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Use group-varint encoding for the tail of postings (#12782)
Co-authored-by: Adrien Grand <jpountz@gmail.com>
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57 changes: 57 additions & 0 deletions
57
lucene/core/src/java/org/apache/lucene/codecs/lucene99/GroupVIntReader.java
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,57 @@ | ||
| /* | ||
| * 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.codecs.lucene99; | ||
|
|
||
| import java.io.IOException; | ||
| import org.apache.lucene.store.DataInput; | ||
|
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| /** Decode integers using group-varint. */ | ||
| public class GroupVIntReader { | ||
|
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| public static void readValues(DataInput in, long[] docs, int limit) throws IOException { | ||
| int i; | ||
| for (i = 0; i <= limit - 4; i += 4) { | ||
| final int flag = in.readByte() & 0xFF; | ||
|
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| final int n1Minus1 = flag >> 6; | ||
| final int n2Minus1 = (flag >> 4) & 0x03; | ||
| final int n3Minus1 = (flag >> 2) & 0x03; | ||
| final int n4Minus1 = flag & 0x03; | ||
|
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| docs[i] = readLong(in, n1Minus1); | ||
| docs[i + 1] = readLong(in, n2Minus1); | ||
| docs[i + 2] = readLong(in, n3Minus1); | ||
| docs[i + 3] = readLong(in, n4Minus1); | ||
| } | ||
| for (; i < limit; ++i) { | ||
| docs[i] = in.readVInt(); | ||
| } | ||
| } | ||
|
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| private static long readLong(DataInput in, int numBytesMinus1) throws IOException { | ||
| switch (numBytesMinus1) { | ||
| case 0: | ||
| return in.readByte() & 0xFFL; | ||
| case 1: | ||
| return in.readShort() & 0xFFFFL; | ||
| case 2: | ||
| return (in.readShort() & 0xFFFFL) | ((in.readByte() & 0xFFL) << 16); | ||
| default: | ||
| return in.readInt() & 0xFFFFFFFFL; | ||
| } | ||
| } | ||
| } |
63 changes: 63 additions & 0 deletions
63
lucene/core/src/java/org/apache/lucene/codecs/lucene99/GroupVIntWriter.java
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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.codecs.lucene99; | ||
|
|
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| import java.io.IOException; | ||
| import org.apache.lucene.store.DataOutput; | ||
|
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| /** | ||
| * Encode integers using group-varint. It uses VInt to encode tail values that are not enough for a | ||
| * group | ||
| */ | ||
| public class GroupVIntWriter { | ||
|
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| // the maximum size of one group is 4 integers + 1 byte flag. | ||
| private byte[] bytes = new byte[17]; | ||
| private int byteOffset = 0; | ||
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| public GroupVIntWriter() {} | ||
|
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| private int encodeValue(int v) { | ||
| int lastOff = byteOffset; | ||
| do { | ||
| bytes[byteOffset++] = (byte) (v & 0xFF); | ||
| v >>>= 8; | ||
| } while (v != 0); | ||
| return byteOffset - lastOff; | ||
| } | ||
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| public void writeValues(DataOutput out, long[] values, int limit) throws IOException { | ||
| int off = 0; | ||
|
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| // encode each group | ||
| while ((limit - off) >= 4) { | ||
| byte flag = 0; | ||
| byteOffset = 1; | ||
| flag |= (encodeValue((int) values[off++]) - 1) << 6; | ||
| flag |= (encodeValue((int) values[off++]) - 1) << 4; | ||
| flag |= (encodeValue((int) values[off++]) - 1) << 2; | ||
| flag |= (encodeValue((int) values[off++]) - 1); | ||
| bytes[0] = flag; | ||
| out.writeBytes(bytes, byteOffset); | ||
| } | ||
|
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| // tail vints | ||
| for (; off < limit; off++) { | ||
| out.writeVInt((int) values[off]); | ||
| } | ||
| } | ||
| } |
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55 changes: 55 additions & 0 deletions
55
lucene/core/src/test/org/apache/lucene/codecs/lucene99/TestGroupVInt.java
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| Original file line number | Diff line number | Diff line change |
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| @@ -0,0 +1,55 @@ | ||
| /* | ||
| * 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.codecs.lucene99; | ||
|
|
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| import com.carrotsearch.randomizedtesting.generators.RandomNumbers; | ||
| import java.io.IOException; | ||
| import org.apache.lucene.store.ByteArrayDataInput; | ||
| import org.apache.lucene.store.ByteArrayDataOutput; | ||
| import org.apache.lucene.tests.util.LuceneTestCase; | ||
| import org.apache.lucene.tests.util.TestUtil; | ||
| import org.apache.lucene.util.ArrayUtil; | ||
| import org.apache.lucene.util.packed.PackedInts; | ||
|
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| public class TestGroupVInt extends LuceneTestCase { | ||
|
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| public void testEncodeDecode() throws IOException { | ||
| long[] values = new long[ForUtil.BLOCK_SIZE]; | ||
| long[] restored = new long[ForUtil.BLOCK_SIZE]; | ||
| final int iterations = atLeast(100); | ||
|
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| final GroupVIntWriter w = new GroupVIntWriter(); | ||
| byte[] encoded = new byte[(int) (Integer.BYTES * ForUtil.BLOCK_SIZE * 1.25)]; | ||
|
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| for (int i = 0; i < iterations; i++) { | ||
| final int bpv = TestUtil.nextInt(random(), 1, 31); | ||
| final int numValues = TestUtil.nextInt(random(), 1, ForUtil.BLOCK_SIZE); | ||
|
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| // encode | ||
| for (int j = 0; j < numValues; j++) { | ||
| values[j] = RandomNumbers.randomIntBetween(random(), 0, (int) PackedInts.maxValue(bpv)); | ||
| } | ||
| w.writeValues(new ByteArrayDataOutput(encoded), values, numValues); | ||
|
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| // decode | ||
| GroupVIntReader.readValues(new ByteArrayDataInput(encoded), restored, numValues); | ||
| assertArrayEquals( | ||
| ArrayUtil.copyOfSubArray(values, 0, numValues), | ||
| ArrayUtil.copyOfSubArray(restored, 0, numValues)); | ||
| } | ||
| } | ||
| } |