mayya-sharipova commented on code in PR #14331: URL: https://github.com/apache/lucene/pull/14331#discussion_r2005464935
########## lucene/core/src/java/org/apache/lucene/util/hnsw/MergingHnswGraphBuilder.java: ########## @@ -0,0 +1,198 @@ +/* + * 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.hnsw; + +import static org.apache.lucene.search.DocIdSetIterator.NO_MORE_DOCS; + +import java.io.IOException; +import java.util.HashSet; +import java.util.Set; +import org.apache.lucene.util.BitSet; + +/** + * A graph builder that is used during segments' merging. + * + * <p>This builder uses a smart algorithm to merge multiple graphs into a single graph. The + * algorithm is based on the idea if we know where we want to insert a node, we have a good idea of + * where we want to insert its neighbours. + * + * <p>The algorithm is based on the following steps: 1. Get all graphs that don't have deletions and + * sort them by size. 2. Copy the largest graph to the new graph (gL). 3. For each remaining small + * graph (gS) - Find the nodes that best cover gS: join set `j`. These nodes will be inserted into + * gL as usual: by searching gL to find the best candidates: `w` to which connect the nodes. - For + * each remaining node in gS: - we do NOT do search in gL. Instead, we form `w` by union of the + * node's neighbors' in Gs and the node's neighbors' neighbors' in gL. + * + * <p>We expect the size of join set `j` to be small, 1/5-1/2 of size gS. And for the rest of the + * nodes of gS, we expect savings by not doing extra search in gL. + * + * @lucene.experimental + */ Review Comment: Addressed in cb852a6387a09ba43049b8a24f1e026c309b368b -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: issues-unsubscr...@lucene.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: issues-unsubscr...@lucene.apache.org For additional commands, e-mail: issues-h...@lucene.apache.org
