package org.apache.lucene.index;
/**
* 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.
*/
import java.io.IOException;
import java.io.PrintStream;
import java.util.List;
import java.util.ArrayList;
import java.util.Date;
import java.util.Comparator;
import java.util.Collections;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.concurrent.atomic.AtomicLong;
import org.apache.lucene.index.IndexReader.AtomicReaderContext;
import org.apache.lucene.search.IndexSearcher;
import org.apache.lucene.search.Query;
import org.apache.lucene.search.Scorer;
import org.apache.lucene.search.Weight;
/* Tracks the stream of {@link BuffereDeletes}.
* When DocumensWriter flushes, its buffered
* deletes are appended to this stream. We later
* apply these deletes (resolve them to the actual
* docIDs, per segment) when a merge is started
* (only to the to-be-merged segments). We
* also apply to all segments when NRT reader is pulled,
* commit/close is called, or when too many deletes are
* buffered and must be flushed (by RAM usage or by count).
*
* Each packet is assigned a generation, and each flushed or
* merged segment is also assigned a generation, so we can
* track which BufferedDeletes packets to apply to any given
* segment. */
class BufferedDeletesStream {
// TODO: maybe linked list?
private final List<FrozenBufferedDeletes> deletes = new ArrayList<FrozenBufferedDeletes>();
// Starts at 1 so that SegmentInfos that have never had
// deletes applied (whose bufferedDelGen defaults to 0)
// will be correct:
private long nextGen = 1;
// used only by assert
private Term lastDeleteTerm;
private PrintStream infoStream;
private final AtomicLong bytesUsed = new AtomicLong();
private final AtomicInteger numTerms = new AtomicInteger();
private final int messageID;
public BufferedDeletesStream(int messageID) {
this.messageID = messageID;
}
private synchronized void message(String message) {
if (infoStream != null) {
infoStream.println("BD " + messageID + " [" + new Date() + "; " + Thread.currentThread().getName() + "]: " + message);
}
}
public synchronized void setInfoStream(PrintStream infoStream) {
this.infoStream = infoStream;
}
// Appends a new packet of buffered deletes to the stream,
// setting its generation:
public synchronized void push(FrozenBufferedDeletes packet) {
assert packet.any();
assert checkDeleteStats();
assert packet.gen < nextGen;
deletes.add(packet);
numTerms.addAndGet(packet.numTermDeletes);
bytesUsed.addAndGet(packet.bytesUsed);
if (infoStream != null) {
message("push deletes " + packet + " delGen=" + packet.gen + " packetCount=" + deletes.size());
}
assert checkDeleteStats();
}
public synchronized void clear() {
deletes.clear();
nextGen = 1;
numTerms.set(0);
bytesUsed.set(0);
}
public boolean any() {
return bytesUsed.get() != 0;
}
public int numTerms() {
return numTerms.get();
}
public long bytesUsed() {
return bytesUsed.get();
}
public static class ApplyDeletesResult {
// True if any actual deletes took place:
public final boolean anyDeletes;
// Current gen, for the merged segment:
public final long gen;
// If non-null, contains segments that are 100% deleted
public final SegmentInfos allDeleted;
ApplyDeletesResult(boolean anyDeletes, long gen, SegmentInfos allDeleted) {
this.anyDeletes = anyDeletes;
this.gen = gen;
this.allDeleted = allDeleted;
}
}
// Sorts SegmentInfos from smallest to biggest bufferedDelGen:
private static final Comparator<SegmentInfo> sortByDelGen = new Comparator<SegmentInfo>() {
// @Override -- not until Java 1.6
public int compare(SegmentInfo si1, SegmentInfo si2) {
final long cmp = si1.getBufferedDeletesGen() - si2.getBufferedDeletesGen();
if (cmp > 0) {
return 1;
} else if (cmp < 0) {
return -1;
} else {
return 0;
}
}
@Override
public boolean equals(Object other) {
return sortByDelGen == other;
}
};
/** Resolves the buffered deleted Term/Query/docIDs, into
* actual deleted docIDs in the deletedDocs BitVector for
* each SegmentReader. */
public synchronized ApplyDeletesResult applyDeletes(IndexWriter.ReaderPool readerPool, SegmentInfos infos) throws IOException {
final long t0 = System.currentTimeMillis();
if (infos.size() == 0) {
return new ApplyDeletesResult(false, nextGen++, null);
}
assert checkDeleteStats();
if (!any()) {
message("applyDeletes: no deletes; skipping");
return new ApplyDeletesResult(false, nextGen++, null);
}
if (infoStream != null) {
message("applyDeletes: infos=" + infos + " packetCount=" + deletes.size());
}
SegmentInfos infos2 = new SegmentInfos();
infos2.addAll(infos);
Collections.sort(infos2, sortByDelGen);
BufferedDeletes coalescedDeletes = null;
boolean anyNewDeletes = false;
int infosIDX = infos2.size()-1;
int delIDX = deletes.size()-1;
SegmentInfos allDeleted = null;
while (infosIDX >= 0) {
//System.out.println("BD: cycle delIDX=" + delIDX + " infoIDX=" + infosIDX);
final FrozenBufferedDeletes packet = delIDX >= 0 ? deletes.get(delIDX) : null;
final SegmentInfo info = infos2.get(infosIDX);
final long segGen = info.getBufferedDeletesGen();
if (packet != null && segGen < packet.gen) {
//System.out.println(" coalesce");
if (coalescedDeletes == null) {
coalescedDeletes = new BufferedDeletes(true);
}
coalescedDeletes.update(packet);
delIDX--;
} else if (packet != null && segGen == packet.gen) {
//System.out.println(" eq");
// Lock order: IW -> BD -> RP
assert readerPool.infoIsLive(info);
SegmentReader reader = readerPool.get(info, false);
int delCount = 0;
final boolean segAllDeletes;
try {
if (coalescedDeletes != null) {
//System.out.println(" del coalesced");
delCount += applyTermDeletes(coalescedDeletes.termsIterable(), reader);
delCount += applyQueryDeletes(coalescedDeletes.queriesIterable(), reader);
}
//System.out.println(" del exact");
// Don't delete by Term here; DocumentsWriter
// already did that on flush:
delCount += applyQueryDeletes(packet.queriesIterable(), reader);
segAllDeletes = reader.numDocs() == 0;
} finally {
readerPool.release(reader);
}
anyNewDeletes |= delCount > 0;
if (segAllDeletes) {
if (allDeleted == null) {
allDeleted = new SegmentInfos();
}
allDeleted.add(info);
}
if (infoStream != null) {
message("seg=" + info + " segGen=" + segGen + " segDeletes=[" + packet + "]; coalesced deletes=[" + (coalescedDeletes == null ? "null" : coalescedDeletes) + "] delCount=" + delCount + (segAllDeletes ? " 100% deleted" : ""));
}
if (coalescedDeletes == null) {
coalescedDeletes = new BufferedDeletes(true);
}
coalescedDeletes.update(packet);
delIDX--;
infosIDX--;
info.setBufferedDeletesGen(nextGen);
} else {
//System.out.println(" gt");
if (coalescedDeletes != null) {
// Lock order: IW -> BD -> RP
assert readerPool.infoIsLive(info);
SegmentReader reader = readerPool.get(info, false);
int delCount = 0;
final boolean segAllDeletes;
try {
delCount += applyTermDeletes(coalescedDeletes.termsIterable(), reader);
delCount += applyQueryDeletes(coalescedDeletes.queriesIterable(), reader);
segAllDeletes = reader.numDocs() == 0;
} finally {
readerPool.release(reader);
}
anyNewDeletes |= delCount > 0;
if (segAllDeletes) {
if (allDeleted == null) {
allDeleted = new SegmentInfos();
}
allDeleted.add(info);
}
if (infoStream != null) {
message("seg=" + info + " segGen=" + segGen + " coalesced deletes=[" + (coalescedDeletes == null ? "null" : coalescedDeletes) + "] delCount=" + delCount + (segAllDeletes ? " 100% deleted" : ""));
}
}
info.setBufferedDeletesGen(nextGen);
infosIDX--;
}
}
assert checkDeleteStats();
if (infoStream != null) {
message("applyDeletes took " + (System.currentTimeMillis()-t0) + " msec");
}
// assert infos != segmentInfos || !any() : "infos=" + infos + " segmentInfos=" + segmentInfos + " any=" + any;
return new ApplyDeletesResult(anyNewDeletes, nextGen++, allDeleted);
}
public synchronized long getNextGen() {
return nextGen++;
}
// Lock order IW -> BD
/* Removes any BufferedDeletes that we no longer need to
* store because all segments in the index have had the
* deletes applied. */
public synchronized void prune(SegmentInfos segmentInfos) {
assert checkDeleteStats();
long minGen = Long.MAX_VALUE;
for(SegmentInfo info : segmentInfos) {
minGen = Math.min(info.getBufferedDeletesGen(), minGen);
}
if (infoStream != null) {
message("prune sis=" + segmentInfos + " minGen=" + minGen + " packetCount=" + deletes.size());
}
final int limit = deletes.size();
for(int delIDX=0;delIDX<limit;delIDX++) {
if (deletes.get(delIDX).gen >= minGen) {
prune(delIDX);
assert checkDeleteStats();
return;
}
}
// All deletes pruned
prune(limit);
assert !any();
assert checkDeleteStats();
}
private synchronized void prune(int count) {
if (count > 0) {
if (infoStream != null) {
message("pruneDeletes: prune " + count + " packets; " + (deletes.size() - count) + " packets remain");
}
for(int delIDX=0;delIDX<count;delIDX++) {
final FrozenBufferedDeletes packet = deletes.get(delIDX);
numTerms.addAndGet(-packet.numTermDeletes);
assert numTerms.get() >= 0;
bytesUsed.addAndGet(-packet.bytesUsed);
assert bytesUsed.get() >= 0;
}
deletes.subList(0, count).clear();
}
}
// Delete by Term
private synchronized long applyTermDeletes(Iterable<Term> termsIter, SegmentReader reader) throws IOException {
long delCount = 0;
Fields fields = reader.fields();
if (fields == null) {
// This reader has no postings
return 0;
}
TermsEnum termsEnum = null;
String currentField = null;
DocsEnum docs = null;
assert checkDeleteTerm(null);
for (Term term : termsIter) {
// Since we visit terms sorted, we gain performance
// by re-using the same TermsEnum and seeking only
// forwards
if (term.field() != currentField) {
assert currentField == null || currentField.compareTo(term.field()) < 0;
currentField = term.field();
Terms terms = fields.terms(currentField);
if (terms != null) {
termsEnum = terms.iterator();
} else {
termsEnum = null;
}
}
if (termsEnum == null) {
continue;
}
assert checkDeleteTerm(term);
// System.out.println(" term=" + term);
if (termsEnum.seek(term.bytes(), false) == TermsEnum.SeekStatus.FOUND) {
DocsEnum docsEnum = termsEnum.docs(reader.getDeletedDocs(), docs);
if (docsEnum != null) {
while (true) {
final int docID = docsEnum.nextDoc();
if (docID == DocsEnum.NO_MORE_DOCS) {
break;
}
reader.deleteDocument(docID);
// TODO: we could/should change
// reader.deleteDocument to return boolean
// true if it did in fact delete, because here
// we could be deleting an already-deleted doc
// which makes this an upper bound:
delCount++;
}
}
}
}
return delCount;
}
public static class QueryAndLimit {
public final Query query;
public final int limit;
public QueryAndLimit(Query query, int limit) {
this.query = query;
this.limit = limit;
}
}
// Delete by query
private synchronized long applyQueryDeletes(Iterable<QueryAndLimit> queriesIter, SegmentReader reader) throws IOException {
long delCount = 0;
IndexSearcher searcher = new IndexSearcher(reader);
assert searcher.getTopReaderContext().isAtomic;
final AtomicReaderContext readerContext = (AtomicReaderContext) searcher.getTopReaderContext();
try {
for (QueryAndLimit ent : queriesIter) {
Query query = ent.query;
int limit = ent.limit;
Weight weight = query.weight(searcher);
Scorer scorer = weight.scorer(readerContext, Weight.ScorerContext.def());
if (scorer != null) {
while(true) {
int doc = scorer.nextDoc();
if (doc >= limit)
break;
reader.deleteDocument(doc);
// TODO: we could/should change
// reader.deleteDocument to return boolean
// true if it did in fact delete, because here
// we could be deleting an already-deleted doc
// which makes this an upper bound:
delCount++;
}
}
}
} finally {
searcher.close();
}
return delCount;
}
// used only by assert
private boolean checkDeleteTerm(Term term) {
if (term != null) {
assert lastDeleteTerm == null || term.compareTo(lastDeleteTerm) > 0: "lastTerm=" + lastDeleteTerm + " vs term=" + term;
}
lastDeleteTerm = term;
return true;
}
// only for assert
private boolean checkDeleteStats() {
int numTerms2 = 0;
long bytesUsed2 = 0;
for(FrozenBufferedDeletes packet : deletes) {
numTerms2 += packet.numTermDeletes;
bytesUsed2 += packet.bytesUsed;
}
assert numTerms2 == numTerms.get(): "numTerms2=" + numTerms2 + " vs " + numTerms.get();
assert bytesUsed2 == bytesUsed.get(): "bytesUsed2=" + bytesUsed2 + " vs " + bytesUsed;
return true;
}
}