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* 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.io.sstable;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Iterator;
import java.util.List;
import com.google.common.collect.AbstractIterator;
import com.google.common.util.concurrent.RateLimiter;
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.IColumnIteratorFactory;
import org.apache.cassandra.db.columniterator.LazyColumnIterator;
import org.apache.cassandra.db.columniterator.OnDiskAtomIterator;
import org.apache.cassandra.db.compaction.ICompactionScanner;
import org.apache.cassandra.dht.AbstractBounds;
import org.apache.cassandra.dht.Bounds;
import org.apache.cassandra.dht.Range;
import org.apache.cassandra.dht.Token;
import org.apache.cassandra.io.util.FileUtils;
import org.apache.cassandra.io.util.RandomAccessReader;
import org.apache.cassandra.utils.ByteBufferUtil;
public class SSTableScanner implements ICompactionScanner
{
protected final RandomAccessReader dfile;
protected final RandomAccessReader ifile;
public final SSTableReader sstable;
private final Iterator<AbstractBounds<RowPosition>> rangeIterator;
private AbstractBounds<RowPosition> currentRange;
private final DataRange dataRange;
protected Iterator<OnDiskAtomIterator> iterator;
/**
* @param sstable SSTable to scan; must not be null
* @param dataRange a single range to scan; must not be null
* @param limiter background i/o RateLimiter; may be null
*/
SSTableScanner(SSTableReader sstable, DataRange dataRange, RateLimiter limiter)
{
assert sstable != null;
this.dfile = limiter == null ? sstable.openDataReader() : sstable.openDataReader(limiter);
this.ifile = sstable.openIndexReader();
this.sstable = sstable;
this.dataRange = dataRange;
List<AbstractBounds<RowPosition>> boundsList = new ArrayList<>(2);
if (dataRange.isWrapAround() && !dataRange.stopKey().isMinimum(sstable.partitioner))
{
// split the wrapping range into two parts: 1) the part that starts at the beginning of the sstable, and
// 2) the part that comes before the wrap-around
boundsList.add(new Bounds<>(sstable.partitioner.getMinimumToken().minKeyBound(), dataRange.stopKey(), sstable.partitioner));
boundsList.add(new Bounds<>(dataRange.startKey(), sstable.partitioner.getMinimumToken().maxKeyBound(), sstable.partitioner));
}
else
{
boundsList.add(new Bounds<>(dataRange.startKey(), dataRange.stopKey(), sstable.partitioner));
}
this.rangeIterator = boundsList.iterator();
}
/**
* @param sstable SSTable to scan; must not be null
* @param tokenRanges A set of token ranges to scan
* @param limiter background i/o RateLimiter; may be null
*/
SSTableScanner(SSTableReader sstable, Collection<Range<Token>> tokenRanges, RateLimiter limiter)
{
assert sstable != null;
this.dfile = limiter == null ? sstable.openDataReader() : sstable.openDataReader(limiter);
this.ifile = sstable.openIndexReader();
this.sstable = sstable;
this.dataRange = null;
List<Range<Token>> normalized = Range.normalize(tokenRanges);
List<AbstractBounds<RowPosition>> boundsList = new ArrayList<>(normalized.size());
for (Range<Token> range : normalized)
boundsList.add(new Range<RowPosition>(range.left.maxKeyBound(sstable.partitioner),
range.right.maxKeyBound(sstable.partitioner),
sstable.partitioner));
this.rangeIterator = boundsList.iterator();
}
private void seekToCurrentRangeStart()
{
if (currentRange.left.isMinimum(sstable.partitioner))
return;
long indexPosition = sstable.getIndexScanPosition(currentRange.left);
// -1 means the key is before everything in the sstable. So just start from the beginning.
if (indexPosition == -1)
{
// Note: this method shouldn't assume we're at the start of the sstable already (see #6638) and
// the seeks are no-op anyway if we are.
ifile.seek(0);
dfile.seek(0);
return;
}
ifile.seek(indexPosition);
try
{
while (!ifile.isEOF())
{
indexPosition = ifile.getFilePointer();
DecoratedKey indexDecoratedKey = sstable.partitioner.decorateKey(ByteBufferUtil.readWithShortLength(ifile));
int comparison = indexDecoratedKey.compareTo(currentRange.left);
// because our range start may be inclusive or exclusive, we need to also contains()
// instead of just checking (comparison >= 0)
if (comparison > 0 || currentRange.contains(indexDecoratedKey))
{
// Found, just read the dataPosition and seek into index and data files
long dataPosition = ifile.readLong();
ifile.seek(indexPosition);
dfile.seek(dataPosition);
break;
}
else
{
RowIndexEntry.serializer.skip(ifile);
}
}
}
catch (IOException e)
{
sstable.markSuspect();
throw new CorruptSSTableException(e, sstable.getFilename());
}
}
public void close() throws IOException
{
FileUtils.close(dfile, ifile);
}
public long getLengthInBytes()
{
return dfile.length();
}
public long getCurrentPosition()
{
return dfile.getFilePointer();
}
public String getBackingFiles()
{
return sstable.toString();
}
public boolean hasNext()
{
if (iterator == null)
iterator = createIterator();
return iterator.hasNext();
}
public OnDiskAtomIterator next()
{
if (iterator == null)
iterator = createIterator();
return iterator.next();
}
public void remove()
{
throw new UnsupportedOperationException();
}
private Iterator<OnDiskAtomIterator> createIterator()
{
return new KeyScanningIterator();
}
protected class KeyScanningIterator extends AbstractIterator<OnDiskAtomIterator>
{
private DecoratedKey nextKey;
private RowIndexEntry nextEntry;
private DecoratedKey currentKey;
private RowIndexEntry currentEntry;
protected OnDiskAtomIterator computeNext()
{
try
{
if (nextEntry == null)
{
do
{
// we're starting the first range or we just passed the end of the previous range
if (!rangeIterator.hasNext())
return endOfData();
currentRange = rangeIterator.next();
seekToCurrentRangeStart();
if (ifile.isEOF())
return endOfData();
currentKey = sstable.partitioner.decorateKey(ByteBufferUtil.readWithShortLength(ifile));
currentEntry = RowIndexEntry.serializer.deserialize(ifile, sstable.descriptor.version);
} while (!currentRange.contains(currentKey));
}
else
{
// we're in the middle of a range
currentKey = nextKey;
currentEntry = nextEntry;
}
long readEnd;
if (ifile.isEOF())
{
nextEntry = null;
nextKey = null;
readEnd = dfile.length();
}
else
{
// we need the position of the start of the next key, regardless of whether it falls in the current range
nextKey = sstable.partitioner.decorateKey(ByteBufferUtil.readWithShortLength(ifile));
nextEntry = RowIndexEntry.serializer.deserialize(ifile, sstable.descriptor.version);
readEnd = nextEntry.position;
if (!currentRange.contains(nextKey))
{
nextKey = null;
nextEntry = null;
}
}
if (dataRange == null || dataRange.selectsFullRowFor(currentKey.key))
{
dfile.seek(currentEntry.position);
ByteBufferUtil.readWithShortLength(dfile); // key
if (sstable.descriptor.version.hasRowSizeAndColumnCount)
dfile.readLong();
long dataSize = readEnd - dfile.getFilePointer();
return new SSTableIdentityIterator(sstable, dfile, currentKey, dataSize);
}
return new LazyColumnIterator(currentKey, new IColumnIteratorFactory()
{
public OnDiskAtomIterator create()
{
return dataRange.columnFilter(currentKey.key).getSSTableColumnIterator(sstable, dfile, currentKey, currentEntry);
}
});
}
catch (CorruptSSTableException | IOException e)
{
sstable.markSuspect();
throw new CorruptSSTableException(e, sstable.getFilename());
}
}
}
@Override
public String toString()
{
return getClass().getSimpleName() + "(" +
"dfile=" + dfile +
" ifile=" + ifile +
" sstable=" + sstable +
")";
}
}