diff --git a/server/src/main/java/org/elasticsearch/index/engine/Engine.java b/server/src/main/java/org/elasticsearch/index/engine/Engine.java
index c9f9ecbe25e..4d5757db52b 100644
--- a/server/src/main/java/org/elasticsearch/index/engine/Engine.java
+++ b/server/src/main/java/org/elasticsearch/index/engine/Engine.java
@@ -283,6 +283,13 @@ public abstract class Engine implements Closeable {
         boolean isThrottled() {
             return lock != NOOP_LOCK;
         }
+
+        boolean throttleLockIsHeldByCurrentThread() { // to be used in assertions and tests only
+            if(isThrottled()) {
+                return lock.isHeldByCurrentThread();
+            }
+            return false;
+        }
     }
 
     /**
diff --git a/server/src/main/java/org/elasticsearch/index/engine/InternalEngine.java b/server/src/main/java/org/elasticsearch/index/engine/InternalEngine.java
index a2d27e14983..3e2c3944245 100644
--- a/server/src/main/java/org/elasticsearch/index/engine/InternalEngine.java
+++ b/server/src/main/java/org/elasticsearch/index/engine/InternalEngine.java
@@ -880,7 +880,7 @@ public class InternalEngine extends Engine {
             ensureOpen();
             assert assertIncomingSequenceNumber(index.origin(), index.seqNo());
             try (Releasable ignored = versionMap.acquireLock(index.uid().bytes());
-                 Releasable indexThrottle = doThrottle ? () -> {} : throttle.acquireThrottle()) {
+                Releasable indexThrottle = doThrottle ? throttle.acquireThrottle() : () -> {}) {
                 lastWriteNanos = index.startTime();
                 /* A NOTE ABOUT APPEND ONLY OPTIMIZATIONS:
                  * if we have an autoGeneratedID that comes into the engine we can potentially optimize
@@ -2308,6 +2308,10 @@ public class InternalEngine extends Engine {
         return throttle.isThrottled();
     }
 
+    boolean throttleLockIsHeldByCurrentThread() {  // to be used in assertions and tests only
+        return throttle.throttleLockIsHeldByCurrentThread();
+    }
+
     @Override
     public long getIndexThrottleTimeInMillis() {
         return throttle.getThrottleTimeInMillis();
diff --git a/server/src/test/java/org/elasticsearch/index/engine/InternalEngineTests.java b/server/src/test/java/org/elasticsearch/index/engine/InternalEngineTests.java
index a2483f13857..169ec24caf8 100644
--- a/server/src/test/java/org/elasticsearch/index/engine/InternalEngineTests.java
+++ b/server/src/test/java/org/elasticsearch/index/engine/InternalEngineTests.java
@@ -210,7 +210,10 @@ import static org.hamcrest.Matchers.lessThanOrEqualTo;
 import static org.hamcrest.Matchers.not;
 import static org.hamcrest.Matchers.notNullValue;
 import static org.hamcrest.Matchers.nullValue;
+import static org.mockito.Mockito.atLeastOnce;
+import static org.mockito.Mockito.doAnswer;
 import static org.mockito.Mockito.spy;
+import static org.mockito.Mockito.verify;
 import static org.mockito.Mockito.when;
 
 public class InternalEngineTests extends EngineTestCase {
@@ -6153,6 +6156,33 @@ public class InternalEngineTests extends EngineTestCase {
         }
     }
 
+    public void testIndexThrottling() throws Exception {
+        final Engine.Index indexWithThrottlingCheck = spy(indexForDoc(createParsedDoc("1", null)));
+        final Engine.Index indexWithoutThrottlingCheck = spy(indexForDoc(createParsedDoc("2", null)));
+        doAnswer(invocation -> {
+            try {
+                assertTrue(engine.throttleLockIsHeldByCurrentThread());
+                return invocation.callRealMethod();
+            } catch (InterruptedException ex) {
+                throw new RuntimeException(ex);
+            }
+        }).when(indexWithThrottlingCheck).startTime();
+        doAnswer(invocation -> {
+            try {
+                assertFalse(engine.throttleLockIsHeldByCurrentThread());
+                return invocation.callRealMethod();
+            } catch (InterruptedException ex) {
+                throw new RuntimeException(ex);
+            }
+        }).when(indexWithoutThrottlingCheck).startTime();
+        engine.activateThrottling();
+        engine.index(indexWithThrottlingCheck);
+        engine.deactivateThrottling();
+        engine.index(indexWithoutThrottlingCheck);
+        verify(indexWithThrottlingCheck, atLeastOnce()).startTime();
+        verify(indexWithoutThrottlingCheck, atLeastOnce()).startTime();
+    }
+
     public void testRealtimeGetOnlyRefreshIfNeeded() throws Exception {
         final AtomicInteger refreshCount = new AtomicInteger();
         final ReferenceManager.RefreshListener refreshListener = new ReferenceManager.RefreshListener() {