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The Apache Cassandra Project develops a highly scalable second-generation distributed database, bringing together Dynamo's fully distributed design and Bigtable's ColumnFamily-based data model.
/*
* 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.cache;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.util.Arrays;
import java.util.List;
import java.util.Objects;
import org.apache.cassandra.db.*;
import org.apache.cassandra.db.filter.ClusteringIndexFilter;
import org.apache.cassandra.db.filter.ClusteringIndexNamesFilter;
import org.apache.cassandra.db.filter.ColumnFilter;
import org.apache.cassandra.db.marshal.ByteBufferAccessor;
import org.apache.cassandra.db.marshal.CompositeType;
import org.apache.cassandra.db.marshal.UTF8Type;
import org.apache.cassandra.db.rows.CellPath;
import org.apache.cassandra.db.rows.RowIterator;
import org.apache.cassandra.db.rows.UnfilteredRowIterators;
import org.apache.cassandra.io.util.DataInputPlus;
import org.apache.cassandra.io.util.DataOutputPlus;
import org.apache.cassandra.schema.ColumnMetadata;
import org.apache.cassandra.schema.Schema;
import org.apache.cassandra.schema.TableMetadata;
import org.apache.cassandra.schema.TableMetadataRef;
import org.apache.cassandra.utils.*;
public final class CounterCacheKey extends CacheKey
{
private static final long EMPTY_SIZE = ObjectSizes.measure(new CounterCacheKey(TableMetadata.builder("ks", "tab")
.addPartitionKeyColumn("pk", UTF8Type.instance)
.build(), ByteBufferUtil.EMPTY_BYTE_BUFFER, ByteBuffer.allocate(1)));
private final byte[] partitionKey;
private final byte[] cellName;
private CounterCacheKey(TableMetadata tableMetadata, byte[] partitionKey, byte[] cellName)
{
super(tableMetadata);
this.partitionKey = partitionKey;
this.cellName = cellName;
}
private CounterCacheKey(TableMetadata tableMetadata, ByteBuffer partitionKey, ByteBuffer cellName)
{
this(tableMetadata, ByteBufferUtil.getArray(partitionKey), ByteBufferUtil.getArray(cellName));
}
public static CounterCacheKey create(TableMetadata tableMetadata, ByteBuffer partitionKey, Clustering clustering, ColumnMetadata c, CellPath path)
{
return new CounterCacheKey(tableMetadata, partitionKey, makeCellName(clustering, c, path));
}
private static ByteBuffer makeCellName(Clustering clustering, ColumnMetadata c, CellPath path)
{
int cs = clustering.size();
ByteBuffer[] values = new ByteBuffer[cs + 1 + (path == null ? 0 : path.size())];
for (int i = 0; i < cs; i++)
values[i] = clustering.bufferAt(i);
values[cs] = c.name.bytes;
if (path != null)
for (int i = 0; i < path.size(); i++)
values[cs + 1 + i] = path.get(i);
return CompositeType.build(ByteBufferAccessor.instance, values);
}
public ByteBuffer partitionKey()
{
return ByteBuffer.wrap(partitionKey);
}
/**
* Reads the value of the counter represented by this key.
*
* @param cfs the store for the table this is a key of.
* @return the value for the counter represented by this key, or {@code null} if there
* is not such counter.
*/
public ByteBuffer readCounterValue(ColumnFamilyStore cfs)
{
TableMetadata metadata = cfs.metadata();
assert metadata.id.equals(tableId) && Objects.equals(metadata.indexName().orElse(null), indexName);
DecoratedKey key = cfs.decorateKey(partitionKey());
int clusteringSize = metadata.comparator.size();
List buffers = CompositeType.splitName(ByteBuffer.wrap(cellName), ByteBufferAccessor.instance);
assert buffers.size() >= clusteringSize + 1; // See makeCellName above
Clustering clustering = Clustering.make(buffers.subList(0, clusteringSize).toArray(new ByteBuffer[clusteringSize]));
ColumnMetadata column = metadata.getColumn(buffers.get(clusteringSize));
// This can theoretically happen if a column is dropped after the cache is saved and we
// try to load it. Not point if failing in any case, just skip the value.
if (column == null)
return null;
CellPath path = column.isComplex() ? CellPath.create(buffers.get(buffers.size() - 1)) : null;
long nowInSec = FBUtilities.nowInSeconds();
ColumnFilter.Builder builder = ColumnFilter.selectionBuilder();
if (path == null)
builder.add(column);
else
builder.select(column, path);
ClusteringIndexFilter filter = new ClusteringIndexNamesFilter(FBUtilities.singleton(clustering, metadata.comparator), false);
SinglePartitionReadCommand cmd = SinglePartitionReadCommand.create(metadata, nowInSec, key, builder.build(), filter);
try (ReadExecutionController controller = cmd.executionController();
RowIterator iter = UnfilteredRowIterators.filter(cmd.queryMemtableAndDisk(cfs, controller), nowInSec))
{
ByteBuffer value = null;
if (column.isStatic())
value = iter.staticRow().getCell(column).buffer();
else if (iter.hasNext())
value = iter.next().getCell(column).buffer();
return value;
}
}
public void write(DataOutputPlus out)
throws IOException
{
ByteArrayUtil.writeWithLength(partitionKey, out);
ByteArrayUtil.writeWithLength(cellName, out);
}
public static CounterCacheKey read(TableMetadata tableMetadata, DataInputPlus in)
throws IOException
{
return new CounterCacheKey(tableMetadata,
ByteBufferUtil.readBytesWithLength(in),
ByteBufferUtil.readBytesWithLength(in));
}
public long unsharedHeapSize()
{
return EMPTY_SIZE
+ ObjectSizes.sizeOfArray(partitionKey)
+ ObjectSizes.sizeOfArray(cellName);
}
@Override
public String toString()
{
TableMetadataRef tableRef = Schema.instance.getTableMetadataRef(tableId);
return String.format("CounterCacheKey(%s, %s, %s, %s)",
tableRef, indexName,
ByteBufferUtil.bytesToHex(ByteBuffer.wrap(partitionKey)),
ByteBufferUtil.bytesToHex(ByteBuffer.wrap(cellName)));
}
@Override
public int hashCode()
{
return Arrays.deepHashCode(new Object[]{tableId, indexName, partitionKey, cellName});
}
@Override
public boolean equals(Object o)
{
if (this == o)
return true;
if (!(o instanceof CounterCacheKey))
return false;
CounterCacheKey cck = (CounterCacheKey) o;
return tableId.equals(cck.tableId)
&& Objects.equals(indexName, cck.indexName)
&& Arrays.equals(partitionKey, cck.partitionKey)
&& Arrays.equals(cellName, cck.cellName);
}
}