Improve alert message for segment assignments (#14696)

Changes:
- Add interface `SegmentDeleteHandler` for marking segments as unused
- In `StrategicSegmentAssigner`, collect all segments on which a drop rule applies in a list
- Process the list above as a batch delete rather than individual deletes
- Improve alert messages when an invalid tier is specified in a load rule
- Improve alert message when no rule applies on a segment

server/src/main/java/org/apache/druid/server/coordinator/DruidCoordinator.java

@@ -338,13 +338,6 @@ public class DruidCoordinator
     return CoordinatorCompactionConfig.current(configManager);
   }
 
-  public void markSegmentsAsUnused(String datasource, Set<SegmentId> segmentIds)
-  {
-    log.debug("Marking [%d] segments of datasource [%s] as unused.", segmentIds.size(), datasource);
-    int updatedCount = segmentsMetadataManager.markSegmentsAsUnused(segmentIds);
-    log.info("Successfully marked [%d] segments of datasource [%s] as unused.", updatedCount, datasource);
-  }
-
   public String getCurrentLeader()
   {
     return coordLeaderSelector.getCurrentLeader();
@@ -579,10 +572,10 @@ public class DruidCoordinator
   {
     return ImmutableList.of(
         new UpdateCoordinatorStateAndPrepareCluster(),
-        new RunRules(),
+        new RunRules(segmentsMetadataManager::markSegmentsAsUnused),
         new UpdateReplicationStatus(),
         new UnloadUnusedSegments(loadQueueManager),
-        new MarkOvershadowedSegmentsAsUnused(DruidCoordinator.this),
+        new MarkOvershadowedSegmentsAsUnused(segmentsMetadataManager::markSegmentsAsUnused),
         new BalanceSegments(),
         new CollectSegmentAndServerStats(DruidCoordinator.this)
     );

server/src/main/java/org/apache/druid/server/coordinator/duty/CollectSegmentAndServerStats.java

@@ -27,7 +27,6 @@ import org.apache.druid.server.coordinator.DruidCoordinator;
 import org.apache.druid.server.coordinator.DruidCoordinatorRuntimeParams;
 import org.apache.druid.server.coordinator.ServerHolder;
 import org.apache.druid.server.coordinator.loading.LoadQueuePeon;
-import org.apache.druid.server.coordinator.loading.StrategicSegmentAssigner;
 import org.apache.druid.server.coordinator.stats.CoordinatorRunStats;
 import org.apache.druid.server.coordinator.stats.Dimension;
 import org.apache.druid.server.coordinator.stats.RowKey;
@@ -60,9 +59,6 @@ public class CollectSegmentAndServerStats implements CoordinatorDuty
           .forEach(this::logHistoricalTierStats);
     collectSegmentStats(params);
 
-    StrategicSegmentAssigner segmentAssigner = params.getSegmentAssigner();
-    segmentAssigner.makeAlerts();
-
     return params;
   }
 

server/src/main/java/org/apache/druid/server/coordinator/duty/MarkOvershadowedSegmentsAsUnused.java

@@ -24,7 +24,6 @@ import org.apache.druid.client.ImmutableDruidServer;
 import org.apache.druid.java.util.common.DateTimes;
 import org.apache.druid.java.util.common.logger.Logger;
 import org.apache.druid.server.coordinator.DruidCluster;
-import org.apache.druid.server.coordinator.DruidCoordinator;
 import org.apache.druid.server.coordinator.DruidCoordinatorRuntimeParams;
 import org.apache.druid.server.coordinator.ServerHolder;
 import org.apache.druid.server.coordinator.stats.CoordinatorRunStats;
@@ -42,15 +41,21 @@ import java.util.HashSet;
 import java.util.Map;
 import java.util.Set;
 
+/**
+ * Marks segments that are overshadowed by currently served segments as unused.
+ * This duty runs only if the Coordinator has been running long enough to have a
+ * refreshed metadata view. This duration is controlled by the dynamic config
+ * {@code millisToWaitBeforeDeleting}.
+ */
 public class MarkOvershadowedSegmentsAsUnused implements CoordinatorDuty
 {
   private static final Logger log = new Logger(MarkOvershadowedSegmentsAsUnused.class);
 
-  private final DruidCoordinator coordinator;
+  private final SegmentDeleteHandler deleteHandler;
 
-  public MarkOvershadowedSegmentsAsUnused(DruidCoordinator coordinator)
+  public MarkOvershadowedSegmentsAsUnused(SegmentDeleteHandler deleteHandler)
   {
-    this.coordinator = coordinator;
+    this.deleteHandler = deleteHandler;
   }
 
   @Override
@@ -104,7 +109,9 @@ public class MarkOvershadowedSegmentsAsUnused implements CoordinatorDuty
         (datasource, unusedSegments) -> {
           RowKey datasourceKey = RowKey.of(Dimension.DATASOURCE, datasource);
           stats.add(Stats.Segments.OVERSHADOWED, datasourceKey, unusedSegments.size());
-          coordinator.markSegmentsAsUnused(datasource, unusedSegments);
+
+          int updatedCount = deleteHandler.markSegmentsAsUnused(unusedSegments);
+          log.info("Successfully marked [%d] segments of datasource[%s] as unused.", updatedCount, datasource);
         }
     );
 

server/src/main/java/org/apache/druid/server/coordinator/duty/RunRules.java

@@ -19,9 +19,10 @@
 
 package org.apache.druid.server.coordinator.duty;
 
-import com.google.common.collect.Lists;
+import it.unimi.dsi.fastutil.objects.Object2IntOpenHashMap;
 import org.apache.druid.client.ImmutableDruidDataSource;
 import org.apache.druid.java.util.common.DateTimes;
+import org.apache.druid.java.util.common.Stopwatch;
 import org.apache.druid.java.util.emitter.EmittingLogger;
 import org.apache.druid.metadata.MetadataRuleManager;
 import org.apache.druid.server.coordinator.DruidCluster;
@@ -29,8 +30,11 @@ import org.apache.druid.server.coordinator.DruidCoordinatorRuntimeParams;
 import org.apache.druid.server.coordinator.loading.StrategicSegmentAssigner;
 import org.apache.druid.server.coordinator.rules.BroadcastDistributionRule;
 import org.apache.druid.server.coordinator.rules.Rule;
+import org.apache.druid.server.coordinator.stats.CoordinatorRunStats;
+import org.apache.druid.server.coordinator.stats.Dimension;
+import org.apache.druid.server.coordinator.stats.RowKey;
+import org.apache.druid.server.coordinator.stats.Stats;
 import org.apache.druid.timeline.DataSegment;
-import org.apache.druid.timeline.SegmentId;
 import org.joda.time.DateTime;
 
 import java.util.List;
@@ -38,7 +42,9 @@ import java.util.Set;
 import java.util.stream.Collectors;
 
 /**
- * Duty to run retention rules.
+ * Duty to run retention rules for all used non-overshadowed segments.
+ * Overshadowed segments are marked unused by {@link MarkOvershadowedSegmentsAsUnused}
+ * duty and are eventually unloaded from all servers by {@link UnloadUnusedSegments}.
  * <p>
  * The params returned from {@code run()} must have these fields initialized:
  * <ul>
@@ -49,7 +55,13 @@ import java.util.stream.Collectors;
 public class RunRules implements CoordinatorDuty
 {
   private static final EmittingLogger log = new EmittingLogger(RunRules.class);
-  private static final int MAX_MISSING_RULES = 10;
+
+  private final SegmentDeleteHandler deleteHandler;
+
+  public RunRules(SegmentDeleteHandler deleteHandler)
+  {
+    this.deleteHandler = deleteHandler;
+  }
 
   @Override
   public DruidCoordinatorRuntimeParams run(DruidCoordinatorRuntimeParams params)
@@ -60,10 +72,6 @@ public class RunRules implements CoordinatorDuty
       return params;
     }
 
-    // Get used segments which are overshadowed by other used segments. Those would not need to be loaded and
-    // eventually will be unloaded from Historical servers. Segments overshadowed by *served* used segments are marked
-    // as unused in MarkAsUnusedOvershadowedSegments, and then eventually Coordinator sends commands to Historical nodes
-    // to unload such segments in UnloadUnusedSegments.
     final Set<DataSegment> overshadowed = params.getDataSourcesSnapshot().getOvershadowedSegments();
     final Set<DataSegment> usedSegments = params.getUsedSegments();
     log.info(
@@ -74,16 +82,16 @@ public class RunRules implements CoordinatorDuty
     final StrategicSegmentAssigner segmentAssigner = params.getSegmentAssigner();
     final MetadataRuleManager databaseRuleManager = params.getDatabaseRuleManager();
 
-    int missingRules = 0;
     final DateTime now = DateTimes.nowUtc();
-    final List<SegmentId> segmentsWithMissingRules = Lists.newArrayListWithCapacity(MAX_MISSING_RULES);
-
-    // Run through all matched rules for used segments
+    final Object2IntOpenHashMap<String> datasourceToSegmentsWithNoRule = new Object2IntOpenHashMap<>();
     for (DataSegment segment : usedSegments) {
+      // Do not apply rules on overshadowed segments as they will be
+      // marked unused and eventually unloaded from all historicals
       if (overshadowed.contains(segment)) {
-        // Skip overshadowed segments
         continue;
       }
+
+      // Find and apply matching rule
       List<Rule> rules = databaseRuleManager.getRulesWithDefault(segment.getDataSource());
       boolean foundMatchingRule = false;
       for (Rule rule : rules) {
@@ -95,25 +103,59 @@ public class RunRules implements CoordinatorDuty
       }
 
       if (!foundMatchingRule) {
-        if (segmentsWithMissingRules.size() < MAX_MISSING_RULES) {
-          segmentsWithMissingRules.add(segment.getId());
-        }
-        missingRules++;
+        datasourceToSegmentsWithNoRule.addTo(segment.getDataSource(), 1);
       }
     }
 
-    if (!segmentsWithMissingRules.isEmpty()) {
-      log.makeAlert("Unable to find matching rules!")
-         .addData("segmentsWithMissingRulesCount", missingRules)
-         .addData("segmentsWithMissingRules", segmentsWithMissingRules)
-         .emit();
-    }
+    processSegmentDeletes(segmentAssigner, params.getCoordinatorStats());
+    alertForSegmentsWithNoRules(datasourceToSegmentsWithNoRule);
+    alertForInvalidRules(segmentAssigner);
 
     return params.buildFromExisting()
                  .withBroadcastDatasources(getBroadcastDatasources(params))
                  .build();
   }
 
+  private void processSegmentDeletes(
+      StrategicSegmentAssigner segmentAssigner,
+      CoordinatorRunStats runStats
+  )
+  {
+    segmentAssigner.getSegmentsToDelete().forEach((datasource, segmentIds) -> {
+      final Stopwatch stopwatch = Stopwatch.createStarted();
+      int numUpdatedSegments = deleteHandler.markSegmentsAsUnused(segmentIds);
+
+      RowKey rowKey = RowKey.of(Dimension.DATASOURCE, datasource);
+      runStats.add(Stats.Segments.DELETED, rowKey, numUpdatedSegments);
+
+      log.info(
+          "Successfully marked [%d] segments of datasource[%s] as unused in [%d]ms.",
+          numUpdatedSegments, datasource, stopwatch.millisElapsed()
+      );
+    });
+  }
+
+  private void alertForSegmentsWithNoRules(Object2IntOpenHashMap<String> datasourceToSegmentsWithNoRule)
+  {
+    datasourceToSegmentsWithNoRule.object2IntEntrySet().fastForEach(
+        entry -> log.noStackTrace().makeAlert(
+            "No matching retention rule for [%d] segments in datasource[%s]",
+            entry.getIntValue(), entry.getKey()
+        ).emit()
+    );
+  }
+
+  private void alertForInvalidRules(StrategicSegmentAssigner segmentAssigner)
+  {
+    segmentAssigner.getDatasourceToInvalidLoadTiers().forEach(
+        (datasource, invalidTiers) -> log.makeAlert(
+            "Load rules for datasource[%s] refer to invalid tiers[%s]."
+            + " Update the load rules or add servers for these tiers.",
+            datasource, invalidTiers
+        ).emit()
+    );
+  }
+
   private Set<String> getBroadcastDatasources(DruidCoordinatorRuntimeParams params)
   {
     final Set<String> broadcastDatasources =

server/src/main/java/org/apache/druid/server/coordinator/duty/SegmentDeleteHandler.java

@@ -0,0 +1,31 @@
+/*
+ * 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.duty;
+
+import org.apache.druid.timeline.SegmentId;
+
+import java.util.Set;
+
+public interface SegmentDeleteHandler
+{
+
+  int markSegmentsAsUnused(Set<SegmentId> segmentIds);
+
+}

server/src/main/java/org/apache/druid/server/coordinator/loading/StrategicSegmentAssigner.java

@@ -33,7 +33,9 @@ import org.apache.druid.server.coordinator.stats.Dimension;
 import org.apache.druid.server.coordinator.stats.RowKey;
 import org.apache.druid.server.coordinator.stats.Stats;
 import org.apache.druid.timeline.DataSegment;
+import org.apache.druid.timeline.SegmentId;
 
+import javax.annotation.concurrent.NotThreadSafe;
 import java.util.ArrayList;
 import java.util.Comparator;
 import java.util.HashMap;
@@ -51,6 +53,7 @@ import java.util.stream.Collectors;
  * <p>
  * An instance of this class is freshly created for each coordinator run.
  */
+@NotThreadSafe
 public class StrategicSegmentAssigner implements SegmentActionHandler
 {
   private static final EmittingLogger log = new EmittingLogger(StrategicSegmentAssigner.class);
@@ -65,8 +68,9 @@ public class StrategicSegmentAssigner implements SegmentActionHandler
 
   private final boolean useRoundRobinAssignment;
 
-  private final Set<String> tiersWithNoServer = new HashSet<>();
+  private final Map<String, Set<String>> datasourceToInvalidLoadTiers = new HashMap<>();
   private final Map<String, Integer> tierToHistoricalCount = new HashMap<>();
+  private final Map<String, Set<SegmentId>> segmentsToDelete = new HashMap<>();
 
   public StrategicSegmentAssigner(
       SegmentLoadQueueManager loadQueueManager,
@@ -100,11 +104,14 @@ public class StrategicSegmentAssigner implements SegmentActionHandler
     return replicaCountMap.toReplicationStatus();
   }
 
-  public void makeAlerts()
+  public Map<String, Set<SegmentId>> getSegmentsToDelete()
   {
-    if (!tiersWithNoServer.isEmpty()) {
-      log.makeAlert("Tiers [%s] have no servers! Check your cluster configuration.", tiersWithNoServer).emit();
-    }
+    return segmentsToDelete;
+  }
+
+  public Map<String, Set<String>> getDatasourceToInvalidLoadTiers()
+  {
+    return datasourceToInvalidLoadTiers;
   }
 
   /**
@@ -197,7 +204,7 @@ public class StrategicSegmentAssigner implements SegmentActionHandler
   {
     final Set<String> allTiersInCluster = Sets.newHashSet(cluster.getTierNames());
 
-    if (tierToReplicaCount == null || tierToReplicaCount.isEmpty()) {
+    if (tierToReplicaCount.isEmpty()) {
       // Track the counts for a segment even if it requires 0 replicas on all tiers
       replicaCountMap.computeIfAbsent(segment.getId(), DruidServer.DEFAULT_TIER);
     } else {
@@ -209,7 +216,8 @@ public class StrategicSegmentAssigner implements SegmentActionHandler
         replicaCount.setRequired(requiredReplicas, tierToHistoricalCount.getOrDefault(tier, 0));
 
         if (!allTiersInCluster.contains(tier)) {
-          tiersWithNoServer.add(tier);
+          datasourceToInvalidLoadTiers.computeIfAbsent(segment.getDataSource(), ds -> new HashSet<>())
+                                      .add(tier);
         }
       });
     }
@@ -349,9 +357,9 @@ public class StrategicSegmentAssigner implements SegmentActionHandler
   @Override
   public void deleteSegment(DataSegment segment)
   {
-    loadQueueManager.deleteSegment(segment);
-    RowKey rowKey = RowKey.of(Dimension.DATASOURCE, segment.getDataSource());
-    stats.add(Stats.Segments.DELETED, rowKey, 1);
+    segmentsToDelete
+        .computeIfAbsent(segment.getDataSource(), ds -> new HashSet<>())
+        .add(segment.getId());
   }
 
   /**

server/src/test/java/org/apache/druid/server/coordinator/BalanceSegmentsProfiler.java

@@ -46,6 +46,7 @@ import java.util.ArrayList;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.List;
+import java.util.Set;
 
 /**
  * TODO convert benchmarks to JMH
@@ -143,7 +144,7 @@ public class BalanceSegmentsProfiler
         .build();
 
     BalanceSegments tester = new BalanceSegments();
-    RunRules runner = new RunRules();
+    RunRules runner = new RunRules(Set::size);
     watch.start();
     DruidCoordinatorRuntimeParams balanceParams = tester.run(params);
     DruidCoordinatorRuntimeParams assignParams = runner.run(params);

server/src/test/java/org/apache/druid/server/coordinator/duty/MarkOvershadowedSegmentsAsUnusedTest.java

@@ -19,40 +19,41 @@
 
 package org.apache.druid.server.coordinator.duty;
 
-import com.google.common.collect.ImmutableList;
-import com.google.common.collect.ImmutableSet;
+import com.google.common.collect.Sets;
 import junitparams.JUnitParamsRunner;
 import junitparams.Parameters;
 import org.apache.druid.client.DruidServer;
-import org.apache.druid.client.ImmutableDruidDataSource;
 import org.apache.druid.client.ImmutableDruidServer;
 import org.apache.druid.java.util.common.DateTimes;
 import org.apache.druid.server.coordination.ServerType;
 import org.apache.druid.server.coordinator.CoordinatorDynamicConfig;
 import org.apache.druid.server.coordinator.DruidCluster;
-import org.apache.druid.server.coordinator.DruidCoordinator;
 import org.apache.druid.server.coordinator.DruidCoordinatorRuntimeParams;
 import org.apache.druid.server.coordinator.ServerHolder;
-import org.apache.druid.server.coordinator.loading.LoadQueuePeon;
+import org.apache.druid.server.coordinator.balancer.RandomBalancerStrategy;
+import org.apache.druid.server.coordinator.loading.SegmentLoadQueueManager;
+import org.apache.druid.server.coordinator.loading.TestLoadQueuePeon;
+import org.apache.druid.server.coordinator.simulate.TestSegmentsMetadataManager;
+import org.apache.druid.server.coordinator.stats.CoordinatorRunStats;
+import org.apache.druid.server.coordinator.stats.Dimension;
+import org.apache.druid.server.coordinator.stats.RowKey;
+import org.apache.druid.server.coordinator.stats.Stats;
 import org.apache.druid.timeline.DataSegment;
-import org.easymock.EasyMock;
+import org.apache.druid.timeline.SegmentTimeline;
 import org.joda.time.DateTime;
 import org.joda.time.Interval;
+import org.junit.Assert;
+import org.junit.Before;
 import org.junit.Test;
 import org.junit.runner.RunWith;
 
-import java.util.Collections;
-import java.util.List;
+import java.util.Set;
 
 @RunWith(JUnitParamsRunner.class)
 public class MarkOvershadowedSegmentsAsUnusedTest
 {
-  private final DruidCoordinator coordinator = EasyMock.createStrictMock(DruidCoordinator.class);
-
   private final DateTime start = DateTimes.of("2012-01-01");
 
-  private final LoadQueuePeon mockPeon = EasyMock.createMock(LoadQueuePeon.class);
-  private final ImmutableDruidDataSource druidDataSource = EasyMock.createMock(ImmutableDruidDataSource.class);
   private final DataSegment segmentV0 = DataSegment.builder().dataSource("test")
                                                    .interval(new Interval(start, start.plusHours(1)))
                                                    .version("0")
@@ -61,44 +62,65 @@ public class MarkOvershadowedSegmentsAsUnusedTest
   private final DataSegment segmentV1 = segmentV0.withVersion("1");
   private final DataSegment segmentV2 = segmentV0.withVersion("2");
 
+  private TestSegmentsMetadataManager segmentsMetadataManager;
+
+  @Before
+  public void setup()
+  {
+    segmentsMetadataManager = new TestSegmentsMetadataManager();
+  }
+
   @Test
   @Parameters({"historical", "broker"})
-  public void testRun(String serverTypeString)
+  public void testRun(String serverType)
   {
-    ServerType serverType = ServerType.fromString(serverTypeString);
+    segmentsMetadataManager.addSegment(segmentV0);
+    segmentsMetadataManager.addSegment(segmentV1);
+    segmentsMetadataManager.addSegment(segmentV2);
 
-    MarkOvershadowedSegmentsAsUnused markOvershadowedSegmentsAsUnused =
-        new MarkOvershadowedSegmentsAsUnused(coordinator);
-    final List<DataSegment> usedSegments = ImmutableList.of(segmentV1, segmentV0, segmentV2);
-
-    // Dummy values for comparisons in TreeSet
-    EasyMock.expect(mockPeon.getSegmentsInQueue())
-            .andReturn(Collections.emptySet()).anyTimes();
-    EasyMock.expect(mockPeon.getSegmentsMarkedToDrop())
-            .andReturn(Collections.emptySet()).anyTimes();
-    final ImmutableDruidServer druidServer = new DruidServer("", "", "", 0L, serverType, "", 0)
-        .addDataSegment(segmentV1)
-        .addDataSegment(segmentV2)
-        .toImmutableDruidServer();
-
-    coordinator.markSegmentsAsUnused("test", ImmutableSet.of(segmentV1.getId(), segmentV0.getId()));
-    EasyMock.expectLastCall();
-    EasyMock.replay(mockPeon, coordinator, druidDataSource);
+    final ImmutableDruidServer druidServer =
+        new DruidServer("", "", "", 0L, ServerType.fromString(serverType), "", 0)
+            .addDataSegment(segmentV1)
+            .addDataSegment(segmentV2)
+            .toImmutableDruidServer();
 
     DruidCluster druidCluster = DruidCluster
         .builder()
-        .addTier("normal", new ServerHolder(druidServer, mockPeon))
+        .add(new ServerHolder(druidServer, new TestLoadQueuePeon()))
         .build();
 
     DruidCoordinatorRuntimeParams params = DruidCoordinatorRuntimeParams
         .newBuilder(DateTimes.nowUtc())
-        .withUsedSegmentsInTest(usedSegments)
+        .withSnapshotOfDataSourcesWithAllUsedSegments(
+            segmentsMetadataManager.getSnapshotOfDataSourcesWithAllUsedSegments()
+        )
         .withDruidCluster(druidCluster)
         .withDynamicConfigs(
             CoordinatorDynamicConfig.builder().withMarkSegmentAsUnusedDelayMillis(0).build()
         )
+        .withBalancerStrategy(new RandomBalancerStrategy())
+        .withSegmentAssignerUsing(new SegmentLoadQueueManager(null, null, null))
         .build();
-    markOvershadowedSegmentsAsUnused.run(params);
-    EasyMock.verify(coordinator, druidDataSource);
+
+    SegmentTimeline timeline = segmentsMetadataManager.getSnapshotOfDataSourcesWithAllUsedSegments()
+                                                      .getUsedSegmentsTimelinesPerDataSource()
+                                                      .get("test");
+
+    // Verify that the segments V0 and V1 are overshadowed
+    Assert.assertTrue(timeline.isOvershadowed(segmentV0));
+    Assert.assertTrue(timeline.isOvershadowed(segmentV1));
+
+    // Run the duty and verify that the overshadowed segments are marked unused
+    params = new MarkOvershadowedSegmentsAsUnused(segmentsMetadataManager::markSegmentsAsUnused).run(params);
+
+    Set<DataSegment> updatedUsedSegments = Sets.newHashSet(segmentsMetadataManager.iterateAllUsedSegments());
+    Assert.assertEquals(1, updatedUsedSegments.size());
+    Assert.assertTrue(updatedUsedSegments.contains(segmentV2));
+
+    CoordinatorRunStats runStats = params.getCoordinatorStats();
+    Assert.assertEquals(
+        2L,
+        runStats.get(Stats.Segments.OVERSHADOWED, RowKey.of(Dimension.DATASOURCE, "test"))
+    );
   }
 }

server/src/test/java/org/apache/druid/server/coordinator/duty/RunRulesTest.java

@@ -29,7 +29,6 @@ import org.apache.druid.java.util.common.Intervals;
 import org.apache.druid.java.util.common.concurrent.Execs;
 import org.apache.druid.java.util.common.granularity.Granularities;
 import org.apache.druid.java.util.emitter.EmittingLogger;
-import org.apache.druid.java.util.emitter.core.Event;
 import org.apache.druid.java.util.emitter.core.EventMap;
 import org.apache.druid.java.util.emitter.service.AlertEvent;
 import org.apache.druid.java.util.metrics.StubServiceEmitter;
@@ -69,7 +68,6 @@ import java.util.Collections;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.List;
-import java.util.Map;
 import java.util.Set;
 
 /**
@@ -104,7 +102,7 @@ public class RunRulesTest
     EmittingLogger.registerEmitter(emitter);
     databaseRuleManager = EasyMock.createMock(MetadataRuleManager.class);
     segmentsMetadataManager = EasyMock.createNiceMock(SegmentsMetadataManager.class);
-    ruleRunner = new RunRules();
+    ruleRunner = new RunRules(Set::size);
     loadQueueManager = new SegmentLoadQueueManager(null, segmentsMetadataManager, null);
     balancerExecutor = MoreExecutors.listeningDecorator(Execs.multiThreaded(1, "RunRulesTest-%d"));
   }
@@ -511,20 +509,22 @@ public class RunRulesTest
         .add(createServerHolder("serverNorm", "normal", mockPeon))
         .build();
 
-    DruidCoordinatorRuntimeParams params = createCoordinatorRuntimeParams(druidCluster).build();
+    DruidCoordinatorRuntimeParams params = createCoordinatorRuntimeParams(druidCluster)
+        .withBalancerStrategy(new CostBalancerStrategy(balancerExecutor))
+        .withSegmentAssignerUsing(loadQueueManager)
+        .build();
 
     runDutyAndGetStats(params);
 
-    final List<Event> events = emitter.getEvents();
+    final List<AlertEvent> events = emitter.getAlerts();
     Assert.assertEquals(1, events.size());
 
-    AlertEvent alertEvent = (AlertEvent) events.get(0);
+    AlertEvent alertEvent = events.get(0);
     EventMap eventMap = alertEvent.toMap();
-    Assert.assertEquals("Unable to find matching rules!", eventMap.get("description"));
-
-    Map<String, Object> dataMap = alertEvent.getDataMap();
-    Assert.assertEquals(usedSegments.size(), dataMap.get("segmentsWithMissingRulesCount"));
-
+    Assert.assertEquals(
+        "No matching retention rule for [24] segments in datasource[test]",
+        eventMap.get("description")
+    );
     EasyMock.verify(mockPeon);
   }