org.apache.lucene.index.SegmentReader Maven / Gradle / Ivy
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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.lucene.index;
import java.io.IOException;
import java.util.Collections;
import org.apache.lucene.codecs.Codec;
import org.apache.lucene.codecs.DocValuesProducer;
import org.apache.lucene.codecs.FieldInfosFormat;
import org.apache.lucene.codecs.FieldsProducer;
import org.apache.lucene.codecs.NormsProducer;
import org.apache.lucene.codecs.PointsReader;
import org.apache.lucene.codecs.StoredFieldsReader;
import org.apache.lucene.codecs.TermVectorsReader;
import org.apache.lucene.search.Sort;
import org.apache.lucene.store.Directory;
import org.apache.lucene.store.IOContext;
import org.apache.lucene.util.Bits;
/**
* IndexReader implementation over a single segment.
*
* Instances pointing to the same segment (but with different deletes, etc)
* may share the same core data.
* @lucene.experimental
*/
public final class SegmentReader extends CodecReader {
private final SegmentCommitInfo si;
private final Bits liveDocs;
// Normally set to si.maxDoc - si.delDocCount, unless we
// were created as an NRT reader from IW, in which case IW
// tells us the number of live docs:
private final int numDocs;
final SegmentCoreReaders core;
final SegmentDocValues segDocValues;
/** True if we are holding RAM only liveDocs or DV updates, i.e. the SegmentCommitInfo delGen doesn't match our liveDocs. */
final boolean isNRT;
final DocValuesProducer docValuesProducer;
final FieldInfos fieldInfos;
/**
* Constructs a new SegmentReader with a new core.
* @throws CorruptIndexException if the index is corrupt
* @throws IOException if there is a low-level IO error
*/
// TODO: why is this public?
public SegmentReader(SegmentCommitInfo si, IOContext context) throws IOException {
this.si = si;
// We pull liveDocs/DV updates from disk:
this.isNRT = false;
core = new SegmentCoreReaders(si.info.dir, si, context);
segDocValues = new SegmentDocValues();
boolean success = false;
final Codec codec = si.info.getCodec();
try {
if (si.hasDeletions()) {
// NOTE: the bitvector is stored using the regular directory, not cfs
liveDocs = codec.liveDocsFormat().readLiveDocs(directory(), si, IOContext.READONCE);
} else {
assert si.getDelCount() == 0;
liveDocs = null;
}
numDocs = si.info.maxDoc() - si.getDelCount();
fieldInfos = initFieldInfos();
docValuesProducer = initDocValuesProducer();
success = true;
} finally {
// With lock-less commits, it's entirely possible (and
// fine) to hit a FileNotFound exception above. In
// this case, we want to explicitly close any subset
// of things that were opened so that we don't have to
// wait for a GC to do so.
if (!success) {
doClose();
}
}
}
/** Create new SegmentReader sharing core from a previous
* SegmentReader and loading new live docs from a new
* deletes file. Used by openIfChanged. */
SegmentReader(SegmentCommitInfo si, SegmentReader sr) throws IOException {
this(si, sr,
si.hasDeletions() ? si.info.getCodec().liveDocsFormat().readLiveDocs(si.info.dir, si, IOContext.READONCE) : null,
si.info.maxDoc() - si.getDelCount(), false);
}
/** Create new SegmentReader sharing core from a previous
* SegmentReader and using the provided in-memory
* liveDocs. Used by IndexWriter to provide a new NRT
* reader */
SegmentReader(SegmentCommitInfo si, SegmentReader sr, Bits liveDocs, int numDocs) throws IOException {
this(si, sr, liveDocs, numDocs, true);
}
/** Create new SegmentReader sharing core from a previous
* SegmentReader and using the provided liveDocs, and recording
* whether those liveDocs were carried in ram (isNRT=true). */
SegmentReader(SegmentCommitInfo si, SegmentReader sr, Bits liveDocs, int numDocs, boolean isNRT) throws IOException {
if (numDocs > si.info.maxDoc()) {
throw new IllegalArgumentException("numDocs=" + numDocs + " but maxDoc=" + si.info.maxDoc());
}
if (liveDocs != null && liveDocs.length() != si.info.maxDoc()) {
throw new IllegalArgumentException("maxDoc=" + si.info.maxDoc() + " but liveDocs.size()=" + liveDocs.length());
}
this.si = si;
this.liveDocs = liveDocs;
this.isNRT = isNRT;
this.numDocs = numDocs;
this.core = sr.core;
core.incRef();
this.segDocValues = sr.segDocValues;
boolean success = false;
try {
fieldInfos = initFieldInfos();
docValuesProducer = initDocValuesProducer();
success = true;
} finally {
if (!success) {
doClose();
}
}
}
/**
* init most recent DocValues for the current commit
*/
private DocValuesProducer initDocValuesProducer() throws IOException {
final Directory dir = core.cfsReader != null ? core.cfsReader : si.info.dir;
if (!fieldInfos.hasDocValues()) {
return null;
} else if (si.hasFieldUpdates()) {
return new SegmentDocValuesProducer(si, dir, core.coreFieldInfos, fieldInfos, segDocValues);
} else {
// simple case, no DocValues updates
return segDocValues.getDocValuesProducer(-1L, si, dir, fieldInfos);
}
}
/**
* init most recent FieldInfos for the current commit
*/
private FieldInfos initFieldInfos() throws IOException {
if (!si.hasFieldUpdates()) {
return core.coreFieldInfos;
} else {
// updates always outside of CFS
FieldInfosFormat fisFormat = si.info.getCodec().fieldInfosFormat();
final String segmentSuffix = Long.toString(si.getFieldInfosGen(), Character.MAX_RADIX);
return fisFormat.read(si.info.dir, si.info, segmentSuffix, IOContext.READONCE);
}
}
@Override
public Bits getLiveDocs() {
ensureOpen();
return liveDocs;
}
@Override
protected void doClose() throws IOException {
//System.out.println("SR.close seg=" + si);
try {
core.decRef();
} finally {
try {
super.doClose();
} finally {
if (docValuesProducer instanceof SegmentDocValuesProducer) {
segDocValues.decRef(((SegmentDocValuesProducer)docValuesProducer).dvGens);
} else if (docValuesProducer != null) {
segDocValues.decRef(Collections.singletonList(-1L));
}
}
}
}
@Override
public FieldInfos getFieldInfos() {
ensureOpen();
return fieldInfos;
}
@Override
public int numDocs() {
// Don't call ensureOpen() here (it could affect performance)
return numDocs;
}
@Override
public int maxDoc() {
// Don't call ensureOpen() here (it could affect performance)
return si.info.maxDoc();
}
@Override
public TermVectorsReader getTermVectorsReader() {
ensureOpen();
return core.termVectorsLocal.get();
}
@Override
public StoredFieldsReader getFieldsReader() {
ensureOpen();
return core.fieldsReaderLocal.get();
}
@Override
public PointValues getPointValues() {
ensureOpen();
return core.pointsReader;
}
@Override
public NormsProducer getNormsReader() {
ensureOpen();
return core.normsProducer;
}
@Override
public DocValuesProducer getDocValuesReader() {
ensureOpen();
return docValuesProducer;
}
@Override
public FieldsProducer getPostingsReader() {
ensureOpen();
return core.fields;
}
@Override
public PointsReader getPointsReader() {
ensureOpen();
return core.pointsReader;
}
@Override
public String toString() {
// SegmentInfo.toString takes dir and number of
// *pending* deletions; so we reverse compute that here:
return si.toString(si.info.maxDoc() - numDocs - si.getDelCount());
}
/**
* Return the name of the segment this reader is reading.
*/
public String getSegmentName() {
return si.info.name;
}
/**
* Return the SegmentInfoPerCommit of the segment this reader is reading.
*/
public SegmentCommitInfo getSegmentInfo() {
return si;
}
/** Returns the directory this index resides in. */
public Directory directory() {
// Don't ensureOpen here -- in certain cases, when a
// cloned/reopened reader needs to commit, it may call
// this method on the closed original reader
return si.info.dir;
}
// This is necessary so that cloned SegmentReaders (which
// share the underlying postings data) will map to the
// same entry for CachingWrapperFilter. See LUCENE-1579.
@Override
public Object getCoreCacheKey() {
// NOTE: if this ever changes, be sure to fix
// SegmentCoreReader.notifyCoreClosedListeners to match!
// Today it passes "this" as its coreCacheKey:
return core;
}
@Override
public Object getCombinedCoreAndDeletesKey() {
return this;
}
@Override
public void addCoreClosedListener(CoreClosedListener listener) {
ensureOpen();
core.addCoreClosedListener(listener);
}
@Override
public void removeCoreClosedListener(CoreClosedListener listener) {
ensureOpen();
core.removeCoreClosedListener(listener);
}
@Override
public Sort getIndexSort() {
return si.info.getIndexSort();
}
}