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* 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.
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package org.apache.cassandra.io.sstable.format.big;
import com.google.common.util.concurrent.RateLimiter;
import org.apache.cassandra.cache.KeyCacheKey;
import org.apache.cassandra.config.CFMetaData;
import org.apache.cassandra.db.DataRange;
import org.apache.cassandra.db.DecoratedKey;
import org.apache.cassandra.db.RowIndexEntry;
import org.apache.cassandra.db.RowPosition;
import org.apache.cassandra.db.columniterator.OnDiskAtomIterator;
import org.apache.cassandra.db.compaction.ICompactionScanner;
import org.apache.cassandra.db.composites.CellName;
import org.apache.cassandra.db.filter.ColumnSlice;
import org.apache.cassandra.dht.IPartitioner;
import org.apache.cassandra.dht.Range;
import org.apache.cassandra.dht.Token;
import org.apache.cassandra.io.sstable.Component;
import org.apache.cassandra.io.sstable.CorruptSSTableException;
import org.apache.cassandra.io.sstable.Descriptor;
import org.apache.cassandra.io.sstable.format.SSTableReader;
import org.apache.cassandra.io.sstable.metadata.StatsMetadata;
import org.apache.cassandra.io.util.FileDataInput;
import org.apache.cassandra.io.util.FileUtils;
import org.apache.cassandra.tracing.Tracing;
import org.apache.cassandra.utils.ByteBufferUtil;
import org.apache.cassandra.utils.Pair;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.util.*;
/**
* SSTableReaders are open()ed by Keyspace.onStart; after that they are created by SSTableWriter.renameAndOpen.
* Do not re-call open() on existing SSTable files; use the references kept by ColumnFamilyStore post-start instead.
*/
public class BigTableReader extends SSTableReader
{
private static final Logger logger = LoggerFactory.getLogger(BigTableReader.class);
BigTableReader(Descriptor desc, Set<Component> components, CFMetaData metadata, IPartitioner partitioner, Long maxDataAge, StatsMetadata sstableMetadata, OpenReason openReason)
{
super(desc, components, metadata, partitioner, maxDataAge, sstableMetadata, openReason);
}
public OnDiskAtomIterator iterator(DecoratedKey key, SortedSet<CellName> columns)
{
return new SSTableNamesIterator(this, key, columns);
}
public OnDiskAtomIterator iterator(FileDataInput input, DecoratedKey key, SortedSet<CellName> columns, RowIndexEntry indexEntry )
{
return new SSTableNamesIterator(this, input, key, columns, indexEntry);
}
public OnDiskAtomIterator iterator(DecoratedKey key, ColumnSlice[] slices, boolean reverse)
{
return new SSTableSliceIterator(this, key, slices, reverse);
}
public OnDiskAtomIterator iterator(FileDataInput input, DecoratedKey key, ColumnSlice[] slices, boolean reverse, RowIndexEntry indexEntry)
{
return new SSTableSliceIterator(this, input, key, slices, reverse, indexEntry);
}
/**
*
* @param dataRange filter to use when reading the columns
* @return A Scanner for seeking over the rows of the SSTable.
*/
public ICompactionScanner getScanner(DataRange dataRange, RateLimiter limiter)
{
return new BigTableScanner(this, dataRange, limiter);
}
/**
* Direct I/O SSTableScanner over a defined collection of ranges of tokens.
*
* @param ranges the range of keys to cover
* @return A Scanner for seeking over the rows of the SSTable.
*/
public ICompactionScanner getScanner(Collection<Range<Token>> ranges, RateLimiter limiter)
{
// We want to avoid allocating a SSTableScanner if the range don't overlap the sstable (#5249)
List<Pair<Long, Long>> positions = getPositionsForRanges(Range.normalize(ranges));
if (positions.isEmpty())
return new EmptyCompactionScanner(getFilename());
else
return new BigTableScanner(this, ranges, limiter);
}
/**
* @param key The key to apply as the rhs to the given Operator. A 'fake' key is allowed to
* allow key selection by token bounds but only if op != * EQ
* @param op The Operator defining matching keys: the nearest key to the target matching the operator wins.
* @param updateCacheAndStats true if updating stats and cache
* @return The index entry corresponding to the key, or null if the key is not present
*/
public RowIndexEntry getPosition(RowPosition key, Operator op, boolean updateCacheAndStats)
{
// first, check bloom filter
if (op == Operator.EQ)
{
assert key instanceof DecoratedKey; // EQ only make sense if the key is a valid row key
if (!bf.isPresent(((DecoratedKey)key).getKey()))
{
Tracing.trace("Bloom filter allows skipping sstable {}", descriptor.generation);
return null;
}
}
// next, the key cache (only make sense for valid row key)
if ((op == Operator.EQ || op == Operator.GE) && (key instanceof DecoratedKey))
{
DecoratedKey decoratedKey = (DecoratedKey)key;
KeyCacheKey cacheKey = new KeyCacheKey(metadata.cfId, descriptor, decoratedKey.getKey());
RowIndexEntry cachedPosition = getCachedPosition(cacheKey, updateCacheAndStats);
if (cachedPosition != null)
{
Tracing.trace("Key cache hit for sstable {}", descriptor.generation);
return cachedPosition;
}
}
// check the smallest and greatest keys in the sstable to see if it can't be present
if (first.compareTo(key) > 0 || last.compareTo(key) < 0)
{
if (op == Operator.EQ && updateCacheAndStats)
bloomFilterTracker.addFalsePositive();
if (op.apply(1) < 0)
{
Tracing.trace("Check against min and max keys allows skipping sstable {}", descriptor.generation);
return null;
}
}
int binarySearchResult = indexSummary.binarySearch(key);
long sampledPosition = getIndexScanPositionFromBinarySearchResult(binarySearchResult, indexSummary);
int sampledIndex = getIndexSummaryIndexFromBinarySearchResult(binarySearchResult);
// if we matched the -1th position, we'll start at the first position
sampledPosition = sampledPosition == -1 ? 0 : sampledPosition;
int effectiveInterval = indexSummary.getEffectiveIndexIntervalAfterIndex(sampledIndex);
// scan the on-disk index, starting at the nearest sampled position.
// The check against IndexInterval is to be exit the loop in the EQ case when the key looked for is not present
// (bloom filter false positive). But note that for non-EQ cases, we might need to check the first key of the
// next index position because the searched key can be greater the last key of the index interval checked if it
// is lesser than the first key of next interval (and in that case we must return the position of the first key
// of the next interval).
int i = 0;
Iterator<FileDataInput> segments = ifile.iterator(sampledPosition);
while (segments.hasNext() && i <= effectiveInterval)
{
FileDataInput in = segments.next();
try
{
while (!in.isEOF() && i <= effectiveInterval)
{
i++;
ByteBuffer indexKey = ByteBufferUtil.readWithShortLength(in);
boolean opSatisfied; // did we find an appropriate position for the op requested
boolean exactMatch; // is the current position an exact match for the key, suitable for caching
// Compare raw keys if possible for performance, otherwise compare decorated keys.
if (op == Operator.EQ)
{
opSatisfied = exactMatch = indexKey.equals(((DecoratedKey) key).getKey());
}
else
{
DecoratedKey indexDecoratedKey = partitioner.decorateKey(indexKey);
int comparison = indexDecoratedKey.compareTo(key);
int v = op.apply(comparison);
opSatisfied = (v == 0);
exactMatch = (comparison == 0);
if (v < 0)
{
Tracing.trace("Partition index lookup allows skipping sstable {}", descriptor.generation);
return null;
}
}
if (opSatisfied)
{
// read data position from index entry
RowIndexEntry indexEntry = rowIndexEntrySerializer.deserialize(in, descriptor.version);
if (exactMatch && updateCacheAndStats)
{
assert key instanceof DecoratedKey; // key can be == to the index key only if it's a true row key
DecoratedKey decoratedKey = (DecoratedKey)key;
if (logger.isTraceEnabled())
{
// expensive sanity check! see CASSANDRA-4687
FileDataInput fdi = dfile.getSegment(indexEntry.position);
DecoratedKey keyInDisk = partitioner.decorateKey(ByteBufferUtil.readWithShortLength(fdi));
if (!keyInDisk.equals(key))
throw new AssertionError(String.format("%s != %s in %s", keyInDisk, key, fdi.getPath()));
fdi.close();
}
// store exact match for the key
cacheKey(decoratedKey, indexEntry);
}
if (op == Operator.EQ && updateCacheAndStats)
bloomFilterTracker.addTruePositive();
Tracing.trace("Partition index with {} entries found for sstable {}", indexEntry.columnsIndex().size(), descriptor.generation);
return indexEntry;
}
RowIndexEntry.Serializer.skip(in);
}
}
catch (IOException e)
{
markSuspect();
throw new CorruptSSTableException(e, in.getPath());
}
finally
{
FileUtils.closeQuietly(in);
}
}
if (op == SSTableReader.Operator.EQ && updateCacheAndStats)
bloomFilterTracker.addFalsePositive();
Tracing.trace("Partition index lookup complete (bloom filter false positive) for sstable {}", descriptor.generation);
return null;
}
}