msokolov commented on code in PR #12254: URL: https://github.com/apache/lucene/pull/12254#discussion_r1187789321
########## lucene/core/src/java/org/apache/lucene/util/hnsw/ConcurrentHnswGraphBuilder.java: ########## @@ -0,0 +1,329 @@ +/* + * 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 java.lang.Math.log; + +import java.io.IOException; +import java.util.Objects; +import java.util.concurrent.ConcurrentSkipListSet; +import java.util.concurrent.ExecutorService; +import java.util.concurrent.Executors; +import java.util.concurrent.Semaphore; +import java.util.concurrent.ThreadLocalRandom; +import java.util.concurrent.ThreadPoolExecutor; +import java.util.concurrent.TimeUnit; +import org.apache.lucene.index.VectorEncoding; +import org.apache.lucene.index.VectorSimilarityFunction; +import org.apache.lucene.util.AtomicBitSet; +import org.apache.lucene.util.FixedBitSet; +import org.apache.lucene.util.InfoStream; +import org.apache.lucene.util.NamedThreadFactory; +import org.apache.lucene.util.hnsw.ConcurrentOnHeapHnswGraph.NodeAtLevel; + +/** + * Builder for Concurrent HNSW graph. See {@link HnswGraph} for a high level overview, and the + * comments to `addGraphNode` for details on the concurrent building approach. + * + * @param <T> the type of vector + */ +public final class ConcurrentHnswGraphBuilder<T> implements IHnswGraphBuilder<T> { + + /** Default number of maximum connections per node */ + public static final int DEFAULT_MAX_CONN = 16; + + /** + * Default number of the size of the queue maintained while searching during a graph construction. + */ + public static final int DEFAULT_BEAM_WIDTH = 100; + + /** A name for the HNSW component for the info-stream * */ + public static final String HNSW_COMPONENT = "HNSW"; + + private final int beamWidth; + private final double ml; + private final ThreadLocal<NeighborArray> scratchNeighbors; + + private final VectorSimilarityFunction similarityFunction; + private final VectorEncoding vectorEncoding; + private final RandomAccessVectorValues<T> vectors; + private final ThreadLocal<HnswGraphSearcher<T>> graphSearcher; + + final ConcurrentOnHeapHnswGraph hnsw; + private final ConcurrentSkipListSet<NodeAtLevel> insertionsInProgress = + new ConcurrentSkipListSet<>(); + + private InfoStream infoStream = InfoStream.getDefault(); + + // we need two sources of vectors in order to perform diversity check comparisons without + // colliding + private final RandomAccessVectorValues<T> vectorsCopy; + private final AtomicBitSet initializedNodes; Review Comment: calling this `initializedNodes` confused me since the usage here is really different from the variable of the same name in `HnswGraphBuilder` that is populated when initializing from another graph, but here we add to this set while adding nodes in `addNode`. I'm actually unclear why we need this and the check in `addGraphNode`. Aren't we guaranteed to insert each node exactly once? -- 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
