Fix noop_update_total metric in indexing stats cannot be updated by bulk API

CHANGELOG.md

@@ -194,6 +194,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 - Remove shadowJar from `lang-painless` module publication ([#11369](https://github.com/opensearch-project/OpenSearch/issues/11369))
 - Fix remote shards balancer and remove unused variables ([#11167](https://github.com/opensearch-project/OpenSearch/pull/11167))
 - Fix bug where replication lag grows post primary relocation ([#11238](https://github.com/opensearch-project/OpenSearch/pull/11238))
+- Fix noop_update_total metric in indexing stats cannot be updated by bulk API ([#11485](https://github.com/opensearch-project/OpenSearch/pull/11485))
 - Fix template setting override for replication type ([#11417](https://github.com/opensearch-project/OpenSearch/pull/11417))
 
 ### Security

rest-api-spec/src/main/resources/rest-api-spec/test/indices.stats/50_noop_update.yml

@@ -0,0 +1,55 @@
+---
+setup:
+
+  - do:
+      indices.create:
+          index:  test1
+          wait_for_active_shards: all
+          body:
+              settings:
+                index.number_of_shards: 1
+                index.number_of_replicas: 1
+
+  - do:
+      index:
+          index: test1
+          id:    1
+          body:  { "bar": "bar" }
+
+  - do:
+      indices.refresh: {}
+
+# Related issue: https://github.com/opensearch-project/OpenSearch/issues/9857
+---
+"Test noop_update_total metric can be updated by both update API and bulk API":
+  - skip:
+      version: " - 2.99.99" #TODO: change to 2.11.99 after the PR is backported to 2.x
+      reason: "fixed in 3.0"
+
+  - do:
+      update:
+        index: test1
+        id:    1
+        body:  { "doc": { "bar": "bar" } }
+
+  - do:
+      indices.stats:
+        index: test1
+        metric: indexing
+
+  - match: { indices.test1.primaries.indexing.noop_update_total: 1 }
+  - match: { indices.test1.total.indexing.noop_update_total: 1 }
+
+  - do:
+      bulk:
+        body:  |
+          {"update": {"_id": "1", "_index": "test1"}}
+          {"doc": {"bar": "bar"}}
+
+  - do:
+      indices.stats:
+        index: test1
+        metric: indexing
+
+  - match: { indices.test1.primaries.indexing.noop_update_total: 2 }
+  - match: { indices.test1.total.indexing.noop_update_total: 2 }

server/src/internalClusterTest/java/org/opensearch/action/bulk/BulkWithUpdatesIT.java

@@ -35,6 +35,8 @@
 import org.opensearch.action.DocWriteRequest.OpType;
 import org.opensearch.action.DocWriteResponse;
 import org.opensearch.action.admin.indices.alias.Alias;
+import org.opensearch.action.admin.indices.stats.IndicesStatsRequest;
+import org.opensearch.action.admin.indices.stats.IndicesStatsResponse;
 import org.opensearch.action.delete.DeleteRequest;
 import org.opensearch.action.get.GetResponse;
 import org.opensearch.action.index.IndexRequest;
@@ -738,6 +740,12 @@ public void testNoopUpdate() {
             equalTo(2)
         );
 
+        // test noop_update_total metric in stats changed
+        IndicesStatsRequest indicesStatsRequest = new IndicesStatsRequest().indices(indexName).indexing(true);
+        final IndicesStatsResponse indicesStatsResponse = client().admin().indices().stats(indicesStatsRequest).actionGet();
+        assertThat(indicesStatsResponse.getIndex(indexName).getTotal().indexing.getTotal().getNoopUpdateCount(), equalTo(1L));
+        assertThat(indicesStatsResponse.getIndex(indexName).getPrimaries().indexing.getTotal().getNoopUpdateCount(), equalTo(1L));
+
         final BulkItemResponse notFoundUpdate = bulkResponse.getItems()[1];
         assertNotNull(notFoundUpdate.getFailure());
 

server/src/main/java/org/opensearch/action/bulk/TransportShardBulkAction.java

@@ -593,6 +593,7 @@ static boolean executeBulkItemRequest(
                     context.setRequestToExecute(updateResult.action());
                     break;
                 case NOOP:
+                    context.getPrimary().noopUpdate();
                     context.markOperationAsNoOp(updateResult.action());
                     context.markAsCompleted(context.getExecutionResult());
                     return true;