nicktelford commented on code in PR #20022: URL: https://github.com/apache/kafka/pull/20022#discussion_r2167210497
########## streams/src/main/java/org/apache/kafka/streams/internals/metrics/OpenIterators.java: ########## @@ -0,0 +1,73 @@ +/* + * 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.internals.metrics; + +import org.apache.kafka.common.MetricName; +import org.apache.kafka.streams.processor.TaskId; +import org.apache.kafka.streams.processor.internals.metrics.StreamsMetricsImpl; +import org.apache.kafka.streams.state.internals.MeteredIterator; +import org.apache.kafka.streams.state.internals.metrics.StateStoreMetrics; + +import java.util.Comparator; +import java.util.NavigableSet; +import java.util.concurrent.ConcurrentSkipListSet; +import java.util.concurrent.atomic.LongAdder; + +public class OpenIterators { + private final TaskId taskId; + private final String metricsScope; + private final String name; + private final StreamsMetricsImpl streamsMetrics; + + private final LongAdder numOpenIterators = new LongAdder(); + private final NavigableSet<MeteredIterator> openIterators = new ConcurrentSkipListSet<>(Comparator.comparingLong(MeteredIterator::startTimestamp)); + + private MetricName metricName; + + public OpenIterators(final TaskId taskId, + final String metricsScope, + final String name, + final StreamsMetricsImpl streamsMetrics) { + this.taskId = taskId; + this.metricsScope = metricsScope; + this.name = name; + this.streamsMetrics = streamsMetrics; + } + + public void add(final MeteredIterator iterator) { + openIterators.add(iterator); + numOpenIterators.increment(); Review Comment: I'm not certain, but it's possible the `LongAdder` and `Set` duplicating the counting functionality is just an oversight. In theory, using the `LongAdder` would yield improved performance vs. `openIterators.size()`, however, in practice the total number of open iterators is not likely to be large enough to be a problem, so it seems reasonable to remove `numOpenIterators`. -- 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: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
