);
Truncation truncation = new Truncation(keyspace, cfname);
Message message = truncation.makeTruncationMessage();
for (InetAddress endpoint : allEndpoints)
MessagingService.instance().sendRR(message, endpoint, responseHandler);
// Wait for all
logger.debug("Sent all truncate messages, now waiting for {} responses", blockFor);
responseHandler.get();
logger.debug("truncate done");
}
/**
* Asks the gossiper if there are any nodes that are currently down.
* @return true if the gossiper thinks all nodes are up.
*/
private static boolean isAnyHostDown()
{
return !Gossiper.instance.getUnreachableMembers().isEmpty();
}
}