/*
* 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.DataInput;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.util.*;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.locks.Lock;
import com.google.common.base.Function;
import com.google.common.base.Objects;
import com.google.common.collect.Iterables;
import com.google.common.util.concurrent.Striped;
import org.apache.cassandra.config.DatabaseDescriptor;
import org.apache.cassandra.db.composites.CellName;
import org.apache.cassandra.db.context.CounterContext;
import org.apache.cassandra.db.filter.NamesQueryFilter;
import org.apache.cassandra.exceptions.WriteTimeoutException;
import org.apache.cassandra.io.IVersionedSerializer;
import org.apache.cassandra.io.util.DataOutputPlus;
import org.apache.cassandra.net.MessageOut;
import org.apache.cassandra.net.MessagingService;
import org.apache.cassandra.service.CacheService;
import org.apache.cassandra.tracing.Tracing;
import org.apache.cassandra.utils.*;
public class CounterMutation implements IMutation
{
public static final CounterMutationSerializer serializer = new CounterMutationSerializer();
private static final Striped<Lock> LOCKS = Striped.lazyWeakLock(DatabaseDescriptor.getConcurrentCounterWriters() * 1024);
private final Mutation mutation;
private final ConsistencyLevel consistency;
public CounterMutation(Mutation mutation, ConsistencyLevel consistency)
{
this.mutation = mutation;
this.consistency = consistency;
}
public String getKeyspaceName()
{
return mutation.getKeyspaceName();
}
public Collection<UUID> getColumnFamilyIds()
{
return mutation.getColumnFamilyIds();
}
public Collection<ColumnFamily> getColumnFamilies()
{
return mutation.getColumnFamilies();
}
public Mutation getMutation()
{
return mutation;
}
public ByteBuffer key()
{
return mutation.key();
}
public ConsistencyLevel consistency()
{
return consistency;
}
public MessageOut<CounterMutation> makeMutationMessage()
{
return new MessageOut<>(MessagingService.Verb.COUNTER_MUTATION, this, serializer);
}
/**
* Applies the counter mutation, returns the result Mutation (for replication to other nodes).
*
* 1. Grabs the striped cell-level locks in the proper order
* 2. Gets the current values of the counters-to-be-modified from the counter cache
* 3. Reads the rest of the current values (cache misses) from the CF
* 4. Writes the updated counter values
* 5. Updates the counter cache
* 6. Releases the lock(s)
*
* See CASSANDRA-4775 and CASSANDRA-6504 for further details.
*
* @return the applied resulting Mutation
*/
public Mutation apply() throws WriteTimeoutException
{
Mutation result = new Mutation(getKeyspaceName(), key());
Keyspace keyspace = Keyspace.open(getKeyspaceName());
int count = 0;
for (ColumnFamily cf : getColumnFamilies())
count += cf.getColumnCount();
List<Lock> locks = new ArrayList<>(count);
Tracing.trace("Acquiring {} counter locks", count);
try
{
grabCounterLocks(keyspace, locks);
for (ColumnFamily cf : getColumnFamilies())
result.add(processModifications(cf));
result.apply();
updateCounterCache(result, keyspace);
return result;
}
finally
{
for (Lock lock : locks)
lock.unlock();
}
}
private void grabCounterLocks(Keyspace keyspace, List<Lock> locks) throws WriteTimeoutException
{
long startTime = System.nanoTime();
for (Lock lock : LOCKS.bulkGet(getCounterLockKeys()))
{
long timeout = TimeUnit.MILLISECONDS.toNanos(getTimeout()) - (System.nanoTime() - startTime);
try
{
if (!lock.tryLock(timeout, TimeUnit.NANOSECONDS))
throw new WriteTimeoutException(WriteType.COUNTER, consistency(), 0, consistency().blockFor(keyspace));
locks.add(lock);
}
catch (InterruptedException e)
{
throw new WriteTimeoutException(WriteType.COUNTER, consistency(), 0, consistency().blockFor(keyspace));
}
}
}
/**
* Returns a wrapper for the Striped#bulkGet() call (via Keyspace#counterLocksFor())
* Striped#bulkGet() depends on Object#hashCode(), so here we make sure that the cf id and the partition key
* all get to be part of the hashCode() calculation, not just the cell name.
*/
private Iterable<Object> getCounterLockKeys()
{
return Iterables.concat(Iterables.transform(getColumnFamilies(), new Function<ColumnFamily, Iterable<Object>>()
{
public Iterable<Object> apply(final ColumnFamily cf)
{
return Iterables.transform(cf, new Function<Cell, Object>()
{
public Object apply(Cell cell)
{
return Objects.hashCode(cf.id(), key(), cell.name());
}
});
}
}));
}
// Replaces all the CounterUpdateCell-s with updated regular CounterCell-s
private ColumnFamily processModifications(ColumnFamily changesCF)
{
ColumnFamilyStore cfs = Keyspace.open(getKeyspaceName()).getColumnFamilyStore(changesCF.id());
ColumnFamily resultCF = changesCF.cloneMeShallow();
List<CounterUpdateCell> counterUpdateCells = new ArrayList<>(changesCF.getColumnCount());
for (Cell cell : changesCF)
{
if (cell instanceof CounterUpdateCell)
counterUpdateCells.add((CounterUpdateCell)cell);
else
resultCF.addColumn(cell);
}
if (counterUpdateCells.isEmpty())
return resultCF; // only DELETEs
ClockAndCount[] currentValues = getCurrentValues(counterUpdateCells, cfs);
for (int i = 0; i < counterUpdateCells.size(); i++)
{
ClockAndCount currentValue = currentValues[i];
CounterUpdateCell update = counterUpdateCells.get(i);
long clock = currentValue.clock + 1L;
long count = currentValue.count + update.delta();
resultCF.addColumn(new BufferCounterCell(update.name(),
CounterContext.instance().createGlobal(CounterId.getLocalId(), clock, count),
update.timestamp()));
}
return resultCF;
}
// Attempt to load the current values(s) from cache. If that fails, read the rest from the cfs.
private ClockAndCount[] getCurrentValues(List<CounterUpdateCell> counterUpdateCells, ColumnFamilyStore cfs)
{
ClockAndCount[] currentValues = new ClockAndCount[counterUpdateCells.size()];
int remaining = counterUpdateCells.size();
if (CacheService.instance.counterCache.getCapacity() != 0)
{
Tracing.trace("Fetching {} counter values from cache", counterUpdateCells.size());
remaining = getCurrentValuesFromCache(counterUpdateCells, cfs, currentValues);
if (remaining == 0)
return currentValues;
}
Tracing.trace("Reading {} counter values from the CF", remaining);
getCurrentValuesFromCFS(counterUpdateCells, cfs, currentValues);
return currentValues;
}
// Returns the count of cache misses.
private int getCurrentValuesFromCache(List<CounterUpdateCell> counterUpdateCells,
ColumnFamilyStore cfs,
ClockAndCount[] currentValues)
{
int cacheMisses = 0;
for (int i = 0; i < counterUpdateCells.size(); i++)
{
ClockAndCount cached = cfs.getCachedCounter(key(), counterUpdateCells.get(i).name());
if (cached != null)
currentValues[i] = cached;
else
cacheMisses++;
}
return cacheMisses;
}
// Reads the missing current values from the CFS.
private void getCurrentValuesFromCFS(List<CounterUpdateCell> counterUpdateCells,
ColumnFamilyStore cfs,
ClockAndCount[] currentValues)
{
SortedSet<CellName> names = new TreeSet<>(cfs.metadata.comparator);
for (int i = 0; i < currentValues.length; i++)
if (currentValues[i] == null)
names.add(counterUpdateCells.get(i).name());
ReadCommand cmd = new SliceByNamesReadCommand(getKeyspaceName(), key(), cfs.metadata.cfName, Long.MIN_VALUE, new NamesQueryFilter(names));
Row row = cmd.getRow(cfs.keyspace);
ColumnFamily cf = row == null ? null : row.cf;
for (int i = 0; i < currentValues.length; i++)
{
if (currentValues[i] != null)
continue;
Cell cell = cf == null ? null : cf.getColumn(counterUpdateCells.get(i).name());
if (cell == null || !cell.isLive()) // absent or a tombstone.
currentValues[i] = ClockAndCount.BLANK;
else
currentValues[i] = CounterContext.instance().getLocalClockAndCount(cell.value());
}
}
private void updateCounterCache(Mutation applied, Keyspace keyspace)
{
if (CacheService.instance.counterCache.getCapacity() == 0)
return;
for (ColumnFamily cf : applied.getColumnFamilies())
{
ColumnFamilyStore cfs = keyspace.getColumnFamilyStore(cf.id());
for (Cell cell : cf)
if (cell instanceof CounterCell)
cfs.putCachedCounter(key(), cell.name(), CounterContext.instance().getLocalClockAndCount(cell.value()));
}
}
public void addAll(IMutation m)
{
if (!(m instanceof CounterMutation))
throw new IllegalArgumentException();
CounterMutation cm = (CounterMutation)m;
mutation.addAll(cm.mutation);
}
public long getTimeout()
{
return DatabaseDescriptor.getCounterWriteRpcTimeout();
}
@Override
public String toString()
{
return toString(false);
}
public String toString(boolean shallow)
{
return String.format("CounterMutation(%s, %s)", mutation.toString(shallow), consistency);
}
public static class CounterMutationSerializer implements IVersionedSerializer<CounterMutation>
{
public void serialize(CounterMutation cm, DataOutputPlus out, int version) throws IOException
{
Mutation.serializer.serialize(cm.mutation, out, version);
out.writeUTF(cm.consistency.name());
}
public CounterMutation deserialize(DataInput in, int version) throws IOException
{
Mutation m = Mutation.serializer.deserialize(in, version);
ConsistencyLevel consistency = Enum.valueOf(ConsistencyLevel.class, in.readUTF());
return new CounterMutation(m, consistency);
}
public long serializedSize(CounterMutation cm, int version)
{
return Mutation.serializer.serializedSize(cm.mutation, version)
+ TypeSizes.NATIVE.sizeof(cm.consistency.name());
}
}
}