lamgary commented on code in PR #26134: URL: https://github.com/apache/flink/pull/26134#discussion_r1949665932
########## flink-state-backends/flink-statebackend-rocksdb/src/main/java/org/apache/flink/state/rocksdb/iterator/RocksMultiStateKeysIterator.java: ########## @@ -0,0 +1,180 @@ +/* + * 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.flink.state.rocksdb.iterator; + +import org.apache.flink.api.common.typeutils.TypeSerializer; +import org.apache.flink.core.memory.DataInputDeserializer; +import org.apache.flink.runtime.state.CompositeKeySerializationUtils; +import org.apache.flink.state.rocksdb.RocksIteratorWrapper; +import org.apache.flink.util.FlinkRuntimeException; + +import javax.annotation.Nonnull; +import javax.annotation.Nullable; + +import java.io.IOException; +import java.util.Arrays; +import java.util.Iterator; +import java.util.List; +import java.util.NoSuchElementException; +import java.util.Objects; + +import static org.apache.flink.state.rocksdb.iterator.AbstractRocksStateKeysIterator.isMatchingNameSpace; + +/** + * Adapter class to bridge between {@link RocksIteratorWrapper} and {@link Iterator} to iterate over + * the keys. This class is not thread safe. + * + * @param <K> the type of the iterated objects, which are keys in RocksDB. + */ +public class RocksMultiStateKeysIterator<K> implements AutoCloseable, Iterator<K> { + + private final List<RocksIteratorWrapper> iterators; + private final List<String> states; + private final TypeSerializer<K> keySerializer; + private final List<Boolean> ambiguousKeyPossibles; + private final int keyGroupPrefixBytes; + private final byte[] namespaceBytes; + private final DataInputDeserializer byteArrayDataInputView; + + private final byte[][] iteratorKeys; + private K previousKey; + private K nextKey; + + public RocksMultiStateKeysIterator( + List<RocksIteratorWrapper> iterators, + List<String> states, + @Nonnull TypeSerializer<K> keySerializer, + int keyGroupPrefixBytes, + List<Boolean> ambiguousKeyPossibles, + @Nonnull byte[] namespaceBytes) { + this.iterators = iterators; + this.states = states; + this.keySerializer = keySerializer; + this.ambiguousKeyPossibles = ambiguousKeyPossibles; + this.keyGroupPrefixBytes = keyGroupPrefixBytes; + this.namespaceBytes = namespaceBytes; + this.byteArrayDataInputView = new DataInputDeserializer(); + this.iteratorKeys = new byte[iterators.size()][]; + Arrays.fill(iteratorKeys, null); + this.previousKey = null; + this.nextKey = null; + } + + @Override + public boolean hasNext() { + try { + while (nextKey == null && hasDataToProcess()) { + pullKeysFromIterators(); + K smallestIteratorKey = calculateSmallestKeyFromLocalData(); + if (smallestIteratorKey != null) { + previousKey = smallestIteratorKey; + nextKey = smallestIteratorKey; + } + } + } catch (Exception e) { + throw new FlinkRuntimeException( + "Failed to access states [" + String.join(",", states) + "]", e); + } + return nextKey != null; + } + + private boolean hasDataToProcess() { + boolean result = iterators.stream().anyMatch(RocksIteratorWrapper::isValid); + if (!result) { + for (int i = 0; i < iterators.size(); ++i) { + if (iteratorKeys[i] != null) { + result = true; + break; + } + } + } + return result; + } + + private void pullKeysFromIterators() { + for (int i = 0; i < iterators.size(); ++i) { + var iterator = iterators.get(i); + if (iteratorKeys[i] == null && iterator.isValid()) { + iteratorKeys[i] = iterator.key(); + iterator.next(); + } + } + } + + @Nullable + private K calculateSmallestKeyFromLocalData() throws IOException { Review Comment: Naive question, as I understand this works since we are assuming each iterator (which is created by `RocksDBOperationUtils.getRocksIterator`) returns keys in ascending order, do you know where/how this is guaranteed? ########## flink-state-backends/flink-statebackend-rocksdb/src/main/java/org/apache/flink/state/rocksdb/iterator/RocksMultiStateKeysIterator.java: ########## @@ -0,0 +1,180 @@ +/* + * 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.flink.state.rocksdb.iterator; + +import org.apache.flink.api.common.typeutils.TypeSerializer; +import org.apache.flink.core.memory.DataInputDeserializer; +import org.apache.flink.runtime.state.CompositeKeySerializationUtils; +import org.apache.flink.state.rocksdb.RocksIteratorWrapper; +import org.apache.flink.util.FlinkRuntimeException; + +import javax.annotation.Nonnull; +import javax.annotation.Nullable; + +import java.io.IOException; +import java.util.Arrays; +import java.util.Iterator; +import java.util.List; +import java.util.NoSuchElementException; +import java.util.Objects; + +import static org.apache.flink.state.rocksdb.iterator.AbstractRocksStateKeysIterator.isMatchingNameSpace; + +/** + * Adapter class to bridge between {@link RocksIteratorWrapper} and {@link Iterator} to iterate over + * the keys. This class is not thread safe. + * + * @param <K> the type of the iterated objects, which are keys in RocksDB. + */ +public class RocksMultiStateKeysIterator<K> implements AutoCloseable, Iterator<K> { + + private final List<RocksIteratorWrapper> iterators; + private final List<String> states; + private final TypeSerializer<K> keySerializer; + private final List<Boolean> ambiguousKeyPossibles; + private final int keyGroupPrefixBytes; + private final byte[] namespaceBytes; + private final DataInputDeserializer byteArrayDataInputView; + + private final byte[][] iteratorKeys; + private K previousKey; + private K nextKey; + + public RocksMultiStateKeysIterator( + List<RocksIteratorWrapper> iterators, + List<String> states, + @Nonnull TypeSerializer<K> keySerializer, + int keyGroupPrefixBytes, + List<Boolean> ambiguousKeyPossibles, + @Nonnull byte[] namespaceBytes) { + this.iterators = iterators; + this.states = states; + this.keySerializer = keySerializer; + this.ambiguousKeyPossibles = ambiguousKeyPossibles; + this.keyGroupPrefixBytes = keyGroupPrefixBytes; + this.namespaceBytes = namespaceBytes; + this.byteArrayDataInputView = new DataInputDeserializer(); + this.iteratorKeys = new byte[iterators.size()][]; + Arrays.fill(iteratorKeys, null); + this.previousKey = null; + this.nextKey = null; + } + + @Override + public boolean hasNext() { + try { + while (nextKey == null && hasDataToProcess()) { + pullKeysFromIterators(); + K smallestIteratorKey = calculateSmallestKeyFromLocalData(); + if (smallestIteratorKey != null) { + previousKey = smallestIteratorKey; + nextKey = smallestIteratorKey; + } + } + } catch (Exception e) { + throw new FlinkRuntimeException( + "Failed to access states [" + String.join(",", states) + "]", e); + } + return nextKey != null; + } + + private boolean hasDataToProcess() { + boolean result = iterators.stream().anyMatch(RocksIteratorWrapper::isValid); + if (!result) { + for (int i = 0; i < iterators.size(); ++i) { + if (iteratorKeys[i] != null) { + result = true; + break; + } + } + } + return result; + } + + private void pullKeysFromIterators() { + for (int i = 0; i < iterators.size(); ++i) { + var iterator = iterators.get(i); + if (iteratorKeys[i] == null && iterator.isValid()) { + iteratorKeys[i] = iterator.key(); + iterator.next(); + } + } + } + + @Nullable + private K calculateSmallestKeyFromLocalData() throws IOException { + int smallestIteratorKeyIndex = -1; + byte[] smallestIteratorKey = null; + for (int i = 0; i < iteratorKeys.length; ++i) { + var iteratorKey = iteratorKeys[i]; + if (iteratorKey != null + && (smallestIteratorKey == null + || Arrays.compare(iteratorKey, smallestIteratorKey) < 0)) { + smallestIteratorKeyIndex = i; + smallestIteratorKey = iteratorKey; + } + } + + if (smallestIteratorKey != null) { + for (int i = 0; i < iteratorKeys.length; ++i) { + if (Arrays.equals(iteratorKeys[i], smallestIteratorKey)) { + iteratorKeys[i] = null; + } + } + + byteArrayDataInputView.setBuffer( + smallestIteratorKey, + keyGroupPrefixBytes, + smallestIteratorKey.length - keyGroupPrefixBytes); + final K smallestIteratorKeyValue = + CompositeKeySerializationUtils.readKey( + keySerializer, + byteArrayDataInputView, + ambiguousKeyPossibles.get(smallestIteratorKeyIndex)); + if (isMatchingNameSpace( + smallestIteratorKey, + byteArrayDataInputView.getPosition(), + namespaceBytes) + && !Objects.equals(previousKey, smallestIteratorKeyValue)) { + return smallestIteratorKeyValue; Review Comment: nit: I originally thought in`smallestIteratorKeyValue` we were reading the `value` stored in RocksDb, but this refers to the deserialized version of of the `smallestIteratorKey`. We could rename: `byte[] smallestIteratorKey` -> `smallestIteratorKeyBytes` `smallestIteratorKeyValue` -> `smallestIteratorKey` -- 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: issues-unsubscr...@flink.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org
