SOLR-11748: Remove Autoscaling action throttle

solr/CHANGES.txt

@@ -49,6 +49,14 @@ Apache UIMA 2.3.1
 Apache ZooKeeper 3.4.10
 Jetty 9.3.20.v20170531
 
+Upgrade Notes
+----------------------
+
+* SOLR-11748: The throttling mechanism used to limit the rate of autoscaling events processed
+  has been removed. This deprecates the 'actionThrottlePeriodSeconds' setting in the set-properties
+  Autoscaling API which is now a no-op. Use the 'triggerCooldownPeriodSeconds' instead to pause event
+  processing.
+
 New Features
 ----------------------
 * SOLR-11285: Simulation framework for autoscaling. (ab)
@@ -95,6 +103,8 @@ Other Changes
 
 * SOLR-7733: remove "optimize" from the UI. (Erick Erickson)
 
+* SOLR-11748: Remove Autoscaling action throttle. (shalin)
+
 ==================  7.2.0 ==================
 
 Consult the LUCENE_CHANGES.txt file for additional, low level, changes in this release.

solr/core/src/java/org/apache/solr/cloud/autoscaling/ScheduledTriggers.java

@@ -39,11 +39,9 @@ import java.util.concurrent.TimeUnit;
 import java.util.concurrent.TimeoutException;
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.concurrent.atomic.AtomicLong;
-import java.util.concurrent.atomic.AtomicReference;
 import java.util.concurrent.locks.ReentrantLock;
 import java.util.stream.Collectors;
 
-import com.google.common.annotations.VisibleForTesting;
 import org.apache.commons.lang3.exception.ExceptionUtils;
 import org.apache.lucene.store.AlreadyClosedException;
 import org.apache.solr.client.solrj.cloud.autoscaling.AutoScalingConfig;
@@ -53,7 +51,6 @@ import org.apache.solr.client.solrj.cloud.autoscaling.TriggerEventProcessorStage
 import org.apache.solr.client.solrj.cloud.autoscaling.VersionedData;
 import org.apache.solr.client.solrj.request.CollectionAdminRequest.RequestStatusResponse;
 import org.apache.solr.client.solrj.response.RequestStatusState;
-import org.apache.solr.cloud.ActionThrottle;
 import org.apache.solr.cloud.Stats;
 import org.apache.solr.common.SolrException;
 import org.apache.solr.common.cloud.ZkStateReader;
@@ -116,8 +113,6 @@ public class ScheduledTriggers implements Closeable {
 
   private final AtomicLong triggerDelay = new AtomicLong(DEFAULT_SCHEDULED_TRIGGER_DELAY_SECONDS);
 
-  private final AtomicReference<ActionThrottle> actionThrottle;
-
   private final SolrCloudManager cloudManager;
 
   private final DistribStateManager stateManager;
@@ -136,7 +131,6 @@ public class ScheduledTriggers implements Closeable {
     scheduledThreadPoolExecutor.setRemoveOnCancelPolicy(true);
     scheduledThreadPoolExecutor.setExecuteExistingDelayedTasksAfterShutdownPolicy(false);
     actionExecutor = ExecutorUtil.newMDCAwareSingleThreadExecutor(new DefaultSolrThreadFactory("AutoscalingActionExecutor"));
-    actionThrottle = new AtomicReference<>(new ActionThrottle("action", TimeUnit.SECONDS.toMillis(DEFAULT_ACTION_THROTTLE_PERIOD_SECONDS), cloudManager.getTimeSource()));
     this.cloudManager = cloudManager;
     this.stateManager = cloudManager.getDistribStateManager();
     this.loader = loader;
@@ -183,37 +177,17 @@ public class ScheduledTriggers implements Closeable {
           case TRIGGER_CORE_POOL_SIZE:
             this.scheduledThreadPoolExecutor.setCorePoolSize(((Number) newProps.get(key)).intValue());
             break;
-          case ACTION_THROTTLE_PERIOD_SECONDS:
-            long minMsBetweenActions = TimeUnit.SECONDS.toMillis(((Number) newProps.get(key)).longValue());
-            ActionThrottle oldThrottle = this.actionThrottle.get();
-            ActionThrottle newThrottle = null;
-            if (oldThrottle.getLastActionStartedAt() != null) {
-              newThrottle = new ActionThrottle("action",
-                  minMsBetweenActions,
-                  oldThrottle.getLastActionStartedAt(),
-                  cloudManager.getTimeSource());
-            } else  {
-              newThrottle = new ActionThrottle("action", minMsBetweenActions, cloudManager.getTimeSource());
-            }
-            this.actionThrottle.set(newThrottle);
-            break;
         }
       }
     }
     this.autoScalingConfig = autoScalingConfig;
 
-    // reset cooldown and actionThrottle
+    // reset cooldown
     cooldownStart.set(cloudManager.getTimeSource().getTime() - cooldownPeriod.get());
-    actionThrottle.get().reset();
 
     listeners.setAutoScalingConfig(autoScalingConfig);
   }
 
-  @VisibleForTesting
-  void resetActionThrottle() {
-    actionThrottle.get().reset();
-  }
-
   /**
    * Adds a new trigger or replaces an existing one. The replaced trigger, if any, is closed
    * <b>before</b> the new trigger is run. If a trigger is replaced with itself then this
@@ -308,11 +282,6 @@ public class ScheduledTriggers implements Closeable {
             long eventProcessingStart = cloudManager.getTimeSource().getTime();
             log.debug("-- processing actions for " + event);
             try {
-              // let the action executor thread wait instead of the trigger thread so we use the throttle here
-              ActionThrottle actionThrottle = this.actionThrottle.get();
-              actionThrottle.minimumWaitBetweenActions();
-              actionThrottle.markAttemptingAction();
-
               // in future, we could wait for pending tasks in a different thread and re-enqueue
               // this event so that we continue processing other events and not block this action executor
               waitForPendingTasks(newTrigger, actions);

solr/core/src/test/org/apache/solr/cloud/autoscaling/TriggerIntegrationTest.java

@@ -1347,24 +1347,6 @@ public class TriggerIntegrationTest extends SolrCloudTestCase {
       for (int i = 0; i < 8; i++) {
         scheduledTriggers.remove(triggerList.get(i).getName());
       }
-
-      config = config.withProperties(Collections.singletonMap(AutoScalingParams.ACTION_THROTTLE_PERIOD_SECONDS, 6));
-      scheduledTriggers.setAutoScalingConfig(config);
-      lastActionExecutedAt.set(0);
-      throttlingDelayMs.set(TimeUnit.SECONDS.toMillis(6));
-      triggerFiredLatch = new CountDownLatch(2);
-      Map<String, Object> props = map("waitFor", 0L, "actions", Collections.singletonList(map("name","throttler", "class", ThrottlingTesterAction.class.getName())));
-      scheduledTriggers.add(new NodeAddedTrigger("y1", props, resourceLoader, solrCloudManager));
-      scheduledTriggers.add(new NodeAddedTrigger("y2", props, resourceLoader, solrCloudManager));
-      scheduledTriggers.resetActionThrottle();
-      JettySolrRunner newNode = cluster.startJettySolrRunner();
-      assertTrue(getTriggerFiredLatch().await(20, TimeUnit.SECONDS));
-      for (int i = 0; i < cluster.getJettySolrRunners().size(); i++) {
-        if (cluster.getJettySolrRunner(i) == newNode) {
-          cluster.stopJettySolrRunner(i);
-          break;
-        }
-      }
     }
   }
 

solr/solr-ref-guide/src/solrcloud-autoscaling-api.adoc

@@ -594,9 +594,6 @@ Solr pauses all other triggers for this cool down period after a trigger fires s
 `triggerCorePoolSize`::
 The core pool size of the `ScheduledThreadPoolExecutor` used to schedule triggers. The default is `4` threads.
 
-`actionThrottlePeriodSeconds`::
-This is the minimum throttling delay between executing actions for triggers. It is guaranteed that actions for two trigger events are executed after this delay period. The default is `5` seconds.
-
 The command allows setting arbitrary properties in addition to the above properties. Such arbitrary properties can be useful in custom `TriggerAction` instances.
 
 .Change default `triggerScheduleDelaySeconds`

solr/solrj/src/java/org/apache/solr/common/params/AutoScalingParams.java

@@ -68,5 +68,7 @@ public interface AutoScalingParams {
   String TRIGGER_SCHEDULE_DELAY_SECONDS = "triggerScheduleDelaySeconds";
   String TRIGGER_COOLDOWN_PERIOD_SECONDS = "triggerCooldownPeriodSeconds";
   String TRIGGER_CORE_POOL_SIZE = "triggerCorePoolSize";
+
+  @Deprecated
   String ACTION_THROTTLE_PERIOD_SECONDS = "actionThrottlePeriodSeconds";
 }