diff --git a/server/src/main/java/org/apache/druid/server/coordinator/balancer/BalancerStrategyFactory.java b/server/src/main/java/org/apache/druid/server/coordinator/balancer/BalancerStrategyFactory.java index f27341fd3e0b..d0d426f7b51c 100644 --- a/server/src/main/java/org/apache/druid/server/coordinator/balancer/BalancerStrategyFactory.java +++ b/server/src/main/java/org/apache/druid/server/coordinator/balancer/BalancerStrategyFactory.java @@ -26,7 +26,7 @@ @JsonTypeInfo(use = JsonTypeInfo.Id.NAME, property = "strategy", defaultImpl = CostBalancerStrategyFactory.class) @JsonSubTypes(value = { @JsonSubTypes.Type(name = "cost", value = CostBalancerStrategyFactory.class), - @JsonSubTypes.Type(name = "cachingCost", value = CachingCostBalancerStrategyFactory.class), + @JsonSubTypes.Type(name = "cachingCost", value = DisabledCachingCostBalancerStrategyFactory.class), @JsonSubTypes.Type(name = "diskNormalized", value = DiskNormalizedCostBalancerStrategyFactory.class), @JsonSubTypes.Type(name = "random", value = RandomBalancerStrategyFactory.class) }) diff --git a/server/src/main/java/org/apache/druid/server/coordinator/balancer/CachingCostBalancerStrategy.java b/server/src/main/java/org/apache/druid/server/coordinator/balancer/CachingCostBalancerStrategy.java index eda99289157f..64d77842e3de 100644 --- a/server/src/main/java/org/apache/druid/server/coordinator/balancer/CachingCostBalancerStrategy.java +++ b/server/src/main/java/org/apache/druid/server/coordinator/balancer/CachingCostBalancerStrategy.java @@ -28,6 +28,11 @@ import java.util.Collections; import java.util.Set; +/** + * @deprecated This is currently being used only in tests for benchmarking purposes + * and will be removed in future releases. + */ +@Deprecated public class CachingCostBalancerStrategy extends CostBalancerStrategy { private final ClusterCostCache clusterCostCache; diff --git a/server/src/main/java/org/apache/druid/server/coordinator/balancer/CachingCostBalancerStrategyFactory.java b/server/src/main/java/org/apache/druid/server/coordinator/balancer/CachingCostBalancerStrategyFactory.java index 0ddacaead705..89b7cf754633 100644 --- a/server/src/main/java/org/apache/druid/server/coordinator/balancer/CachingCostBalancerStrategyFactory.java +++ b/server/src/main/java/org/apache/druid/server/coordinator/balancer/CachingCostBalancerStrategyFactory.java @@ -39,6 +39,11 @@ import java.util.concurrent.ExecutorService; import java.util.concurrent.RejectedExecutionException; +/** + * @deprecated This is currently being used only in tests for benchmarking purposes + * and will be removed in future releases. + */ +@Deprecated public class CachingCostBalancerStrategyFactory implements BalancerStrategyFactory { private static final EmittingLogger LOG = new EmittingLogger(CachingCostBalancerStrategyFactory.class); diff --git a/server/src/main/java/org/apache/druid/server/coordinator/balancer/CostBalancerStrategyFactory.java b/server/src/main/java/org/apache/druid/server/coordinator/balancer/CostBalancerStrategyFactory.java index 3085f35b6b87..10d5952390a8 100644 --- a/server/src/main/java/org/apache/druid/server/coordinator/balancer/CostBalancerStrategyFactory.java +++ b/server/src/main/java/org/apache/druid/server/coordinator/balancer/CostBalancerStrategyFactory.java @@ -24,7 +24,7 @@ public class CostBalancerStrategyFactory implements BalancerStrategyFactory { @Override - public CostBalancerStrategy createBalancerStrategy(ListeningExecutorService exec) + public BalancerStrategy createBalancerStrategy(ListeningExecutorService exec) { return new CostBalancerStrategy(exec); } diff --git a/server/src/main/java/org/apache/druid/server/coordinator/balancer/DisabledCachingCostBalancerStrategyFactory.java b/server/src/main/java/org/apache/druid/server/coordinator/balancer/DisabledCachingCostBalancerStrategyFactory.java new file mode 100644 index 000000000000..7d2f0d96bc67 --- /dev/null +++ b/server/src/main/java/org/apache/druid/server/coordinator/balancer/DisabledCachingCostBalancerStrategyFactory.java @@ -0,0 +1,35 @@ +/* + * 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.druid.server.coordinator.balancer; + +import com.google.common.util.concurrent.ListeningExecutorService; +import org.apache.druid.java.util.common.logger.Logger; + +public class DisabledCachingCostBalancerStrategyFactory implements BalancerStrategyFactory +{ + private static final Logger log = new Logger(BalancerStrategyFactory.class); + + @Override + public BalancerStrategy createBalancerStrategy(ListeningExecutorService exec) + { + log.warn("Balancer strategy 'cachingCost' is disabled. Using 'cost' strategy instead."); + return new CostBalancerStrategy(exec); + } +} diff --git a/server/src/main/java/org/apache/druid/server/coordinator/balancer/DiskNormalizedCostBalancerStrategy.java b/server/src/main/java/org/apache/druid/server/coordinator/balancer/DiskNormalizedCostBalancerStrategy.java index 601e5b042e0f..1d16c4785b56 100644 --- a/server/src/main/java/org/apache/druid/server/coordinator/balancer/DiskNormalizedCostBalancerStrategy.java +++ b/server/src/main/java/org/apache/druid/server/coordinator/balancer/DiskNormalizedCostBalancerStrategy.java @@ -23,6 +23,23 @@ import org.apache.druid.server.coordinator.ServerHolder; import org.apache.druid.timeline.DataSegment; +/** + * A {@link BalancerStrategy} which can be used when historicals in a tier have + * varying disk capacities. This strategy normalizes the cost of placing a segment on + * a server as calculated by {@link CostBalancerStrategy} by doing the following: + * + * i.e. to place a segment on a given server + * 
+ * cost = as computed by CostBalancerStrategy
+ * normalizedCost = (cost / numSegments) * usageRatio
+ *                = (cost / numSegments) * (diskUsed / totalDiskSpace)
+ *
+ */ public class DiskNormalizedCostBalancerStrategy extends CostBalancerStrategy { public DiskNormalizedCostBalancerStrategy(ListeningExecutorService exec) @@ -30,10 +47,6 @@ public DiskNormalizedCostBalancerStrategy(ListeningExecutorService exec) super(exec); } - /** - * Averages the cost obtained from CostBalancerStrategy. Also the costs are weighted according to their usage ratios. - * This ensures that all the hosts will have the same % disk utilization. - */ @Override protected double computePlacementCost( final DataSegment proposalSegment, diff --git a/server/src/test/java/org/apache/druid/server/coordinator/balancer/BalancerStrategyFactoryTest.java b/server/src/test/java/org/apache/druid/server/coordinator/balancer/BalancerStrategyFactoryTest.java new file mode 100644 index 000000000000..d08b8ff104e5 --- /dev/null +++ b/server/src/test/java/org/apache/druid/server/coordinator/balancer/BalancerStrategyFactoryTest.java @@ -0,0 +1,63 @@ +/* + * 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.druid.server.coordinator.balancer; + +import com.fasterxml.jackson.core.JsonProcessingException; +import com.fasterxml.jackson.databind.ObjectMapper; +import com.google.common.util.concurrent.ListeningExecutorService; +import com.google.common.util.concurrent.MoreExecutors; +import org.apache.druid.segment.TestHelper; +import org.apache.druid.server.coordinator.simulate.BlockingExecutorService; +import org.junit.After; +import org.junit.Assert; +import org.junit.Before; +import org.junit.Test; + +public class BalancerStrategyFactoryTest +{ + private final ObjectMapper MAPPER = TestHelper.makeJsonMapper(); + + private ListeningExecutorService executorService; + + @Before + public void setup() + { + executorService = MoreExecutors.listeningDecorator( + new BlockingExecutorService("StrategyFactoryTest-%s") + ); + } + + @After + public void tearDown() + { + executorService.shutdownNow(); + } + + @Test + public void testCachingCostStrategyFallsBackToCost() throws JsonProcessingException + { + final String json = "{\"strategy\":\"cachingCost\"}"; + BalancerStrategyFactory factory = MAPPER.readValue(json, BalancerStrategyFactory.class); + BalancerStrategy strategy = factory.createBalancerStrategy(executorService); + + Assert.assertTrue(strategy instanceof CostBalancerStrategy); + Assert.assertFalse(strategy instanceof CachingCostBalancerStrategy); + } +}