cshuo commented on code in PR #18083: URL: https://github.com/apache/hudi/pull/18083#discussion_r2972586832
########## hudi-flink-datasource/hudi-flink/src/main/java/org/apache/hudi/sink/append/AppendWriteFunctionWithContinuousSort.java: ########## @@ -0,0 +1,330 @@ +/* + * 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.hudi.sink.append; + +import org.apache.hudi.configuration.FlinkOptions; +import org.apache.hudi.exception.HoodieException; +import org.apache.hudi.exception.HoodieIOException; +import org.apache.hudi.sink.StreamWriteOperatorCoordinator; +import org.apache.hudi.sink.bulk.sort.SortOperatorGen; + +import org.apache.flink.configuration.Configuration; +import org.apache.flink.core.memory.MemorySegment; +import org.apache.flink.core.memory.MemorySegmentFactory; +import org.apache.flink.table.data.RowData; +import org.apache.flink.table.planner.codegen.sort.SortCodeGenerator; +import org.apache.flink.table.runtime.typeutils.RowDataSerializer; +import org.apache.flink.table.runtime.generated.GeneratedNormalizedKeyComputer; +import org.apache.flink.table.runtime.generated.GeneratedRecordComparator; +import org.apache.flink.table.runtime.generated.NormalizedKeyComputer; +import org.apache.flink.table.runtime.generated.RecordComparator; +import org.apache.flink.table.types.logical.RowType; +import org.apache.flink.util.Collector; + +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +import java.io.IOException; +import java.util.Arrays; +import java.util.Iterator; +import java.util.List; +import java.util.Map; +import java.util.TreeMap; +import java.util.stream.Collectors; + +/** + * Sink function to write data with continuous sorting for improved compression. + * + * <p>Unlike {@link AppendWriteFunctionWithBIMBufferSort} which uses batch sorting, + * this function maintains sorted order continuously using a TreeMap, providing: + * <ul> + * <li>Non-blocking inserts (O(log n) vs O(1) + periodic O(n log n))</li> + * <li>Incremental draining without re-sorting</li> + * <li>Predictable latency (no sort spikes)</li> + * </ul> + * + * <p>Strategy: + * <ol> + * <li>Records are inserted in sorted order (TreeMap)</li> + * <li>When buffer reaches max capacity, oldest record(s) are drained synchronously</li> + * <li>Drain size is configurable to balance latency vs. throughput vs compression ratio</li> + * </ol> + * + * @param <T> Type of the input record + * @see StreamWriteOperatorCoordinator + */ +public class AppendWriteFunctionWithContinuousSort<T> extends AppendWriteFunction<T> { + + private static final Logger LOG = LoggerFactory.getLogger(AppendWriteFunctionWithContinuousSort.class); + + private final long maxCapacity; + private final int drainSize; + + private transient TreeMap<SortKey, RowData> sortedRecords; + private transient long insertionSequence; + + // Sort key computation + private transient NormalizedKeyComputer normalizedKeyComputer; + private transient RecordComparator recordComparator; + private transient MemorySegment reusableKeySegment; + private transient int normalizedKeySize; + private transient boolean objectReuseEnabled; + private transient RowDataSerializer rowDataSerializer; + + // Metrics + private transient long totalDrainOperations; + private transient long totalDrainedRecords; + private transient long totalInserted; + + public AppendWriteFunctionWithContinuousSort(Configuration config, RowType rowType) { + super(config, rowType); + + // Configuration + this.maxCapacity = config.get(FlinkOptions.WRITE_BUFFER_SIZE); + this.drainSize = config.get(FlinkOptions.WRITE_BUFFER_SORT_CONTINUOUS_DRAIN_SIZE); + + LOG.info("AppendWriteFunctionWithContinuousSort created: maxCapacity={}, drainSize={}", + maxCapacity, drainSize); + } + + @Override + public void open(Configuration parameters) throws Exception { + // Validate configuration before calling super.open() which requires Flink runtime context + if (maxCapacity <= 0) { + throw new IllegalArgumentException( + String.format("Buffer capacity must be positive, got: %d", maxCapacity)); + } + + if (drainSize <= 0) { + throw new IllegalArgumentException( + String.format("Drain size must be positive, got: %d", drainSize)); + } + + // Resolve sort keys, falling back to record key if not specified + List<String> sortKeyList = AppendWriteFunctions.resolveSortKeys(config); + + super.open(parameters); + + LOG.info("Initializing continuous sort with keys: {}", sortKeyList); + + // Create sort code generator for normalized key computation and record comparison + SortOperatorGen sortOperatorGen = new SortOperatorGen(rowType, sortKeyList.toArray(new String[0])); + SortCodeGenerator codeGenerator = sortOperatorGen.createSortCodeGenerator(); + GeneratedNormalizedKeyComputer generatedKeyComputer = codeGenerator.generateNormalizedKeyComputer("ContinuousSortKeyComputer"); + GeneratedRecordComparator generatedComparator = codeGenerator.generateRecordComparator("ContinuousSortComparator"); + + // Instantiate code-generated components + ClassLoader classLoader = Thread.currentThread().getContextClassLoader(); + this.normalizedKeyComputer = generatedKeyComputer.newInstance(classLoader); + this.recordComparator = generatedComparator.newInstance(classLoader); + this.normalizedKeySize = normalizedKeyComputer.getNumKeyBytes(); + + // Initialize TreeMap with comparator that uses normalized keys for fast comparison + // and falls back to RecordComparator for full comparison when normalized keys are equal + this.sortedRecords = new TreeMap<>((k1, k2) -> { + MemorySegment seg1 = MemorySegmentFactory.wrap(k1.keyBytes); + MemorySegment seg2 = MemorySegmentFactory.wrap(k2.keyBytes); + + int cmp = normalizedKeyComputer.compareKey(seg1, 0, seg2, 0); + if (cmp != 0) { + return cmp; + } + // Normalized keys are equal - use full record comparison for correct ordering + cmp = recordComparator.compare(k1.record, k2.record); + if (cmp != 0) { + return cmp; + } + // Records are equal by sort keys - use insertion order for stability + return Long.compare(k1.insertionOrder, k2.insertionOrder); + }); + this.insertionSequence = 0L; + + // Allocate reusable on-heap buffer for computing keys + byte[] reusableKeyBuffer = new byte[normalizedKeySize]; + this.reusableKeySegment = MemorySegmentFactory.wrap(reusableKeyBuffer); + + // Detect object reuse mode and create serializer for copying if needed + this.objectReuseEnabled = getRuntimeContext().isObjectReuseEnabled(); + if (this.objectReuseEnabled) { + this.rowDataSerializer = new RowDataSerializer(rowType); + } + + // Initialize metrics + this.totalDrainOperations = 0; + this.totalDrainedRecords = 0; + this.totalInserted = 0; + + LOG.info("AppendWriteFunctionWithContinuousSort initialized successfully"); + } + + @Override + public void processElement(T value, Context ctx, Collector<RowData> out) throws Exception { + RowData data = (RowData) value; + + // Check if buffer has reached max capacity + if (sortedRecords.size() >= maxCapacity) { + drainRecords(drainSize); + + // Verify there's space after draining + if (sortedRecords.size() >= maxCapacity) { + throw new HoodieException( + String.format("Buffer cannot accept record after draining. " + + "Buffer size: %d, maxCapacity: %d, drainSize: %d", + sortedRecords.size(), maxCapacity, drainSize)); + } + } + + // Copy RowData when object reuse is enabled to prevent mutation after insertion + if (objectReuseEnabled) { + data = rowDataSerializer.copy(data); + } + + // Write to buffer (maintains sorted order) + // Compute normalized key into reusable segment + normalizedKeyComputer.putKey(data, reusableKeySegment, 0); + + // Create sort key (copies the normalized key from reusable segment) + SortKey key = new SortKey(reusableKeySegment, normalizedKeySize, data, insertionSequence++); + + // Store the RowData + sortedRecords.put(key, data); + + totalInserted++; + } + + /** + * Drain oldest records from buffer and write to storage. + */ + private void drainRecords(int count) throws IOException { + if (sortedRecords.isEmpty()) { + return; + } + + // Initialize writer if needed + if (this.writerHelper == null) { + initWriterHelper(); + } + + // Drain records from TreeMap + int actualCount = Math.min(count, sortedRecords.size()); + int drained = 0; + + Iterator<Map.Entry<SortKey, RowData>> iterator = sortedRecords.entrySet().iterator(); + while (iterator.hasNext() && drained < actualCount) { + Map.Entry<SortKey, RowData> entry = iterator.next(); + RowData record = entry.getValue(); + + // Write record + writerHelper.write(record); + + // Remove from TreeMap - memory immediately reclaimed + iterator.remove(); + drained++; + } + + totalDrainOperations++; + totalDrainedRecords += drained; + } + + @Override + public void snapshotState() { + try { + // Drain all remaining records and reset for next checkpoint interval + if (!sortedRecords.isEmpty()) { + LOG.info("Snapshot: draining {} remaining records", sortedRecords.size()); + drainRecords(sortedRecords.size()); + sortedRecords.clear(); + insertionSequence = 0L; + } + + LOG.info("Snapshot complete: total drained={}, operations={}", + totalDrainedRecords, totalDrainOperations); + + } catch (IOException e) { + throw new HoodieIOException("Failed to drain buffer during snapshot", e); + } finally { + super.snapshotState(); + } + } + + @Override + public void endInput() { + try { + // Drain all remaining records and clear buffer + if (!sortedRecords.isEmpty()) { + LOG.info("EndInput: draining {} remaining records", sortedRecords.size()); + drainRecords(sortedRecords.size()); + sortedRecords.clear(); + insertionSequence = 0L; + } + + } catch (IOException e) { + throw new HoodieIOException("Failed to drain buffer during endInput", e); + } finally { Review Comment: Let's move `super.endInput();` out of the `finally` clause like other append write functions. -- This is an automated message from the Apache Git Service. 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