madrob commented on a change in pull request #1606: URL: https://github.com/apache/lucene-solr/pull/1606#discussion_r444952555
########## File path: solr/core/src/java/org/apache/solr/util/circuitbreaker/MemoryCircuitBreaker.java ########## @@ -0,0 +1,88 @@ +/* + * 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.solr.util.circuitbreaker; + +import java.lang.management.ManagementFactory; +import java.lang.management.MemoryMXBean; + +import org.apache.solr.core.SolrCore; + +public class MemoryCircuitBreaker extends CircuitBreaker { + private static final MemoryMXBean MEMORY_MX_BEAN = ManagementFactory.getMemoryMXBean(); + + // Assumption -- the value of these parameters will be set correctly before invoking printDebugInfo() + private double seenMemory; + private double allowedMemory; + + public MemoryCircuitBreaker(SolrCore solrCore) { + super(solrCore); + } + + // TODO: An optimization can be to trip the circuit breaker for a duration of time + // after the circuit breaker condition is matched. This will optimize for per call + // overhead of calculating the condition parameters but can result in false positives. + @Override + public boolean isCircuitBreakerGauntletTripped() { + if (!isCircuitBreakerEnabled()) { + return false; + } + + allowedMemory = getCurrentMemoryThreshold(); + + if (allowedMemory < 0) { + // No threshold + return false; + } + + seenMemory = calculateLiveMemoryUsage(); + + return (seenMemory >= allowedMemory); + } + + @Override + public String printDebugInfo() { + return "seen memory " + seenMemory + " allowed memory " + allowedMemory; + } + + private double getCurrentMemoryThreshold() { + int thresholdValueInPercentage = solrCore.getSolrConfig().memoryCircuitBreakerThreshold; + long currentMaxHeap = MEMORY_MX_BEAN.getHeapMemoryUsage().getMax(); + + if (currentMaxHeap <= 0) { + return Long.MIN_VALUE; + } + + double thresholdInFraction = (double) thresholdValueInPercentage / 100; + double actualLimit = currentMaxHeap * thresholdInFraction; + + if (actualLimit <= 0) { + throw new IllegalStateException("Memory limit cannot be less than or equal to zero"); + } + + return actualLimit; + } + + /** + * Calculate the live memory usage for the system. This method has package visibility + * to allow using for testing + * @return Memory usage in bytes + */ + protected long calculateLiveMemoryUsage() { + return MEMORY_MX_BEAN.getHeapMemoryUsage().getUsed(); Review comment: Yea, add some comments to this effect to the code so that if people run into issues with it they can more easily figure out what's up without having to find the comments from this PR. ---------------------------------------------------------------- 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. For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: issues-unsubscr...@lucene.apache.org For additional commands, e-mail: issues-h...@lucene.apache.org
