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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
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* distributed with this work for additional information
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* 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
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package org.apache.cassandra.index.sai.disk.v1.segment;
import java.io.IOException;
import java.util.Map;
import com.google.common.base.MoreObjects;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.apache.cassandra.db.PartitionPosition;
import org.apache.cassandra.dht.AbstractBounds;
import org.apache.cassandra.index.sai.QueryContext;
import org.apache.cassandra.index.sai.StorageAttachedIndex;
import org.apache.cassandra.index.sai.disk.PrimaryKeyMap;
import org.apache.cassandra.index.sai.disk.format.IndexComponent;
import org.apache.cassandra.index.sai.disk.v1.PerColumnIndexFiles;
import org.apache.cassandra.index.sai.disk.v1.SAICodecUtils;
import org.apache.cassandra.index.sai.iterators.KeyRangeIterator;
import org.apache.cassandra.index.sai.metrics.MulticastQueryEventListeners;
import org.apache.cassandra.index.sai.metrics.QueryEventListener;
import org.apache.cassandra.index.sai.plan.Expression;
import org.apache.cassandra.utils.bytecomparable.ByteComparable;
/**
* Executes {@link Expression}s against the trie-based terms dictionary for an individual index segment.
*/
public class LiteralIndexSegmentSearcher extends IndexSegmentSearcher
{
private static final Logger logger = LoggerFactory.getLogger(LiteralIndexSegmentSearcher.class);
private final LiteralIndexSegmentTermsReader reader;
private final QueryEventListener.TrieIndexEventListener perColumnEventListener;
LiteralIndexSegmentSearcher(PrimaryKeyMap.Factory primaryKeyMapFactory,
PerColumnIndexFiles perIndexFiles,
SegmentMetadata segmentMetadata,
StorageAttachedIndex index) throws IOException
{
super(primaryKeyMapFactory, perIndexFiles, segmentMetadata, index);
long root = metadata.getIndexRoot(IndexComponent.TERMS_DATA);
assert root >= 0;
perColumnEventListener = (QueryEventListener.TrieIndexEventListener)index.columnQueryMetrics();
Map map = metadata.componentMetadatas.get(IndexComponent.TERMS_DATA).attributes;
String footerPointerString = map.get(SAICodecUtils.FOOTER_POINTER);
long footerPointer = footerPointerString == null ? -1 : Long.parseLong(footerPointerString);
reader = new LiteralIndexSegmentTermsReader(index.identifier(), indexFiles.termsData(), indexFiles.postingLists(), root, footerPointer);
}
@Override
public long indexFileCacheSize()
{
// trie has no pre-allocated memory.
return 0;
}
@Override
public KeyRangeIterator search(Expression expression, AbstractBounds keyRange, QueryContext queryContext) throws IOException
{
if (logger.isTraceEnabled())
logger.trace(index.identifier().logMessage("Searching on expression '{}'..."), expression);
if (!expression.getIndexOperator().isEquality())
throw new IllegalArgumentException(index.identifier().logMessage("Unsupported expression: " + expression));
final ByteComparable term = ByteComparable.fixedLength(expression.lower().value.encoded);
QueryEventListener.TrieIndexEventListener listener = MulticastQueryEventListeners.of(queryContext, perColumnEventListener);
return toPrimaryKeyIterator(reader.exactMatch(term, listener, queryContext), queryContext);
}
@Override
public String toString()
{
return MoreObjects.toStringHelper(this).add("index", index).toString();
}
@Override
public void close()
{
reader.close();
}
}