jbellis commented on code in PR #2673: URL: https://github.com/apache/cassandra/pull/2673#discussion_r1357115095
########## src/java/org/apache/cassandra/index/sai/disk/v1/segment/VectorIndexSegmentSearcher.java: ########## @@ -0,0 +1,288 @@ +/* + * 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.cassandra.index.sai.disk.v1.segment; + +import java.io.IOException; +import java.lang.invoke.MethodHandles; +import java.nio.ByteBuffer; +import java.util.Arrays; +import javax.annotation.Nullable; + +import com.google.common.base.MoreObjects; +import com.google.common.base.Preconditions; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +import io.github.jbellis.jvector.util.Bits; +import io.github.jbellis.jvector.util.SparseFixedBitSet; +import org.agrona.collections.IntArrayList; +import org.apache.cassandra.db.PartitionPosition; +import org.apache.cassandra.db.marshal.VectorType; +import org.apache.cassandra.dht.AbstractBounds; +import org.apache.cassandra.index.sai.IndexContext; +import org.apache.cassandra.index.sai.QueryContext; +import org.apache.cassandra.index.sai.VectorQueryContext; +import org.apache.cassandra.index.sai.disk.PrimaryKeyMap; +import org.apache.cassandra.index.sai.disk.v1.PerColumnIndexFiles; +import org.apache.cassandra.index.sai.disk.v1.postings.ReorderingPostingList; +import org.apache.cassandra.index.sai.disk.v1.vector.DiskAnn; +import org.apache.cassandra.index.sai.iterators.KeyRangeIterator; +import org.apache.cassandra.index.sai.plan.Expression; +import org.apache.cassandra.index.sai.postings.IntArrayPostingList; +import org.apache.cassandra.index.sai.postings.PeekablePostingList; +import org.apache.cassandra.index.sai.postings.PostingList; +import org.apache.cassandra.index.sai.utils.RangeUtil; +import org.apache.cassandra.index.sai.utils.TypeUtil; + +/** + * Executes ANN search against a vector graph for an individual index segment. + */ +public class VectorIndexSegmentSearcher extends IndexSegmentSearcher +{ + private static final Logger logger = LoggerFactory.getLogger(MethodHandles.lookup().lookupClass()); + + private final DiskAnn graph; + private final VectorType<float[]> type; + private final int maxBruteForceRows; + private final ThreadLocal<SparseFixedBitSet> cachedBitSets; + + @SuppressWarnings("unchecked") + VectorIndexSegmentSearcher(PrimaryKeyMap.Factory primaryKeyMapFactory, + PerColumnIndexFiles perIndexFiles, + SegmentMetadata segmentMetadata, + IndexContext indexContext) throws IOException + { + super(primaryKeyMapFactory, perIndexFiles, segmentMetadata, indexContext); + graph = new DiskAnn(segmentMetadata.componentMetadatas, perIndexFiles, indexContext); + type = (VectorType<float[]>) indexContext.getValidator(); + cachedBitSets = ThreadLocal.withInitial(() -> new SparseFixedBitSet(graph.size())); + + // estimate the number of comparisons that a search would require; use brute force if we have + // fewer rows involved than that + maxBruteForceRows = (int)(indexContext.getIndexWriterConfig().getMaximumNodeConnections() * Math.log(graph.size())); Review Comment: this turns out to be a very bad estimate, and estimate quality is much more important than I thought at first, because if you only have M results from the other predicates and you are looking for top K in an index of N, where M << N, the dominant factor in your search is just looking for M valid results. unfortunately I don't have a single-commit fix for this, it evolved across several in the vsearch branch. okay to leave this for followup but it's quite important to have it in the released version. -- 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: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
