Merge pull request #518 from metamx/server-select

Smarter server selection at the broker level

server/src/main/java/io/druid/client/BrokerServerView.java

@@ -27,7 +27,7 @@ import com.metamx.common.logger.Logger;
 import com.metamx.http.client.HttpClient;
 import io.druid.client.selector.QueryableDruidServer;
 import io.druid.client.selector.ServerSelector;
-import io.druid.client.selector.ServerSelectorStrategy;
+import io.druid.client.selector.TierSelectorStrategy;
 import io.druid.concurrent.Execs;
 import io.druid.guice.annotations.Client;
 import io.druid.query.DataSource;
@@ -61,7 +61,7 @@ public class BrokerServerView implements TimelineServerView
   private final ObjectMapper smileMapper;
   private final HttpClient httpClient;
   private final ServerView baseView;
-  private final ServerSelectorStrategy serverSelectorStrategy;
+  private final TierSelectorStrategy tierSelectorStrategy;
 
   @Inject
   public BrokerServerView(
@@ -69,14 +69,14 @@ public class BrokerServerView implements TimelineServerView
       ObjectMapper smileMapper,
       @Client HttpClient httpClient,
       ServerView baseView,
-      ServerSelectorStrategy serverSelectorStrategy
+      TierSelectorStrategy tierSelectorStrategy
   )
   {
     this.warehouse = warehouse;
     this.smileMapper = smileMapper;
     this.httpClient = httpClient;
     this.baseView = baseView;
-    this.serverSelectorStrategy = serverSelectorStrategy;
+    this.tierSelectorStrategy = tierSelectorStrategy;
 
     this.clients = Maps.newConcurrentMap();
     this.selectors = Maps.newHashMap();
@@ -171,7 +171,7 @@ public class BrokerServerView implements TimelineServerView
 
       ServerSelector selector = selectors.get(segmentId);
       if (selector == null) {
-        selector = new ServerSelector(segment, serverSelectorStrategy);
+        selector = new ServerSelector(segment, tierSelectorStrategy);
 
         VersionedIntervalTimeline<String, ServerSelector> timeline = timelines.get(segment.getDataSource());
         if (timeline == null) {

server/src/main/java/io/druid/client/selector/AbstractTierSelectorStrategy.java

@@ -0,0 +1,62 @@
+/*
+ * Druid - a distributed column store.
+ * Copyright (C) 2012, 2013  Metamarkets Group Inc.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+
+package io.druid.client.selector;
+
+import com.metamx.common.ISE;
+import io.druid.timeline.DataSegment;
+
+import java.util.Comparator;
+import java.util.Map;
+import java.util.Set;
+import java.util.TreeMap;
+
+/**
+ */
+public abstract class AbstractTierSelectorStrategy implements TierSelectorStrategy
+{
+  private final ServerSelectorStrategy serverSelectorStrategy;
+
+  public AbstractTierSelectorStrategy(ServerSelectorStrategy serverSelectorStrategy)
+  {
+    this.serverSelectorStrategy = serverSelectorStrategy;
+  }
+
+  @Override
+  public QueryableDruidServer pick(
+      TreeMap<Integer, Set<QueryableDruidServer>> prioritizedServers, DataSegment segment
+  )
+  {
+    final Map.Entry<Integer, Set<QueryableDruidServer>> priorityServers = prioritizedServers.pollFirstEntry();
+
+    if (priorityServers == null) {
+      return null;
+    }
+
+    final Set<QueryableDruidServer> servers = priorityServers.getValue();
+    switch (servers.size()) {
+      case 0:
+        throw new ISE("[%s] Something hella weird going on here. We should not be here", segment.getIdentifier());
+      case 1:
+        return priorityServers.getValue().iterator().next();
+      default:
+        return serverSelectorStrategy.pick(servers, segment);
+    }
+  }
+}

server/src/main/java/io/druid/client/selector/ConnectionCountServerSelectorStrategy.java

@@ -20,14 +20,11 @@
 package io.druid.client.selector;
 
 import com.google.common.primitives.Ints;
-import com.metamx.common.ISE;
 import io.druid.timeline.DataSegment;
 
 import java.util.Collections;
 import java.util.Comparator;
-import java.util.Map;
 import java.util.Set;
-import java.util.TreeMap;
 
 public class ConnectionCountServerSelectorStrategy implements ServerSelectorStrategy
 {
@@ -41,25 +38,8 @@ public class ConnectionCountServerSelectorStrategy implements ServerSelectorStra
   };
 
   @Override
-  public QueryableDruidServer pick(
-      TreeMap<Integer, Set<QueryableDruidServer>> prioritizedServers, DataSegment segment
-  )
+  public QueryableDruidServer pick(Set<QueryableDruidServer> servers, DataSegment segment)
   {
-    final Map.Entry<Integer, Set<QueryableDruidServer>> highestPriorityServers = prioritizedServers.pollLastEntry();
-
-    if (highestPriorityServers == null) {
-      return null;
-    }
-
-    final Set<QueryableDruidServer> servers = highestPriorityServers.getValue();
-    final int size = servers.size();
-    switch (size) {
-      case 0:
-        throw new ISE("[%s] Something hella weird going on here. We should not be here", segment.getIdentifier());
-      case 1:
-        return highestPriorityServers.getValue().iterator().next();
-      default:
     return Collections.min(servers, comparator);
   }
 }
-}

server/src/main/java/io/druid/client/selector/CustomTierSelectorStrategy.java

@@ -0,0 +1,48 @@
+package io.druid.client.selector;
+
+import com.google.api.client.util.Maps;
+import com.google.common.primitives.Ints;
+import com.google.inject.Inject;
+
+import java.util.Comparator;
+import java.util.Map;
+
+/**
+ */
+public class CustomTierSelectorStrategy extends AbstractTierSelectorStrategy
+{
+  private final Comparator<Integer> comparator;
+
+  @Inject
+  public CustomTierSelectorStrategy(
+      ServerSelectorStrategy serverSelectorStrategy,
+      CustomTierSelectorStrategyConfig config
+  )
+  {
+    super(serverSelectorStrategy);
+
+    final Map<Integer, Integer> lookup = Maps.newHashMap();
+    int pos = 0;
+    for (Integer integer : config.getPriorities()) {
+      lookup.put(integer, pos);
+      pos++;
+    }
+
+    this.comparator = new Comparator<Integer>()
+    {
+      @Override
+      public int compare(Integer o1, Integer o2)
+      {
+        int pos1 = lookup.get(o1);
+        int pos2 = lookup.get(o2);
+        return Ints.compare(pos1, pos2);
+      }
+    };
+  }
+
+  @Override
+  public Comparator<Integer> getComparator()
+  {
+    return comparator;
+  }
+}

server/src/main/java/io/druid/client/selector/CustomTierSelectorStrategyConfig.java

@@ -0,0 +1,38 @@
+/*
+ * Druid - a distributed column store.
+ * Copyright (C) 2012, 2013  Metamarkets Group Inc.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+
+package io.druid.client.selector;
+
+import com.fasterxml.jackson.annotation.JsonProperty;
+import com.google.api.client.util.Lists;
+
+import java.util.List;
+
+/**
+ */
+public class CustomTierSelectorStrategyConfig
+{
+  @JsonProperty
+  private List<Integer> priorities = Lists.newArrayList();
+
+  public List<Integer> getPriorities()
+  {
+    return priorities;
+  }
+}

server/src/main/java/io/druid/client/selector/HighestPriorityTierSelectorStrategy.java

@@ -0,0 +1,51 @@
+/*
+ * Druid - a distributed column store.
+ * Copyright (C) 2012, 2013  Metamarkets Group Inc.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+
+package io.druid.client.selector;
+
+import com.google.common.primitives.Ints;
+import com.google.inject.Inject;
+
+import java.util.Comparator;
+
+/**
+ */
+public class HighestPriorityTierSelectorStrategy extends AbstractTierSelectorStrategy
+{
+  private static final Comparator<Integer> comparator = new Comparator<Integer>()
+  {
+    @Override
+    public int compare(Integer o1, Integer o2)
+    {
+      return -Ints.compare(o1, o2);
+    }
+  };
+
+  @Inject
+  public HighestPriorityTierSelectorStrategy(ServerSelectorStrategy serverSelectorStrategy)
+  {
+    super(serverSelectorStrategy);
+  }
+
+  @Override
+  public Comparator<Integer> getComparator()
+  {
+    return comparator;
+  }
+}

server/src/main/java/io/druid/client/selector/LowestPriorityTierSelectorStrategy.java

@@ -0,0 +1,51 @@
+/*
+ * Druid - a distributed column store.
+ * Copyright (C) 2012, 2013  Metamarkets Group Inc.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+
+package io.druid.client.selector;
+
+import com.google.common.primitives.Ints;
+import com.google.inject.Inject;
+
+import java.util.Comparator;
+
+/**
+ */
+public class LowestPriorityTierSelectorStrategy extends AbstractTierSelectorStrategy
+{
+  private static final Comparator<Integer> comparator = new Comparator<Integer>()
+  {
+    @Override
+    public int compare(Integer o1, Integer o2)
+    {
+      return Ints.compare(o1, o2);
+    }
+  };
+
+  @Inject
+  public LowestPriorityTierSelectorStrategy(ServerSelectorStrategy serverSelectorStrategy)
+  {
+    super(serverSelectorStrategy);
+  }
+
+  @Override
+  public Comparator<Integer> getComparator()
+  {
+    return comparator;
+  }
+}

server/src/main/java/io/druid/client/selector/RandomServerSelectorStrategy.java

@@ -20,36 +20,18 @@
 package io.druid.client.selector;
 
 import com.google.common.collect.Iterators;
-import com.metamx.common.ISE;
 import io.druid.timeline.DataSegment;
 
-import java.util.Map;
 import java.util.Random;
 import java.util.Set;
-import java.util.TreeMap;
 
 public class RandomServerSelectorStrategy implements ServerSelectorStrategy
 {
   private static final Random random = new Random();
 
   @Override
-  public QueryableDruidServer pick(TreeMap<Integer, Set<QueryableDruidServer>> prioritizedServers, DataSegment segment)
+  public QueryableDruidServer pick(Set<QueryableDruidServer> servers, DataSegment segment)
   {
-    final Map.Entry<Integer, Set<QueryableDruidServer>> highestPriorityServers = prioritizedServers.pollLastEntry();
-
-    if (highestPriorityServers == null) {
-      return null;
-    }
-
-    final Set<QueryableDruidServer> servers = highestPriorityServers.getValue();
-    final int size = servers.size();
-    switch (size) {
-      case 0:
-        throw new ISE("[%s] Something hella weird going on here. We should not be here", segment.getIdentifier());
-      case 1:
-        return highestPriorityServers.getValue().iterator().next();
-      default:
-        return Iterators.get(servers.iterator(), random.nextInt(size));
-    }
+    return Iterators.get(servers.iterator(), random.nextInt(servers.size()));
   }
 }

server/src/main/java/io/druid/client/selector/ServerSelector.java

@@ -37,11 +37,11 @@ public class ServerSelector implements DiscoverySelector<QueryableDruidServer>
   private final Set<QueryableDruidServer> servers = Sets.newHashSet();
 
   private final DataSegment segment;
-  private final ServerSelectorStrategy strategy;
+  private final TierSelectorStrategy strategy;
 
   public ServerSelector(
       DataSegment segment,
-      ServerSelectorStrategy strategy
+      TierSelectorStrategy strategy
   )
   {
     this.segment = segment;
@@ -79,7 +79,7 @@ public class ServerSelector implements DiscoverySelector<QueryableDruidServer>
   public QueryableDruidServer pick()
   {
     synchronized (this) {
-      TreeMap<Integer, Set<QueryableDruidServer>> prioritizedServers = Maps.newTreeMap();
+      final TreeMap<Integer, Set<QueryableDruidServer>> prioritizedServers = new TreeMap<>(strategy.getComparator());
       for (QueryableDruidServer server : servers) {
         Set<QueryableDruidServer> theServers = prioritizedServers.get(server.getServer().getPriority());
         if (theServers == null) {

server/src/main/java/io/druid/client/selector/ServerSelectorStrategy.java

@@ -24,7 +24,6 @@ import com.fasterxml.jackson.annotation.JsonTypeInfo;
 import io.druid.timeline.DataSegment;
 
 import java.util.Set;
-import java.util.TreeMap;
 
 @JsonTypeInfo(use = JsonTypeInfo.Id.NAME, property = "type", defaultImpl = RandomServerSelectorStrategy.class)
 @JsonSubTypes(value = {
@@ -33,5 +32,5 @@ import java.util.TreeMap;
 })
 public interface ServerSelectorStrategy
 {
-  public QueryableDruidServer pick(TreeMap<Integer, Set<QueryableDruidServer>> prioritizedServers, DataSegment segment);
+  public QueryableDruidServer pick(Set<QueryableDruidServer> servers, DataSegment segment);
 }

server/src/main/java/io/druid/client/selector/TierSelectorStrategy.java

@@ -0,0 +1,43 @@
+/*
+ * Druid - a distributed column store.
+ * Copyright (C) 2012, 2013  Metamarkets Group Inc.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+
+package io.druid.client.selector;
+
+import com.fasterxml.jackson.annotation.JsonSubTypes;
+import com.fasterxml.jackson.annotation.JsonTypeInfo;
+import io.druid.timeline.DataSegment;
+
+import java.util.Comparator;
+import java.util.Set;
+import java.util.TreeMap;
+
+/**
+ */
+@JsonTypeInfo(use = JsonTypeInfo.Id.NAME, property = "type", defaultImpl = HighestPriorityTierSelectorStrategy.class)
+@JsonSubTypes(value = {
+    @JsonSubTypes.Type(name = "highestPriority", value = HighestPriorityTierSelectorStrategy.class),
+    @JsonSubTypes.Type(name = "lowestPriority", value = LowestPriorityTierSelectorStrategy.class),
+    @JsonSubTypes.Type(name = "custom", value = CustomTierSelectorStrategy.class)
+})
+public interface TierSelectorStrategy
+{
+  public Comparator<Integer> getComparator();
+
+  public QueryableDruidServer pick(TreeMap<Integer, Set<QueryableDruidServer>> prioritizedServers, DataSegment segment);
+}

server/src/test/java/io/druid/client/CachingClusteredClientTest.java

@@ -38,6 +38,7 @@ import com.metamx.common.guava.nary.TrinaryFn;
 import io.druid.client.cache.Cache;
 import io.druid.client.cache.CacheConfig;
 import io.druid.client.cache.MapCache;
+import io.druid.client.selector.HighestPriorityTierSelectorStrategy;
 import io.druid.client.selector.QueryableDruidServer;
 import io.druid.client.selector.RandomServerSelectorStrategy;
 import io.druid.client.selector.ServerSelector;
@@ -585,7 +586,8 @@ public class CachingClusteredClientTest
   }
 
   @Test
-  public  void testTopNOnPostAggMetricCaching() {
+  public void testTopNOnPostAggMetricCaching()
+  {
     final TopNQueryBuilder builder = new TopNQueryBuilder()
         .dataSource(DATA_SOURCE)
         .dimension(TOP_DIM)
@@ -914,7 +916,10 @@ public class CachingClusteredClientTest
         );
         serverExpectations.get(lastServer).addExpectation(expectation);
 
-        ServerSelector selector = new ServerSelector(expectation.getSegment(), new RandomServerSelectorStrategy());
+        ServerSelector selector = new ServerSelector(
+            expectation.getSegment(),
+            new HighestPriorityTierSelectorStrategy(new RandomServerSelectorStrategy())
+        );
         selector.addServer(new QueryableDruidServer(lastServer, null));
 
         final PartitionChunk<ServerSelector> chunk;

server/src/test/java/io/druid/client/DirectDruidClientTest.java

@@ -28,6 +28,7 @@ import com.metamx.http.client.HttpClient;
 import com.metamx.http.client.Request;
 import com.metamx.http.client.RequestBuilder;
 import io.druid.client.selector.ConnectionCountServerSelectorStrategy;
+import io.druid.client.selector.HighestPriorityTierSelectorStrategy;
 import io.druid.client.selector.QueryableDruidServer;
 import io.druid.client.selector.ServerSelector;
 import io.druid.jackson.DefaultObjectMapper;
@@ -87,7 +88,7 @@ public class DirectDruidClientTest
             0,
             0L
         ),
-        new ConnectionCountServerSelectorStrategy()
+        new HighestPriorityTierSelectorStrategy(new ConnectionCountServerSelectorStrategy())
     );
 
     DirectDruidClient client1 = new DirectDruidClient(

services/src/main/java/io/druid/cli/CliBroker.java

@@ -31,7 +31,9 @@ import io.druid.client.cache.Cache;
 import io.druid.client.cache.CacheConfig;
 import io.druid.client.cache.CacheMonitor;
 import io.druid.client.cache.CacheProvider;
+import io.druid.client.selector.CustomTierSelectorStrategyConfig;
 import io.druid.client.selector.ServerSelectorStrategy;
+import io.druid.client.selector.TierSelectorStrategy;
 import io.druid.curator.discovery.DiscoveryModule;
 import io.druid.guice.Jerseys;
 import io.druid.guice.JsonConfigProvider;
@@ -83,7 +85,9 @@ public class CliBroker extends ServerRunnable
             binder.bind(Cache.class).toProvider(CacheProvider.class).in(ManageLifecycle.class);
             JsonConfigProvider.bind(binder, "druid.broker.cache", CacheProvider.class);
             JsonConfigProvider.bind(binder, "druid.broker.cache", CacheConfig.class);
-            JsonConfigProvider.bind(binder, "druid.broker.balancer", ServerSelectorStrategy.class);
+            JsonConfigProvider.bind(binder, "druid.broker.select.tier", TierSelectorStrategy.class);
+            JsonConfigProvider.bind(binder, "druid.broker.select.tier.custom", CustomTierSelectorStrategyConfig.class);
+            JsonConfigProvider.bind(binder, "druid.broker.select.server", ServerSelectorStrategy.class);
 
             binder.bind(QuerySegmentWalker.class).to(ClientQuerySegmentWalker.class).in(LazySingleton.class);