murblanc commented on a change in pull request #1684: URL: https://github.com/apache/lucene-solr/pull/1684#discussion_r482485955
########## File path: solr/core/src/java/org/apache/solr/cluster/placement/plugins/SamplePluginMinimizeCores.java ########## @@ -0,0 +1,132 @@ +/* + * 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.cluster.placement.plugins; + +import java.util.ArrayList; +import java.util.Collections; +import java.util.Comparator; +import java.util.HashSet; +import java.util.Iterator; +import java.util.Set; +import java.util.Map; + +import com.google.common.collect.Ordering; +import com.google.common.collect.TreeMultimap; +import org.apache.solr.cluster.placement.Cluster; +import org.apache.solr.cluster.placement.CoresCountPropertyValue; +import org.apache.solr.cluster.placement.CreateNewCollectionPlacementRequest; +import org.apache.solr.cluster.placement.Node; +import org.apache.solr.cluster.placement.PlacementException; +import org.apache.solr.cluster.placement.PlacementPlugin; +import org.apache.solr.cluster.placement.PropertyKey; +import org.apache.solr.cluster.placement.PropertyKeyFactory; +import org.apache.solr.cluster.placement.PropertyValue; +import org.apache.solr.cluster.placement.PropertyValueFetcher; +import org.apache.solr.cluster.placement.Replica; +import org.apache.solr.cluster.placement.ReplicaPlacement; +import org.apache.solr.cluster.placement.PlacementRequest; +import org.apache.solr.cluster.placement.PlacementPlan; +import org.apache.solr.cluster.placement.PlacementPlanFactory; +import org.apache.solr.common.util.SuppressForbidden; + +/** + * Implements placing replicas to minimize number of cores per {@link Node}, while not placing two replicas of the same + * shard on the same node. + * + * TODO: code not tested and never run, there are no implementation yet for used interfaces + */ +public class SamplePluginMinimizeCores implements PlacementPlugin { + + @SuppressForbidden(reason = "Ordering.arbitrary() has no equivalent in Comparator class. Rather reuse than copy.") + public PlacementPlan computePlacement(Cluster cluster, PlacementRequest placementRequest, PropertyKeyFactory propertyFactory, + PropertyValueFetcher propertyFetcher, PlacementPlanFactory placementPlanFactory) throws PlacementException { + // This plugin only supports Creating a collection. + if (!(placementRequest instanceof CreateNewCollectionPlacementRequest)) { + throw new PlacementException("This toy plugin only supports creating collections"); + } + + final CreateNewCollectionPlacementRequest reqCreateCollection = (CreateNewCollectionPlacementRequest) placementRequest; + + final int totalReplicasPerShard = reqCreateCollection.getNrtReplicationFactor() + + reqCreateCollection.getTlogReplicationFactor() + reqCreateCollection.getPullReplicationFactor(); + + if (cluster.getLiveNodes().size() < totalReplicasPerShard) { + throw new PlacementException("Cluster size too small for number of replicas per shard"); + } + + // Get number of cores on each Node + TreeMultimap<Integer, Node> nodesByCores = TreeMultimap.create(Comparator.naturalOrder(), Ordering.arbitrary()); Review comment: I challenge the "drastically reduce" assertion here @sigram. I think we can save a couple or so lines of code per property type, but maybe not much more. We can likely simplify the `PropertyValue` hierarchy to a few typed abstractions, see section at the end of [this comment](https://github.com/apache/lucene-solr/pull/1684#issuecomment-684063923). If we do keep the efficiency of multi fetching (all properties from a node at once) and want to hide from the plugin implementer the ability to fetch from multiple nodes concurrently, we do need to keep this whole logic of keys totally describing what they refer to. ---------------------------------------------------------------- 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
