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* Licensed to Elasticsearch under one or more contributor
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* this work for additional information regarding copyright
* ownership. Elasticsearch 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
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package org.elasticsearch.index.fielddata.ordinals;
import org.apache.lucene.index.DocValues;
import org.apache.lucene.index.SortedSetDocValues;
import org.apache.lucene.util.Accountable;
import org.apache.lucene.util.Accountables;
import org.apache.lucene.util.BytesRef;
import org.apache.lucene.util.LongsRef;
import org.apache.lucene.util.packed.PackedInts;
import org.apache.lucene.util.packed.PackedLongValues;
import org.elasticsearch.index.fielddata.AbstractSortedDocValues;
import org.elasticsearch.index.fielddata.AbstractSortedSetDocValues;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.List;
/**
* {@link Ordinals} implementation which is efficient at storing field data ordinals for multi-valued or sparse fields.
*/
public class MultiOrdinals extends Ordinals {
private static final int OFFSETS_PAGE_SIZE = 1024;
/**
* Return true if this impl is going to be smaller than {@link SinglePackedOrdinals} by at least 20%.
*/
public static boolean significantlySmallerThanSinglePackedOrdinals(int maxDoc, int numDocsWithValue, long numOrds, float acceptableOverheadRatio) {
int bitsPerOrd = PackedInts.bitsRequired(numOrds);
bitsPerOrd = PackedInts.fastestFormatAndBits(numDocsWithValue, bitsPerOrd, acceptableOverheadRatio).bitsPerValue;
// Compute the worst-case number of bits per value for offsets in the worst case, eg. if no docs have a value at the
// beginning of the block and all docs have one at the end of the block
final float avgValuesPerDoc = (float) numDocsWithValue / maxDoc;
final int maxDelta = (int) Math.ceil(OFFSETS_PAGE_SIZE * (1 - avgValuesPerDoc) * avgValuesPerDoc);
int bitsPerOffset = PackedInts.bitsRequired(maxDelta) + 1; // +1 because of the sign
bitsPerOffset = PackedInts.fastestFormatAndBits(maxDoc, bitsPerOffset, acceptableOverheadRatio).bitsPerValue;
final long expectedMultiSizeInBytes = (long) numDocsWithValue * bitsPerOrd + (long) maxDoc * bitsPerOffset;
final long expectedSingleSizeInBytes = (long) maxDoc * bitsPerOrd;
return expectedMultiSizeInBytes < 0.8f * expectedSingleSizeInBytes;
}
private final boolean multiValued;
private final long valueCount;
private final PackedLongValues endOffsets;
private final PackedLongValues ords;
public MultiOrdinals(OrdinalsBuilder builder, float acceptableOverheadRatio) {
multiValued = builder.getNumMultiValuesDocs() > 0;
valueCount = builder.getValueCount();
PackedLongValues.Builder endOffsetsBuilder = PackedLongValues.monotonicBuilder(OFFSETS_PAGE_SIZE, acceptableOverheadRatio);
PackedLongValues.Builder ordsBuilder = PackedLongValues.packedBuilder(OFFSETS_PAGE_SIZE, acceptableOverheadRatio);
long lastEndOffset = 0;
for (int i = 0; i < builder.maxDoc(); ++i) {
final LongsRef docOrds = builder.docOrds(i);
final long endOffset = lastEndOffset + docOrds.length;
endOffsetsBuilder.add(endOffset);
for (int j = 0; j < docOrds.length; ++j) {
ordsBuilder.add(docOrds.longs[docOrds.offset + j]);
}
lastEndOffset = endOffset;
}
endOffsets = endOffsetsBuilder.build();
ords = ordsBuilder.build();
assert endOffsets.size() == builder.maxDoc();
assert ords.size() == builder.getTotalNumOrds() : ords.size() + " != " + builder.getTotalNumOrds();
}
@Override
public long ramBytesUsed() {
return endOffsets.ramBytesUsed() + ords.ramBytesUsed();
}
@Override
public Collection<Accountable> getChildResources() {
List<Accountable> resources = new ArrayList<>();
resources.add(Accountables.namedAccountable("offsets", endOffsets));
resources.add(Accountables.namedAccountable("ordinals", ords));
return Collections.unmodifiableCollection(resources);
}
@Override
public SortedSetDocValues ordinals(ValuesHolder values) {
if (multiValued) {
return new MultiDocs(this, values);
} else {
return (SortedSetDocValues) DocValues.singleton(new SingleDocs(this, values));
}
}
private static class SingleDocs extends AbstractSortedDocValues {
private final int valueCount;
private final PackedLongValues endOffsets;
private final PackedLongValues ords;
private final ValuesHolder values;
private int currentDoc = -1;
private long currentStartOffset;
private long currentEndOffset;
SingleDocs(MultiOrdinals ordinals, ValuesHolder values) {
this.valueCount = (int) ordinals.valueCount;
this.endOffsets = ordinals.endOffsets;
this.ords = ordinals.ords;
this.values = values;
}
@Override
public int ordValue() {
return (int) ords.get(currentStartOffset);
}
@Override
public boolean advanceExact(int docId) throws IOException {
currentDoc = docId;
currentStartOffset = docId != 0 ? endOffsets.get(docId - 1) : 0;
currentEndOffset = endOffsets.get(docId);
return currentStartOffset != currentEndOffset;
}
@Override
public int docID() {
return currentDoc;
}
@Override
public BytesRef lookupOrd(int ord) {
return values.lookupOrd(ord);
}
@Override
public int getValueCount() {
return valueCount;
}
}
private static class MultiDocs extends AbstractSortedSetDocValues {
private final long valueCount;
private final PackedLongValues endOffsets;
private final PackedLongValues ords;
private final ValuesHolder values;
private long currentOffset;
private long currentEndOffset;
MultiDocs(MultiOrdinals ordinals, ValuesHolder values) {
this.valueCount = ordinals.valueCount;
this.endOffsets = ordinals.endOffsets;
this.ords = ordinals.ords;
this.values = values;
}
@Override
public long getValueCount() {
return valueCount;
}
@Override
public boolean advanceExact(int docId) throws IOException {
currentOffset = docId != 0 ? endOffsets.get(docId - 1) : 0;
currentEndOffset = endOffsets.get(docId);
return currentOffset != currentEndOffset;
}
@Override
public long nextOrd() throws IOException {
if (currentOffset == currentEndOffset) {
return SortedSetDocValues.NO_MORE_ORDS;
} else {
return ords.get(currentOffset++);
}
}
@Override
public BytesRef lookupOrd(long ord) {
return values.lookupOrd(ord);
}
}
}