| /* |
| * 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.invoke.MethodHandles; |
| import java.lang.management.ManagementFactory; |
| import java.lang.management.MemoryMXBean; |
| |
| import org.slf4j.Logger; |
| import org.slf4j.LoggerFactory; |
| |
| /** |
| * <p> |
| * Tracks the current JVM heap usage and triggers if it exceeds the defined percentage of the maximum |
| * heap size allocated to the JVM. This circuit breaker is a part of the default CircuitBreakerManager |
| * so is checked for every request -- hence it is realtime. Once the memory usage goes below the threshold, |
| * it will start allowing queries again. |
| * </p> |
| * |
| * <p> |
| * The memory threshold is defined as a percentage of the maximum memory allocated -- see memoryCircuitBreakerThresholdPct |
| * in solrconfig.xml. |
| * </p> |
| */ |
| |
| public class MemoryCircuitBreaker extends CircuitBreaker { |
| private static final Logger log = LoggerFactory.getLogger(MethodHandles.lookup().lookupClass()); |
| private static final MemoryMXBean MEMORY_MX_BEAN = ManagementFactory.getMemoryMXBean(); |
| |
| private boolean enabled; |
| private final long heapMemoryThreshold; |
| |
| // Assumption -- the value of these parameters will be set correctly before invoking getDebugInfo() |
| private static final ThreadLocal<Long> seenMemory = ThreadLocal.withInitial(() -> 0L); |
| private static final ThreadLocal<Long> allowedMemory = ThreadLocal.withInitial(() -> 0L); |
| |
| public MemoryCircuitBreaker(CircuitBreakerConfig config) { |
| super(config); |
| |
| this.enabled = config.getMemCBEnabled(); |
| |
| long currentMaxHeap = MEMORY_MX_BEAN.getHeapMemoryUsage().getMax(); |
| |
| if (currentMaxHeap <= 0) { |
| throw new IllegalArgumentException("Invalid JVM state for the max heap usage"); |
| } |
| |
| int thresholdValueInPercentage = config.getMemCBThreshold(); |
| double thresholdInFraction = thresholdValueInPercentage / (double) 100; |
| heapMemoryThreshold = (long) (currentMaxHeap * thresholdInFraction); |
| |
| if (heapMemoryThreshold <= 0) { |
| throw new IllegalStateException("Memory limit cannot be less than or equal to zero"); |
| } |
| } |
| |
| // 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 isTripped() { |
| if (!isEnabled()) { |
| return false; |
| } |
| |
| if (!enabled) { |
| return false; |
| } |
| |
| long localAllowedMemory = getCurrentMemoryThreshold(); |
| long localSeenMemory = calculateLiveMemoryUsage(); |
| |
| allowedMemory.set(localAllowedMemory); |
| |
| seenMemory.set(localSeenMemory); |
| |
| return (localSeenMemory >= localAllowedMemory); |
| } |
| |
| @Override |
| public String getDebugInfo() { |
| if (seenMemory.get() == 0L || allowedMemory.get() == 0L) { |
| log.warn("MemoryCircuitBreaker's monitored values (seenMemory, allowedMemory) not set"); |
| } |
| |
| return "seenMemory=" + seenMemory.get() + " allowedMemory=" + allowedMemory.get(); |
| } |
| |
| @Override |
| public String getErrorMessage() { |
| return "Memory Circuit Breaker triggered as JVM heap usage values are greater than allocated threshold." + |
| "Seen JVM heap memory usage " + seenMemory.get() + " and allocated threshold " + |
| allowedMemory.get(); |
| } |
| |
| private long getCurrentMemoryThreshold() { |
| return heapMemoryThreshold; |
| } |
| |
| /** |
| * 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() { |
| // NOTE: MemoryUsageGaugeSet provides memory usage statistics but we do not use them |
| // here since it will require extra allocations and incur cost, hence it is cheaper to use |
| // MemoryMXBean directly. Ideally, this call should not add noticeable |
| // latency to a query -- but if it does, please signify on SOLR-14588 |
| return MEMORY_MX_BEAN.getHeapMemoryUsage().getUsed(); |
| } |
| } |