Better throttling logging

Author: albertzaharovits

server/src/main/java/org/elasticsearch/index/engine/InternalEngine.java

@@ -2828,12 +2828,24 @@ protected ElasticsearchMergeScheduler createMergeScheduler(ShardId shardId, Inde
         return new ThreadPoolMergeScheduler(shardId, indexSettings, engineConfig.getThreadPool()) {
 
             @Override
-            protected synchronized void activateThrottling(int numActiveMerges) {
+            protected synchronized void activateThrottling(int numRunningMerges, int numQueuedMerges, int configuredMaxMergeCount) {
+                logger.info(
+                    "now throttling indexing: numRunningMerges={}, numQueuedMerges={}, maxNumMergesConfigured={}",
+                    numRunningMerges,
+                    numQueuedMerges,
+                    configuredMaxMergeCount
+                );
                 InternalEngine.this.activateThrottling();
             }
 
             @Override
-            protected synchronized void deactivateThrottling(int numActiveMerges) {
+            protected synchronized void deactivateThrottling(int numRunningMerges, int numQueuedMerges, int configuredMaxMergeCount) {
+                logger.info(
+                    "stop throttling indexing: numRunningMerges={}, numQueuedMerges={}, maxNumMergesConfigured={}",
+                    numRunningMerges,
+                    numQueuedMerges,
+                    configuredMaxMergeCount
+                );
                 InternalEngine.this.deactivateThrottling();
             }
 

server/src/main/java/org/elasticsearch/index/engine/ThreadPoolMergeScheduler.java

@@ -122,13 +122,9 @@ protected void beforeMerge(OnGoingMerge merge) {}
      */
     protected void afterMerge(OnGoingMerge merge) {}
 
-    protected void activateThrottling(int numActiveMerges) {}
+    protected void activateThrottling(int numRunningMerges, int numQueuedMerges, int configuredMaxMergeCount) {}
 
-    protected void deactivateThrottling(int numActiveMerges) {}
-
-    public int getMaxMergeCount() {
-        return config.getMaxMergeCount();
-    }
+    protected void deactivateThrottling(int numRunningMerges, int numQueuedMerges, int configuredMaxMergeCount) {}
 
     @Override
     public MergeScheduler clone() {
@@ -178,18 +174,22 @@ private void maybeExecuteNextMerge() {
     }
 
     private void maybeActivateThrottling() {
+        int numRunningMerges = activeMergeTasksExecutingOnLocalSchedulerList.size();
+        int numQueuedMerges = activeMergeTasksLocalSchedulerQueue.size();
+        int configuredMaxMergeCount = config.getMaxMergeCount();
         // both currently running and enqueued count as "active" for throttling purposes
-        int numActiveMerges = activeMergeTasksExecutingOnLocalSchedulerList.size() + activeMergeTasksLocalSchedulerQueue.size();
-        if (numActiveMerges > config.getMaxMergeCount() && isThrottling.getAndSet(true) == false) {
-            activateThrottling(numActiveMerges);
+        if (numRunningMerges + numQueuedMerges > configuredMaxMergeCount && isThrottling.getAndSet(true) == false) {
+            activateThrottling(numRunningMerges, numQueuedMerges, configuredMaxMergeCount);
         }
     }
 
     private void maybeDeactivateThrottling() {
+        int numRunningMerges = activeMergeTasksExecutingOnLocalSchedulerList.size();
+        int numQueuedMerges = activeMergeTasksLocalSchedulerQueue.size();
+        int configuredMaxMergeCount = config.getMaxMergeCount();
         // both currently running and enqueued count as "active" for throttling purposes
-        int numActiveMerges = activeMergeTasksExecutingOnLocalSchedulerList.size() + activeMergeTasksLocalSchedulerQueue.size();
-        if (numActiveMerges <= config.getMaxMergeCount() && isThrottling.getAndSet(false)) {
-            deactivateThrottling(numActiveMerges);
+        if (numRunningMerges + numQueuedMerges <= configuredMaxMergeCount && isThrottling.getAndSet(false)) {
+            deactivateThrottling(numRunningMerges, numQueuedMerges, configuredMaxMergeCount);
         }
     }