Use search_coordination threadpool in field caps (#79378)

Relates #79212

Author: dnhatn

server/src/main/java/org/elasticsearch/action/fieldcaps/TransportFieldCapabilitiesAction.java

@@ -71,7 +71,7 @@ public TransportFieldCapabilitiesAction(TransportService transportService,
         this.fieldCapabilitiesFetcher = new FieldCapabilitiesFetcher(indicesService);
         final Set<String> metadataFields = indicesService.getAllMetadataFields();
         this.metadataFieldPred = metadataFields::contains;
-        transportService.registerRequestHandler(ACTION_NODE_NAME, ThreadPool.Names.MANAGEMENT,
+        transportService.registerRequestHandler(ACTION_NODE_NAME, ThreadPool.Names.SEARCH_COORDINATION,
             FieldCapabilitiesNodeRequest::new, new NodeTransportHandler());
     }
 
@@ -111,7 +111,7 @@ protected void doExecute(Task task, FieldCapabilitiesRequest request, final Acti
             localIndices,
             nowInMillis,
             concreteIndices,
-            threadPool.executor(ThreadPool.Names.MANAGEMENT),
+            threadPool.executor(ThreadPool.Names.SEARCH_COORDINATION),
             indexResponse -> indexResponses.putIfAbsent(indexResponse.getIndexName(), indexResponse),
             indexFailures::collect,
             countDown
@@ -163,7 +163,7 @@ private Runnable createResponseMerger(FieldCapabilitiesRequest request,
                     if (request.isMergeResults()) {
                         // fork off to the management pool for merging the responses as the operation can run for longer than is acceptable
                         // on a transport thread in case of large numbers of indices and/or fields
-                        threadPool.executor(ThreadPool.Names.MANAGEMENT).submit(
+                        threadPool.executor(ThreadPool.Names.SEARCH_COORDINATION).submit(
                             ActionRunnable.supply(
                                 listener,
                                 () -> merge(indexResponses, request.includeUnmapped(), new ArrayList<>(failures)))

server/src/test/java/org/elasticsearch/action/fieldcaps/RequestDispatcherTests.java

@@ -55,7 +55,6 @@
 import org.elasticsearch.threadpool.TestThreadPool;
 import org.elasticsearch.threadpool.ThreadPool;
 import org.elasticsearch.transport.Transport;
-import org.elasticsearch.transport.TransportException;
 import org.elasticsearch.transport.TransportInterceptor;
 import org.elasticsearch.transport.TransportRequest;
 import org.elasticsearch.transport.TransportRequestOptions;
@@ -133,7 +132,7 @@ public void testHappyCluster() throws Exception {
                 OriginalIndices.NONE,
                 randomNonNegativeLong(),
                 indices.toArray(new String[0]),
-                transportService.threadPool.executor(ThreadPool.Names.MANAGEMENT),
+                transportService.threadPool.executor(ThreadPool.Names.SEARCH_COORDINATION),
                 responseCollector::addIndexResponse,
                 responseCollector::addIndexFailure,
                 responseCollector::onComplete);
@@ -199,7 +198,7 @@ public void testRetryThenOk() throws Exception {
                 OriginalIndices.NONE,
                 randomNonNegativeLong(),
                 indices.toArray(new String[0]),
-                transportService.threadPool.executor(ThreadPool.Names.MANAGEMENT),
+                transportService.threadPool.executor(ThreadPool.Names.SEARCH_COORDINATION),
                 responseCollector::addIndexResponse,
                 responseCollector::addIndexFailure,
                 responseCollector::onComplete
@@ -317,7 +316,7 @@ public void testRetryButFails() throws Exception {
                 OriginalIndices.NONE,
                 randomNonNegativeLong(),
                 indices.toArray(new String[0]),
-                transportService.threadPool.executor(ThreadPool.Names.MANAGEMENT),
+                transportService.threadPool.executor(ThreadPool.Names.SEARCH_COORDINATION),
                 responseCollector::addIndexResponse,
                 responseCollector::addIndexFailure,
                 responseCollector::onComplete);
@@ -435,7 +434,7 @@ public void testSuccessWithAnyMatch() throws Exception {
                 OriginalIndices.NONE,
                 randomNonNegativeLong(),
                 indices.toArray(new String[0]),
-                transportService.threadPool.executor(ThreadPool.Names.MANAGEMENT),
+                transportService.threadPool.executor(ThreadPool.Names.SEARCH_COORDINATION),
                 responseCollector::addIndexResponse,
                 responseCollector::addIndexFailure,
                 responseCollector::onComplete);
@@ -524,7 +523,7 @@ public void testStopAfterAllShardsUnmatched() throws Exception {
                 OriginalIndices.NONE,
                 randomNonNegativeLong(),
                 indices.toArray(new String[0]),
-                transportService.threadPool.executor(ThreadPool.Names.MANAGEMENT),
+                transportService.threadPool.executor(ThreadPool.Names.SEARCH_COORDINATION),
                 responseCollector::addIndexResponse,
                 responseCollector::addIndexFailure,
                 responseCollector::onComplete
@@ -753,7 +752,7 @@ protected void doClose() throws IOException {
 
         @SuppressWarnings("unchecked")
         <T extends TransportResponse> void sendResponse(TransportResponseHandler<T> handler, TransportResponse resp) {
-            threadPool.executor(ThreadPool.Names.MANAGEMENT).submit(new AbstractRunnable() {
+            threadPool.executor(ThreadPool.Names.SEARCH_COORDINATION).submit(new AbstractRunnable() {
                 @Override
                 public void onFailure(Exception e) {
                     throw new AssertionError(e);
@@ -765,20 +764,6 @@ protected void doRun() {
                 }
             });
         }
-
-        <T extends TransportResponse> void sendFailure(TransportResponseHandler<T> handler, Exception e) {
-            threadPool.executor(ThreadPool.Names.MANAGEMENT).submit(new AbstractRunnable() {
-                @Override
-                public void onFailure(Exception e) {
-                    throw new AssertionError(e);
-                }
-
-                @Override
-                protected void doRun() {
-                    handler.handleException(new TransportException(e));
-                }
-            });
-        }
     }
 
     static FieldCapabilitiesRequest randomFieldCapRequest(boolean withFilter) {