maedhroz commented on code in PR #2409: URL: https://github.com/apache/cassandra/pull/2409#discussion_r1228451742
########## src/java/org/apache/cassandra/index/sai/disk/v1/bbtree/BlockBalancedTreeRamBuffer.java: ########## @@ -0,0 +1,172 @@ +/* + * 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.stream.IntStream; + +import com.google.common.base.Preconditions; + +import org.apache.lucene.util.Accountable; +import org.apache.lucene.util.ByteBlockPool; +import org.apache.lucene.util.BytesRef; +import org.apache.lucene.util.Counter; +import org.apache.lucene.util.packed.PackedInts; +import org.apache.lucene.util.packed.PackedLongValues; + +/** + * On-heap buffer for point values that provides a sortable view of itself as {@link IntersectingPointValues}. + */ +public class BlockBalancedTreeRamBuffer implements Accountable +{ + private final Counter bytesUsed; + private final ByteBlockPool bytes; + private final byte[] packedValue; + private final PackedLongValues.Builder rowIDsBuilder; + private int numPoints; + private int numRows; + private int lastSegmentRowID = -1; + private boolean closed = false; + + public BlockBalancedTreeRamBuffer(int pointNumBytes) + { + this.bytesUsed = Counter.newCounter(); + + this.bytes = new ByteBlockPool(new ByteBlockPool.DirectTrackingAllocator(bytesUsed)); + + packedValue = new byte[pointNumBytes]; + + rowIDsBuilder = PackedLongValues.deltaPackedBuilder(PackedInts.COMPACT); + bytesUsed.addAndGet(rowIDsBuilder.ramBytesUsed()); + } + + @Override + public long ramBytesUsed() + { + return bytesUsed.get(); + } + + public int numRows() + { + return numRows; + } + + public long addPackedValue(int segmentRowId, BytesRef value) + { + ensureOpen(); + + assert value.length == packedValue.length : "The value has length=" + value.length + " but should be " + packedValue.length; + + long startingBytesUsed = bytesUsed.get(); + long startingRowIDsBytesUsed = rowIDsBuilder.ramBytesUsed(); + + rowIDsBuilder.add(segmentRowId); + bytes.append(value); + + if (segmentRowId != lastSegmentRowID) + { + numRows++; + lastSegmentRowID = segmentRowId; + } + + numPoints++; + + long rowIDsAllocatedBytes = rowIDsBuilder.ramBytesUsed() - startingRowIDsBytesUsed; + long endingBytesAllocated = bytesUsed.addAndGet(rowIDsAllocatedBytes); + + return endingBytesAllocated - startingBytesUsed; + } + + public IntersectingPointValues asPointValues() + { + ensureOpen(); + // building packed longs is destructive + closed = true; + final PackedLongValues rowIDs = rowIDsBuilder.build(); + return new IntersectingPointValues() + { + final int[] ords = IntStream.range(0, numPoints).toArray(); + + @Override + public void getValue(int i, BytesRef bytesRef) + { + final long offset = (long) packedValue.length * (long) ords[i]; + bytesRef.length = packedValue.length; + bytes.setRawBytesRef(bytesRef, offset); + } + + @Override + public byte getByteAt(int i, int k) + { + final long offset = (long) packedValue.length * (long) ords[i] + (long) k; + + return bytes.readByte(offset); + } + + @Override + public int getDocID(int i) + { + return Math.toIntExact(rowIDs.get(ords[i])); + } + + @Override + public void swap(int i, int j) + { + int tmp = ords[i]; + ords[i] = ords[j]; + ords[j] = tmp; + } + + @Override + public void intersect(IntersectVisitor visitor) throws IOException + { + final BytesRef scratch = new BytesRef(); + for (int i = 0; i < numPoints; i++) + { + getValue(i, scratch); + assert scratch.length == packedValue.length; + System.arraycopy(scratch.bytes, scratch.offset, packedValue, 0, packedValue.length); + visitor.visit(getDocID(i), packedValue); + } + } + + @Override + public int getBytesPerDimension() + { + return packedValue.length; + } + + @Override + public long size() + { + return numPoints; + } + + @Override + public int getDocCount() + { + return numRows; + } + }; + } + + private void ensureOpen() + { + Preconditions.checkState(!closed, "Expected open buffer."); Review Comment: super nit: This could probably be an assertion as well, given it would indicate programmer error, but not super important... -- This is an automated message from the Apache Git Service. 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