StefanRRichter commented on a change in pull request #7188: [FLINK-10473][State TTL] TTL state incremental cleanup for heap backend URL: https://github.com/apache/flink/pull/7188#discussion_r246774009
########## File path: flink-runtime/src/main/java/org/apache/flink/runtime/state/ttl/TtlIncrementalCleanup.java ########## @@ -0,0 +1,136 @@ +/* + * 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.runtime.state.ttl; + +import org.apache.flink.api.java.tuple.Tuple2; +import org.apache.flink.runtime.state.KeyedStateBackend; +import org.apache.flink.util.CloseableIterator; +import org.apache.flink.util.FlinkRuntimeException; + +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +import javax.annotation.Nonnegative; +import javax.annotation.Nonnull; + +import java.util.ConcurrentModificationException; + +/** + * Incremental cleanup of state with TTL. + * + * @param <K> type of state key + * @param <N> type of state namespace + */ +class TtlIncrementalCleanup<K, N> { + private static final Logger LOG = LoggerFactory.getLogger(TtlIncrementalCleanup.class); + + @Nonnegative + private final int cleanupSize; + + @Nonnull + private final KeyedStateBackend<K> keyContext; + + private AbstractTtlState<K, N, ?, ?, ?> ttlState; + private CloseableIterator<Tuple2<N, K>> keyNamespaceIterator; + private boolean suppressCallback; + + /** + * TtlIncrementalCleanup constructor. + * + * @param cleanupSize max number of queued keys to incrementally cleanup upon state access + * @param keyContext state backend to switch keys for cleanup + */ + TtlIncrementalCleanup(@Nonnegative int cleanupSize, @Nonnull KeyedStateBackend<K> keyContext) { + this.cleanupSize = cleanupSize; + this.keyContext = keyContext; + this.suppressCallback = false; + } + + void stateAccessed() { + // key is changed during cleanup, but this should not be called recursively in this case + if (suppressCallback) { + return; + } + suppressCallback = true; + initIteratorIfNot(); + K currentKey = keyContext.getCurrentKey(); + N currentNamespace = ttlState.getCurrentNamespace(); + try { + runCleanup(); + } catch (ConcurrentModificationException e) { Review comment: Do we want to catch this exception? I think the iterator has to tolerate concurrent modification or else this will basically happen all the time, right? ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: us...@infra.apache.org With regards, Apache Git Services
