neoremind commented on a change in pull request #91: URL: https://github.com/apache/lucene/pull/91#discussion_r617406029
########## File path: lucene/core/src/java/org/apache/lucene/util/StableMSBRadixSorter.java ########## @@ -0,0 +1,91 @@ +/* + * 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.util; + +/** + * Stable radix sorter for variable-length strings. It has to check data beforehand to see if stable + * sort can be enabled or not. If not applicable, it works the same way as its parent class {@link + * MSBRadixSorter}. + * + * @lucene.internal + */ +public abstract class StableMSBRadixSorter extends MSBRadixSorter { + + protected boolean useStableSort; + + public StableMSBRadixSorter(int maxLength) { + super(maxLength); + } + + /** Check if stable sort can be enabled or not. */ + protected boolean isEnableStableSort(int from, int to) { + return false; + } + + /** + * If stable sort is applicable, do some closure logic, which might update some of the internal + * variable. + */ + protected void doClosureIfStableSortEnabled() {} + + /** Assign the from-th value to to-th position in another array which used temporarily. */ + protected void assign(int from, int to) { + throw new UnsupportedOperationException("not implement"); + } + + /** Finalize assign operation, to switch array. */ + protected void finalizeAssign(int from, int to) { + throw new UnsupportedOperationException("not implement"); + } + + @Override + public void sort(int from, int to) { + checkRange(from, to); + useStableSort = isEnableStableSort(from, to); + if (useStableSort) { + doClosureIfStableSortEnabled(); + } + sort(from, to, 0, 0); + } + + @Override + protected void reorder(int from, int to, int[] startOffsets, int[] endOffsets, int k) { + if (useStableSort) { + stableReorder(from, to, startOffsets, endOffsets, k); + } else { + super.reorder(from, to, startOffsets, endOffsets, k); + } Review comment: There is no silver bullet, the stable reorder runs faster, I think the reason is that it makes less swapping, but use extra space to store docid. ########## File path: lucene/core/src/java/org/apache/lucene/util/StableMSBRadixSorter.java ########## @@ -0,0 +1,91 @@ +/* + * 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.util; + +/** + * Stable radix sorter for variable-length strings. It has to check data beforehand to see if stable + * sort can be enabled or not. If not applicable, it works the same way as its parent class {@link + * MSBRadixSorter}. + * + * @lucene.internal + */ +public abstract class StableMSBRadixSorter extends MSBRadixSorter { + + protected boolean useStableSort; + + public StableMSBRadixSorter(int maxLength) { + super(maxLength); + } + + /** Check if stable sort can be enabled or not. */ + protected boolean isEnableStableSort(int from, int to) { + return false; + } + + /** + * If stable sort is applicable, do some closure logic, which might update some of the internal + * variable. + */ + protected void doClosureIfStableSortEnabled() {} + + /** Assign the from-th value to to-th position in another array which used temporarily. */ + protected void assign(int from, int to) { + throw new UnsupportedOperationException("not implement"); + } + + /** Finalize assign operation, to switch array. */ + protected void finalizeAssign(int from, int to) { + throw new UnsupportedOperationException("not implement"); + } + + @Override + public void sort(int from, int to) { + checkRange(from, to); + useStableSort = isEnableStableSort(from, to); + if (useStableSort) { + doClosureIfStableSortEnabled(); + } + sort(from, to, 0, 0); + } + + @Override + protected void reorder(int from, int to, int[] startOffsets, int[] endOffsets, int k) { + if (useStableSort) { + stableReorder(from, to, startOffsets, endOffsets, k); + } else { + super.reorder(from, to, startOffsets, endOffsets, k); + } Review comment: There is no silver bullet, the stable reorder runs faster, I think the reason is that it makes less swapping, but use extra temp space to store docid. -- This is an automated message from the Apache Git Service. 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