Delete useless loop in TransportBulkAction$BulkOperation.doRun()

CHANGELOG.md

@@ -60,6 +60,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 - Indexed IP field supports `terms_query` with more than 1025 IP masks [#16391](https://github.com/opensearch-project/OpenSearch/pull/16391)
 - Make entries for dependencies from server/build.gradle to gradle version catalog ([#16707](https://github.com/opensearch-project/OpenSearch/pull/16707))
 - Allow extended plugins to be optional ([#16909](https://github.com/opensearch-project/OpenSearch/pull/16909))
+- Delete useless loop in `TransportBulkAction$BulkOperation.doRun` q([#16950](https://github.com/opensearch-project/OpenSearch/pull/16950))
 
 ### Deprecated
 - Performing update operation with default pipeline or final pipeline is deprecated ([#16712](https://github.com/opensearch-project/OpenSearch/pull/16712))

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

@@ -532,6 +532,8 @@ protected void doRun() {
             }
             final ConcreteIndices concreteIndices = new ConcreteIndices(clusterState, indexNameExpressionResolver);
             Metadata metadata = clusterState.metadata();
+            // go over all the requests and create a ShardId -> Operations mapping
+            Map<ShardId, List<BulkItemRequest>> requestsByShard = new HashMap<>();
             for (int i = 0; i < bulkRequest.requests.size(); i++) {
                 DocWriteRequest<?> docWriteRequest = bulkRequest.requests.get(i);
                 // the request can only be null because we set it to null in the previous step, so it gets ignored
@@ -587,6 +589,12 @@ protected void doRun() {
                         default:
                             throw new AssertionError("request type not supported: [" + docWriteRequest.opType() + "]");
                     }
+
+                    ShardId shardId = clusterService.operationRouting()
+                        .indexShards(clusterState, concreteIndex.getName(), docWriteRequest.id(), docWriteRequest.routing())
+                        .shardId();
+                    List<BulkItemRequest> shardRequests = requestsByShard.computeIfAbsent(shardId, shard -> new ArrayList<>());
+                    shardRequests.add(new BulkItemRequest(i, docWriteRequest));
                 } catch (OpenSearchParseException | IllegalArgumentException | RoutingMissingException e) {
                     BulkItemResponse.Failure failure = new BulkItemResponse.Failure(concreteIndex.getName(), docWriteRequest.id(), e);
                     BulkItemResponse bulkItemResponse = new BulkItemResponse(i, docWriteRequest.opType(), failure);
@@ -596,21 +604,6 @@ protected void doRun() {
                 }
             }
 
-            // first, go over all the requests and create a ShardId -> Operations mapping
-            Map<ShardId, List<BulkItemRequest>> requestsByShard = new HashMap<>();
-            for (int i = 0; i < bulkRequest.requests.size(); i++) {
-                DocWriteRequest<?> request = bulkRequest.requests.get(i);
-                if (request == null) {
-                    continue;
-                }
-                String concreteIndex = concreteIndices.getConcreteIndex(request.index()).getName();
-                ShardId shardId = clusterService.operationRouting()
-                    .indexShards(clusterState, concreteIndex, request.id(), request.routing())
-                    .shardId();
-                List<BulkItemRequest> shardRequests = requestsByShard.computeIfAbsent(shardId, shard -> new ArrayList<>());
-                shardRequests.add(new BulkItemRequest(i, request));
-            }
-
             if (requestsByShard.isEmpty()) {
                 BulkItemResponse[] response = responses.toArray(new BulkItemResponse[responses.length()]);
                 long tookMillis = buildTookInMillis(startTimeNanos);