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| 1 | +/* |
| 2 | + * Licensed to Elasticsearch under one or more contributor |
| 3 | + * license agreements. See the NOTICE file distributed with |
| 4 | + * this work for additional information regarding copyright |
| 5 | + * ownership. Elasticsearch licenses this file to you under |
| 6 | + * the Apache License, Version 2.0 (the "License"); you may |
| 7 | + * not use this file except in compliance with the License. |
| 8 | + * You may obtain a copy of the License at |
| 9 | + * |
| 10 | + * http://www.apache.org/licenses/LICENSE-2.0 |
| 11 | + * |
| 12 | + * Unless required by applicable law or agreed to in writing, |
| 13 | + * software distributed under the License is distributed on an |
| 14 | + * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY |
| 15 | + * KIND, either express or implied. See the License for the |
| 16 | + * specific language governing permissions and limitations |
| 17 | + * under the License. |
| 18 | + */ |
| 19 | + |
| 20 | +package org.elasticsearch.common.breaker; |
| 21 | + |
| 22 | +import org.elasticsearch.common.logging.ESLogger; |
| 23 | +import org.elasticsearch.common.unit.ByteSizeValue; |
| 24 | +import org.elasticsearch.indices.breaker.BreakerSettings; |
| 25 | +import org.elasticsearch.indices.breaker.HierarchyCircuitBreakerService; |
| 26 | + |
| 27 | +import java.util.concurrent.atomic.AtomicLong; |
| 28 | + |
| 29 | +/** |
| 30 | + * Breaker that will check a parent's when incrementing |
| 31 | + */ |
| 32 | +public class ChildMemoryCircuitBreaker implements CircuitBreaker { |
| 33 | + |
| 34 | + private final long memoryBytesLimit; |
| 35 | + private final BreakerSettings settings; |
| 36 | + private final double overheadConstant; |
| 37 | + private final AtomicLong used; |
| 38 | + private final AtomicLong trippedCount; |
| 39 | + private final ESLogger logger; |
| 40 | + private final HierarchyCircuitBreakerService parent; |
| 41 | + private final Name name; |
| 42 | + |
| 43 | + /** |
| 44 | + * Create a circuit breaker that will break if the number of estimated |
| 45 | + * bytes grows above the limit. All estimations will be multiplied by |
| 46 | + * the given overheadConstant. This breaker starts with 0 bytes used. |
| 47 | + * @param settings settings to configure this breaker |
| 48 | + * @param parent parent circuit breaker service to delegate tripped breakers to |
| 49 | + * @param name the name of the breaker |
| 50 | + */ |
| 51 | + public ChildMemoryCircuitBreaker(BreakerSettings settings, ESLogger logger, |
| 52 | + HierarchyCircuitBreakerService parent, Name name) { |
| 53 | + this(settings, null, logger, parent, name); |
| 54 | + } |
| 55 | + |
| 56 | + /** |
| 57 | + * Create a circuit breaker that will break if the number of estimated |
| 58 | + * bytes grows above the limit. All estimations will be multiplied by |
| 59 | + * the given overheadConstant. Uses the given oldBreaker to initialize |
| 60 | + * the starting offset. |
| 61 | + * @param settings settings to configure this breaker |
| 62 | + * @param parent parent circuit breaker service to delegate tripped breakers to |
| 63 | + * @param name the name of the breaker |
| 64 | + * @param oldBreaker the previous circuit breaker to inherit the used value from (starting offset) |
| 65 | + */ |
| 66 | + public ChildMemoryCircuitBreaker(BreakerSettings settings, ChildMemoryCircuitBreaker oldBreaker, |
| 67 | + ESLogger logger, HierarchyCircuitBreakerService parent, Name name) { |
| 68 | + this.name = name; |
| 69 | + this.settings = settings; |
| 70 | + this.memoryBytesLimit = settings.getLimit(); |
| 71 | + this.overheadConstant = settings.getOverhead(); |
| 72 | + if (oldBreaker == null) { |
| 73 | + this.used = new AtomicLong(0); |
| 74 | + this.trippedCount = new AtomicLong(0); |
| 75 | + } else { |
| 76 | + this.used = oldBreaker.used; |
| 77 | + this.trippedCount = oldBreaker.trippedCount; |
| 78 | + } |
| 79 | + this.logger = logger; |
| 80 | + if (logger.isTraceEnabled()) { |
| 81 | + logger.trace("creating ChildCircuitBreaker with settings {}", this.settings); |
| 82 | + } |
| 83 | + this.parent = parent; |
| 84 | + } |
| 85 | + |
| 86 | + /** |
| 87 | + * Method used to trip the breaker, delegates to the parent to determine |
| 88 | + * whether to trip the breaker or not |
| 89 | + */ |
| 90 | + @Override |
| 91 | + public void circuitBreak(String fieldName, long bytesNeeded) { |
| 92 | + this.trippedCount.incrementAndGet(); |
| 93 | + throw new CircuitBreakingException("[" + this.name + "] Data too large, data for [" + |
| 94 | + fieldName + "] would be larger than limit of [" + |
| 95 | + memoryBytesLimit + "/" + new ByteSizeValue(memoryBytesLimit) + "]", |
| 96 | + bytesNeeded, this.memoryBytesLimit); |
| 97 | + } |
| 98 | + |
| 99 | + /** |
| 100 | + * Add a number of bytes, tripping the circuit breaker if the aggregated |
| 101 | + * estimates are above the limit. Automatically trips the breaker if the |
| 102 | + * memory limit is set to 0. Will never trip the breaker if the limit is |
| 103 | + * set < 0, but can still be used to aggregate estimations. |
| 104 | + * @param bytes number of bytes to add to the breaker |
| 105 | + * @return number of "used" bytes so far |
| 106 | + * @throws CircuitBreakingException |
| 107 | + */ |
| 108 | + @Override |
| 109 | + public double addEstimateBytesAndMaybeBreak(long bytes, String label) throws CircuitBreakingException { |
| 110 | + // short-circuit on no data allowed, immediately throwing an exception |
| 111 | + if (memoryBytesLimit == 0) { |
| 112 | + circuitBreak(label, bytes); |
| 113 | + } |
| 114 | + |
| 115 | + long newUsed; |
| 116 | + // If there is no limit (-1), we can optimize a bit by using |
| 117 | + // .addAndGet() instead of looping (because we don't have to check a |
| 118 | + // limit), which makes the RamAccountingTermsEnum case faster. |
| 119 | + if (this.memoryBytesLimit == -1) { |
| 120 | + newUsed = this.used.addAndGet(bytes); |
| 121 | + if (logger.isTraceEnabled()) { |
| 122 | + logger.trace("[{}] Adding [{}][{}] to used bytes [new used: [{}], limit: [-1b]]", |
| 123 | + this.name, new ByteSizeValue(bytes), label, new ByteSizeValue(newUsed)); |
| 124 | + } |
| 125 | + } else { |
| 126 | + // Otherwise, check the addition and commit the addition, looping if |
| 127 | + // there are conflicts. May result in additional logging, but it's |
| 128 | + // trace logging and shouldn't be counted on for additions. |
| 129 | + long currentUsed; |
| 130 | + do { |
| 131 | + currentUsed = this.used.get(); |
| 132 | + newUsed = currentUsed + bytes; |
| 133 | + long newUsedWithOverhead = (long) (newUsed * overheadConstant); |
| 134 | + if (logger.isTraceEnabled()) { |
| 135 | + logger.trace("[{}] Adding [{}][{}] to used bytes [new used: [{}], limit: {} [{}], estimate: {} [{}]]", |
| 136 | + this.name, |
| 137 | + new ByteSizeValue(bytes), label, new ByteSizeValue(newUsed), |
| 138 | + memoryBytesLimit, new ByteSizeValue(memoryBytesLimit), |
| 139 | + newUsedWithOverhead, new ByteSizeValue(newUsedWithOverhead)); |
| 140 | + } |
| 141 | + if (memoryBytesLimit > 0 && newUsedWithOverhead > memoryBytesLimit) { |
| 142 | + logger.error("[{}] New used memory {} [{}] from field [{}] would be larger than configured breaker: {} [{}], breaking", |
| 143 | + this.name, |
| 144 | + newUsedWithOverhead, new ByteSizeValue(newUsedWithOverhead), label, |
| 145 | + memoryBytesLimit, new ByteSizeValue(memoryBytesLimit)); |
| 146 | + circuitBreak(label, newUsedWithOverhead); |
| 147 | + } |
| 148 | + // Attempt to set the new used value, but make sure it hasn't changed |
| 149 | + // underneath us, if it has, keep trying until we are able to set it |
| 150 | + } while (!this.used.compareAndSet(currentUsed, newUsed)); |
| 151 | + } |
| 152 | + |
| 153 | + // Additionally, we need to check that we haven't exceeded the parent's limit |
| 154 | + try { |
| 155 | + parent.checkParentLimit(label); |
| 156 | + } catch (CircuitBreakingException e) { |
| 157 | + // If the parent breaker is tripped, this breaker has to be |
| 158 | + // adjusted back down because the allocation is "blocked" but the |
| 159 | + // breaker has already been incremented |
| 160 | + this.used.addAndGet(-bytes); |
| 161 | + throw e; |
| 162 | + } |
| 163 | + return newUsed; |
| 164 | + } |
| 165 | + |
| 166 | + /** |
| 167 | + * Add an <b>exact</b> number of bytes, not checking for tripping the |
| 168 | + * circuit breaker. This bypasses the overheadConstant multiplication. |
| 169 | + * |
| 170 | + * Also does not check with the parent breaker to see if the parent limit |
| 171 | + * has been exceeded. |
| 172 | + * |
| 173 | + * @param bytes number of bytes to add to the breaker |
| 174 | + * @return number of "used" bytes so far |
| 175 | + */ |
| 176 | + @Override |
| 177 | + public long addWithoutBreaking(long bytes) { |
| 178 | + long u = used.addAndGet(bytes); |
| 179 | + if (logger.isTraceEnabled()) { |
| 180 | + logger.trace("[{}] Adjusted breaker by [{}] bytes, now [{}]", this.name, bytes, u); |
| 181 | + } |
| 182 | + assert u >= 0 : "Used bytes: [" + u + "] must be >= 0"; |
| 183 | + return u; |
| 184 | + } |
| 185 | + |
| 186 | + /** |
| 187 | + * @return the number of aggregated "used" bytes so far |
| 188 | + */ |
| 189 | + @Override |
| 190 | + public long getUsed() { |
| 191 | + return this.used.get(); |
| 192 | + } |
| 193 | + |
| 194 | + /** |
| 195 | + * @return the number of bytes that can be added before the breaker trips |
| 196 | + */ |
| 197 | + @Override |
| 198 | + public long getLimit() { |
| 199 | + return this.memoryBytesLimit; |
| 200 | + } |
| 201 | + |
| 202 | + /** |
| 203 | + * @return the constant multiplier the breaker uses for aggregations |
| 204 | + */ |
| 205 | + @Override |
| 206 | + public double getOverhead() { |
| 207 | + return this.overheadConstant; |
| 208 | + } |
| 209 | + |
| 210 | + /** |
| 211 | + * @return the number of times the breaker has been tripped |
| 212 | + */ |
| 213 | + @Override |
| 214 | + public long getTrippedCount() { |
| 215 | + return this.trippedCount.get(); |
| 216 | + } |
| 217 | + |
| 218 | + /** |
| 219 | + * @return the name of the breaker |
| 220 | + */ |
| 221 | + public Name getName() { |
| 222 | + return this.name; |
| 223 | + } |
| 224 | +} |
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