maedhroz commented on code in PR #2409: URL: https://github.com/apache/cassandra/pull/2409#discussion_r1228355204
########## src/java/org/apache/cassandra/index/sai/disk/v1/bbtree/NumericIndexWriter.java: ########## @@ -0,0 +1,179 @@ +/* + * 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.bbtree; + +import java.io.IOException; +import java.util.ArrayList; +import java.util.LinkedHashMap; +import java.util.List; +import java.util.Map; + +import com.google.common.annotations.VisibleForTesting; +import com.google.common.base.MoreObjects; + +import org.apache.cassandra.index.sai.IndexContext; +import org.apache.cassandra.index.sai.disk.format.IndexComponent; +import org.apache.cassandra.index.sai.disk.format.IndexDescriptor; +import org.apache.cassandra.index.sai.disk.v1.segment.SegmentMetadata; +import org.apache.lucene.store.IndexOutput; +import org.apache.lucene.util.packed.PackedInts; +import org.apache.lucene.util.packed.PackedLongValues; + +import static com.google.common.base.Preconditions.checkArgument; + + +/** + * Specialized writer for 1-dim point values, that builds them into a BKD tree with auxiliary posting lists on eligible + * tree levels. + * + * Given sorted input {@link org.apache.lucene.codecs.MutablePointValues}, 1-dim case allows to optimise flush process, because we don't need to + * buffer all point values to sort them. + */ +public class NumericIndexWriter +{ + public static final int MAX_POINTS_IN_LEAF_NODE = BlockBalancedTreeWriter.DEFAULT_MAX_POINTS_IN_LEAF_NODE; + + private final BlockBalancedTreeWriter writer; + private final IndexDescriptor indexDescriptor; + private final IndexContext indexContext; + private final int bytesPerValue; + + /** + * @param maxSegmentRowId maximum possible segment row ID, used to create `maxDoc` for kd-tree + */ + public NumericIndexWriter(IndexDescriptor indexDescriptor, + IndexContext indexContext, + int bytesPerValue, + long maxSegmentRowId) + { + this(indexDescriptor, indexContext, MAX_POINTS_IN_LEAF_NODE, bytesPerValue, maxSegmentRowId); + } + + @VisibleForTesting + public NumericIndexWriter(IndexDescriptor indexDescriptor, + IndexContext indexContext, + int maxPointsInLeafNode, + int bytesPerValue, + long maxSegmentRowId) + { + checkArgument(maxSegmentRowId >= 0, "[%s] maxRowId must be non-negative value, but got %s", indexContext.getIndexName(), maxSegmentRowId); + + this.indexDescriptor = indexDescriptor; + this.indexContext = indexContext; + this.bytesPerValue = bytesPerValue; + this.writer = new BlockBalancedTreeWriter(maxSegmentRowId + 1, bytesPerValue, maxPointsInLeafNode); + } + + @Override + public String toString() + { + return MoreObjects.toStringHelper(this) + .add("bytesPerDim", bytesPerValue) + .add("bufferedPoints", writer.getPointCount()) + .toString(); + } + + public static class LeafCallback implements BlockBalancedTreeWriter.OneDimensionBKDWriterCallback + { + final List<PackedLongValues> postings = new ArrayList<>(); + + public int numLeaves() + { + return postings.size(); + } + + @Override + public void writeLeafDocs(BlockBalancedTreeWriter.RowIDAndIndex[] sortedByRowID, int offset, int count) + { + PackedLongValues.Builder builder = PackedLongValues.monotonicBuilder(PackedInts.COMPACT); + + for (int i = offset; i < count; ++i) + { + builder.add(sortedByRowID[i].rowID); + } + postings.add(builder.build()); + } + } + + /** + * Writes a k-d tree and posting lists from a {@link org.apache.lucene.codecs.MutablePointValues}. + * + * @param values points to write + * + * @return metadata describing the location and size of this kd-tree in the overall SSTable kd-tree component file + */ + public SegmentMetadata.ComponentMetadataMap writeAll(IntersectingPointValues values) throws IOException Review Comment: For variable names and such, I'm fine with "tree" as a prefix, tbh It's not like it's unclear which tree we mean in this context. -- This is an automated message from the Apache Git Service. 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