forked from apache/lucene
-
Notifications
You must be signed in to change notification settings - Fork 0
Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
Use the new
loadIntoBitSet API to speed up dense conjunctions. (apa…
…che#14080) Now that loading doc IDs into a bit set is much more efficient thanks to auto-vectorization, it has become tempting to evaluate dense conjunctions by and-ing bit sets.
- Loading branch information
Showing
7 changed files
with
484 additions
and
10 deletions.
There are no files selected for viewing
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
193 changes: 193 additions & 0 deletions
193
lucene/core/src/java/org/apache/lucene/search/DenseConjunctionBulkScorer.java
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,193 @@ | ||
| /* | ||
| * 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.search; | ||
|
|
||
| import java.io.IOException; | ||
| import java.util.ArrayList; | ||
| import java.util.Comparator; | ||
| import java.util.List; | ||
| import org.apache.lucene.util.Bits; | ||
| import org.apache.lucene.util.FixedBitSet; | ||
|
|
||
| /** | ||
| * BulkScorer implementation of {@link ConjunctionScorer} that is specialized for dense clauses. | ||
| * Whenever sensible, it intersects clauses by loading their matches into a bit set and computing | ||
| * the intersection of clauses by and-ing these bit sets. | ||
| */ | ||
| final class DenseConjunctionBulkScorer extends BulkScorer { | ||
|
|
||
| // Use a small-ish window size to make sure that we can take advantage of gaps in the postings of | ||
| // clauses that are not leading iteration. | ||
| static final int WINDOW_SIZE = 4096; | ||
| // Only use bit sets to compute the intersection if more than 1/32th of the docs are expected to | ||
| // match. Experiments suggested that values that are a bit higher than this would work better, but | ||
| // we're erring on the conservative side. | ||
| static final int DENSITY_THRESHOLD_INVERSE = Long.SIZE / 2; | ||
|
|
||
| private final DocIdSetIterator lead; | ||
| private final List<DocIdSetIterator> others; | ||
|
|
||
| private final FixedBitSet windowMatches = new FixedBitSet(WINDOW_SIZE); | ||
| private final FixedBitSet clauseWindowMatches = new FixedBitSet(WINDOW_SIZE); | ||
| private final DocIdStreamView docIdStreamView = new DocIdStreamView(); | ||
|
|
||
| DenseConjunctionBulkScorer(List<DocIdSetIterator> iterators) { | ||
| if (iterators.size() <= 1) { | ||
| throw new IllegalArgumentException("Expected 2 or more clauses, got " + iterators.size()); | ||
| } | ||
| iterators = new ArrayList<>(iterators); | ||
| iterators.sort(Comparator.comparingLong(DocIdSetIterator::cost)); | ||
| lead = iterators.get(0); | ||
| others = List.copyOf(iterators.subList(1, iterators.size())); | ||
| } | ||
|
|
||
| @Override | ||
| public int score(LeafCollector collector, Bits acceptDocs, int min, int max) throws IOException { | ||
| for (DocIdSetIterator it : others) { | ||
| min = Math.max(min, it.docID()); | ||
| } | ||
|
|
||
| if (lead.docID() < min) { | ||
| lead.advance(min); | ||
| } | ||
|
|
||
| if (lead.docID() >= max) { | ||
| return lead.docID(); | ||
| } | ||
|
|
||
| List<DocIdSetIterator> otherIterators = this.others; | ||
| DocIdSetIterator collectorIterator = collector.competitiveIterator(); | ||
| if (collectorIterator != null) { | ||
| otherIterators = new ArrayList<>(otherIterators); | ||
| otherIterators.add(collectorIterator); | ||
| } | ||
|
|
||
| final DocIdSetIterator[] others = otherIterators.toArray(DocIdSetIterator[]::new); | ||
|
|
||
| int windowMax; | ||
| do { | ||
| windowMax = (int) Math.min(max, (long) lead.docID() + WINDOW_SIZE); | ||
| scoreWindowUsingBitSet(collector, acceptDocs, others, windowMax); | ||
| } while (windowMax < max); | ||
|
|
||
| return lead.docID(); | ||
| } | ||
|
|
||
| private static int advance(FixedBitSet set, int i) { | ||
| if (i >= WINDOW_SIZE) { | ||
| return DocIdSetIterator.NO_MORE_DOCS; | ||
| } else { | ||
| return set.nextSetBit(i); | ||
| } | ||
| } | ||
|
|
||
| private void scoreWindowUsingBitSet( | ||
| LeafCollector collector, Bits acceptDocs, DocIdSetIterator[] others, int max) | ||
| throws IOException { | ||
| assert windowMatches.scanIsEmpty(); | ||
| assert clauseWindowMatches.scanIsEmpty(); | ||
|
|
||
| int offset = lead.docID(); | ||
| lead.intoBitSet(acceptDocs, max, windowMatches, offset); | ||
|
|
||
| int upTo = 0; | ||
| for (; | ||
| upTo < others.length | ||
| && windowMatches.cardinality() >= WINDOW_SIZE / DENSITY_THRESHOLD_INVERSE; | ||
| upTo++) { | ||
| DocIdSetIterator other = others[upTo]; | ||
| if (other.docID() < offset) { | ||
| other.advance(offset); | ||
| } | ||
| // No need to apply acceptDocs on other clauses since we already applied live docs on the | ||
| // leading clause. | ||
| other.intoBitSet(null, max, clauseWindowMatches, offset); | ||
| windowMatches.and(clauseWindowMatches); | ||
| clauseWindowMatches.clear(); | ||
| } | ||
|
|
||
| if (upTo < others.length) { | ||
| // If the leading clause is sparse on this doc ID range or if the intersection became sparse | ||
| // after applying a few clauses, we finish evaluating the intersection using the traditional | ||
| // leap-frog approach. This proved important with a query such as "+secretary +of +state" on | ||
| // wikibigall, where the intersection becomes sparse after intersecting "secretary" and | ||
| // "state". | ||
| advanceHead: | ||
| for (int windowMatch = windowMatches.nextSetBit(0); | ||
| windowMatch != DocIdSetIterator.NO_MORE_DOCS; ) { | ||
| int doc = offset + windowMatch; | ||
| for (int i = upTo; i < others.length; ++i) { | ||
| DocIdSetIterator other = others[i]; | ||
| int otherDoc = other.docID(); | ||
| if (otherDoc < doc) { | ||
| otherDoc = other.advance(doc); | ||
| } | ||
| if (doc != otherDoc) { | ||
| int clearUpTo = Math.min(WINDOW_SIZE, otherDoc - offset); | ||
| windowMatches.clear(windowMatch, clearUpTo); | ||
| windowMatch = advance(windowMatches, clearUpTo); | ||
| continue advanceHead; | ||
| } | ||
| } | ||
| windowMatch = advance(windowMatches, windowMatch + 1); | ||
| } | ||
| } | ||
|
|
||
| docIdStreamView.offset = offset; | ||
| collector.collect(docIdStreamView); | ||
| windowMatches.clear(); | ||
|
|
||
| // If another clause is more advanced than lead1 then advance lead1, it's important to take | ||
| // advantage of large gaps in the postings lists of other clauses. | ||
| int maxOtherDocID = -1; | ||
| for (DocIdSetIterator other : others) { | ||
| maxOtherDocID = Math.max(maxOtherDocID, other.docID()); | ||
| } | ||
| if (lead.docID() < maxOtherDocID) { | ||
| lead.advance(maxOtherDocID); | ||
| } | ||
| } | ||
|
|
||
| @Override | ||
| public long cost() { | ||
| return lead.cost(); | ||
| } | ||
|
|
||
| final class DocIdStreamView extends DocIdStream { | ||
|
|
||
| int offset; | ||
|
|
||
| @Override | ||
| public void forEach(CheckedIntConsumer<IOException> consumer) throws IOException { | ||
| int offset = this.offset; | ||
| long[] bitArray = windowMatches.getBits(); | ||
| for (int idx = 0; idx < bitArray.length; idx++) { | ||
| long bits = bitArray[idx]; | ||
| while (bits != 0L) { | ||
| int ntz = Long.numberOfTrailingZeros(bits); | ||
| consumer.accept(offset + ((idx << 6) | ntz)); | ||
| bits ^= 1L << ntz; | ||
| } | ||
| } | ||
| } | ||
|
|
||
| @Override | ||
| public int count() throws IOException { | ||
| return windowMatches.cardinality(); | ||
| } | ||
| } | ||
| } |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Oops, something went wrong.