nicktelford commented on code in PR #22625: URL: https://github.com/apache/kafka/pull/22625#discussion_r3451267263
########## streams/src/main/java/org/apache/kafka/streams/state/internals/RocksDBTransactionBuffer.java: ########## @@ -0,0 +1,323 @@ +/* + * 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.kafka.streams.state.internals; + +import org.apache.kafka.common.utils.Bytes; +import org.apache.kafka.streams.KeyValue; +import org.apache.kafka.streams.errors.ProcessorStateException; + +import org.rocksdb.ColumnFamilyHandle; +import org.rocksdb.RocksDB; +import org.rocksdb.RocksDBException; +import org.rocksdb.RocksIterator; +import org.rocksdb.WriteBatch; +import org.rocksdb.WriteOptions; + +import java.util.ArrayList; +import java.util.Collections; +import java.util.List; +import java.util.Map; +import java.util.NavigableMap; +import java.util.NoSuchElementException; +import java.util.Optional; +import java.util.TreeMap; + +/** + * A {@link TransactionBuffer} implementation for RocksDB-backed stores. + * Uses a {@link WriteBatch} (without index) to accumulate writes for atomic commit. + * Reads are handled entirely by the shared {@code ConcurrentSkipListMap} in + * {@link AbstractTransactionBuffer}, so a {@code WriteBatchWithIndex} is not needed. + * <p> + * Range deletions ({@link #stageDeleteRange}) are only supported by RocksDB-backed stores + * and are owned entirely by this class; {@link AbstractTransactionBuffer} carries no + * tombstone state. + */ +class RocksDBTransactionBuffer extends AbstractTransactionBuffer<Bytes> { + + private final RocksDB db; + private final ColumnFamilyHandle cfHandle; + private final WriteOptions wOptions; + private final String storeName; + private WriteBatch writeBatch; + private volatile NavigableMap<Bytes, List<Bytes>> rangeTombstones = Collections.emptyNavigableMap(); + + RocksDBTransactionBuffer(final RocksDB db, + final ColumnFamilyHandle cfHandle, + final WriteOptions wOptions, + final String storeName) { + this.db = db; + this.cfHandle = cfHandle; + this.wOptions = wOptions; + this.storeName = storeName; + this.writeBatch = new WriteBatch(); + } + + @Override + int estimateKeySize(final Bytes key) { + return key.get().length; + } + + @Override + void stageToBackend(final Bytes key, final byte[] value) { + stage(cfHandle, key, value); + } + + /** + * Stages a write for an explicit column family. Updates the shared read buffer + * ({@code pendingWrites}) and appends the write to the shared {@link WriteBatch} + * under {@code cf}, so every staged CF is committed atomically on {@link #commit()}. + */ + void stage(final ColumnFamilyHandle cf, final Bytes key, final byte[] value) { + pendingWrites.put(key, Optional.ofNullable(value)); + pendingWritesBytes += estimateKeySize(key) + (value != null ? value.length : 0); + try { + if (value != null) { + writeBatch.put(cf, key.get(), value); + } else { + writeBatch.delete(cf, key.get()); + } + } catch (final RocksDBException e) { + throw new ProcessorStateException("Error staging write in transaction buffer for store " + storeName, e); + } + } + + /** + * Stages a range deletion for an explicit column family. Updates the shared + * {@code pendingWrites} and {@code rangeTombstones} so iterators opened before + * commit hide the deleted range, and appends the range delete to the shared + * {@link WriteBatch} under {@code cf}. + */ + void stageDeleteRange(final ColumnFamilyHandle cf, final Bytes from, final Bytes to) { + pendingWrites.subMap(from, true, to, false).clear(); + final TreeMap<Bytes, List<Bytes>> copy = new TreeMap<>(rangeTombstones); + copy.computeIfAbsent(from, k -> new ArrayList<>()).add(to); + rangeTombstones = copy; + pendingWritesBytes += estimateKeySize(from) + estimateKeySize(to); + try { + writeBatch.deleteRange(cf, from.get(), to.get()); + } catch (final RocksDBException e) { + throw new ProcessorStateException("Error staging delete range in transaction buffer for store " + storeName, e); + } + } + + @Override + public Optional<byte[]> get(final Bytes key) { + final Optional<byte[]> staged = pendingWrites.get(key); + if (staged != null) { + return staged; + } + if (isCoveredByRangeTombstone(key, rangeTombstones)) { + return Optional.empty(); + } + return null; + } + + @Override + public boolean isEmpty() { + return super.isEmpty() && rangeTombstones.isEmpty(); + } + + ManagedKeyValueIterator<Bytes, byte[]> all(final ColumnFamilyHandle cf, final boolean forward) { + if (Thread.currentThread() == ownerThread) { + final ManagedKeyValueIterator<Bytes, byte[]> baseIter = newBaseIterator(cf, null, null, forward, true); + return new StagedMergeIterator<>(pendingWrites, baseIter, forward); + } + return snapshotScan(cf, null, null, forward, true); + } + + ManagedKeyValueIterator<Bytes, byte[]> range(final ColumnFamilyHandle cf, + final Bytes from, final Bytes to, + final boolean forward, final boolean toInclusive) { + if (Thread.currentThread() == ownerThread) { + final ManagedKeyValueIterator<Bytes, byte[]> baseIter = newBaseIterator(cf, from, to, forward, toInclusive); + final NavigableMap<Bytes, Optional<byte[]>> stagingView = boundStaging(from, to, toInclusive); + return new StagedMergeIterator<>(stagingView, baseIter, forward); Review Comment: Ahh yes, same as in the AbstractTransactionBuffer :smile: Fixed. -- This is an automated message from the Apache Git Service. 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