Remove unused ThreadPool.Names#SAME

server/src/main/java/org/elasticsearch/threadpool/ThreadPool.java

@@ -27,6 +27,7 @@
 import org.elasticsearch.common.util.concurrent.ThreadContext;
 import org.elasticsearch.core.Nullable;
 import org.elasticsearch.core.TimeValue;
+import org.elasticsearch.core.UpdateForV9;
 import org.elasticsearch.node.Node;
 import org.elasticsearch.node.ReportingService;
 import org.elasticsearch.telemetry.metric.Instrument;
@@ -64,7 +65,6 @@ public class ThreadPool implements ReportingService<ThreadPoolInfo>, Scheduler {
     private static final Logger logger = LogManager.getLogger(ThreadPool.class);
 
     public static class Names {
-        public static final String SAME = "same";
         public static final String GENERIC = "generic";
         public static final String CLUSTER_COORDINATION = "cluster_coordination";
         public static final String GET = "get";
@@ -99,9 +99,13 @@ public static class Names {
     public static final String THREAD_POOL_METRIC_NAME_REJECTED = ".threads.rejected.total";
 
     public enum ThreadPoolType {
+        @Deprecated(forRemoval = true)
+        @UpdateForV9 // no longer used, remove in v9
         DIRECT("direct"),
         FIXED("fixed"),
-        FIXED_AUTO_QUEUE_SIZE("fixed_auto_queue_size"), // TODO: remove in 9.0
+        @Deprecated(forRemoval = true)
+        @UpdateForV9 // no longer used, remove in v9
+        FIXED_AUTO_QUEUE_SIZE("fixed_auto_queue_size"),
         SCALING("scaling");
 
         private final String type;
@@ -127,7 +131,6 @@ public static ThreadPoolType fromType(String type) {
     }
 
     public static final Map<String, ThreadPoolType> THREAD_POOL_TYPES = Map.ofEntries(
-        entry(Names.SAME, ThreadPoolType.DIRECT),
         entry(Names.GENERIC, ThreadPoolType.SCALING),
         entry(Names.GET, ThreadPoolType.FIXED),
         entry(Names.ANALYZE, ThreadPoolType.FIXED),
@@ -335,16 +338,10 @@ public ThreadPool(final Settings settings, MeterRegistry meterRegistry, final Ex
             executors.put(entry.getKey(), executorHolder);
         }
 
-        executors.put(Names.SAME, new ExecutorHolder(EsExecutors.DIRECT_EXECUTOR_SERVICE, new Info(Names.SAME, ThreadPoolType.DIRECT)));
         this.executors = Map.copyOf(executors);
         this.executors.forEach((k, v) -> instruments.put(k, setupMetrics(meterRegistry, k, v)));
         this.instruments = instruments;
-        final List<Info> infos = executors.values()
-            .stream()
-            .filter(holder -> holder.info.getName().equals("same") == false)
-            .map(holder -> holder.info)
-            .toList();
-        this.threadPoolInfo = new ThreadPoolInfo(infos);
+        this.threadPoolInfo = new ThreadPoolInfo(executors.values().stream().map(holder -> holder.info).toList());
         this.scheduler = Scheduler.initScheduler(settings, "scheduler");
         this.slowSchedulerWarnThresholdNanos = SLOW_SCHEDULER_TASK_WARN_THRESHOLD_SETTING.get(settings).nanos();
         this.cachedTimeThread = new CachedTimeThread(
@@ -481,10 +478,6 @@ public ThreadPoolStats stats() {
         List<ThreadPoolStats.Stats> stats = new ArrayList<>();
         for (ExecutorHolder holder : executors.values()) {
             final String name = holder.info.getName();
-            // no need to have info on "same" thread pool
-            if ("same".equals(name)) {
-                continue;
-            }
             int threads = -1;
             int queue = -1;
             int active = -1;

server/src/test/java/org/elasticsearch/threadpool/ESThreadPoolTestCase.java

@@ -20,8 +20,7 @@ protected final ThreadPool.Info info(final ThreadPool threadPool, final String n
                 return info;
             }
         }
-        assert "same".equals(name);
-        return null;
+        return fail(null, "unknown threadpool name: " + name);
     }
 
     protected final ThreadPoolStats.Stats stats(final ThreadPool threadPool, final String name) {
@@ -30,10 +29,10 @@ protected final ThreadPoolStats.Stats stats(final ThreadPool threadPool, final S
                 return stats;
             }
         }
-        throw new IllegalArgumentException(name);
+        return fail(null, "unknown threadpool name: " + name);
     }
 
-    protected final void terminateThreadPoolIfNeeded(final ThreadPool threadPool) throws InterruptedException {
+    protected final void terminateThreadPoolIfNeeded(final ThreadPool threadPool) {
         if (threadPool != null) {
             terminate(threadPool);
         }

server/src/test/java/org/elasticsearch/threadpool/UpdateThreadPoolSettingsTests.java

@@ -29,7 +29,7 @@
 
 public class UpdateThreadPoolSettingsTests extends ESThreadPoolTestCase {
 
-    public void testCorrectThreadPoolTypePermittedInSettings() throws InterruptedException {
+    public void testCorrectThreadPoolTypePermittedInSettings() {
         String threadPoolName = randomThreadPoolName();
         ThreadPool.ThreadPoolType correctThreadPoolType = ThreadPool.THREAD_POOL_TYPES.get(threadPoolName);
         ThreadPool threadPool = null;
@@ -41,13 +41,7 @@ public void testCorrectThreadPoolTypePermittedInSettings() throws InterruptedExc
                     .build(),
                 MeterRegistry.NOOP
             );
-            ThreadPool.Info info = info(threadPool, threadPoolName);
-            if (ThreadPool.Names.SAME.equals(threadPoolName)) {
-                assertNull(info); // we don't report on the "same" thread pool
-            } else {
-                // otherwise check we have the expected type
-                assertEquals(info.getThreadPoolType(), correctThreadPoolType);
-            }
+            assertEquals(info(threadPool, threadPoolName).getThreadPoolType(), correctThreadPoolType);
         } finally {
             terminateThreadPoolIfNeeded(threadPool);
         }

test/framework/src/main/java/org/elasticsearch/common/util/concurrent/DeterministicTaskQueue.java

@@ -379,7 +379,7 @@ public ExecutorService generic() {
 
             @Override
             public ExecutorService executor(String name) {
-                return Names.SAME.equals(name) ? EsExecutors.DIRECT_EXECUTOR_SERVICE : forkingExecutor;
+                return forkingExecutor;
             }
 
             @Override

test/framework/src/test/java/org/elasticsearch/common/util/concurrent/DeterministicTaskQueueTests.java

@@ -443,20 +443,4 @@ public void testThreadPoolSchedulesPeriodicFutureTasks() {
         assertThat(strings, contains("periodic-0", "periodic-1", "periodic-2"));
     }
 
-    public void testSameExecutor() {
-        final DeterministicTaskQueue taskQueue = new DeterministicTaskQueue();
-        final ThreadPool threadPool = taskQueue.getThreadPool();
-        final AtomicBoolean executed = new AtomicBoolean(false);
-        final AtomicBoolean executedNested = new AtomicBoolean(false);
-        threadPool.generic().execute(() -> {
-            final var executor = threadPool.executor(ThreadPool.Names.SAME);
-            assertSame(EsExecutors.DIRECT_EXECUTOR_SERVICE, executor);
-            executor.execute(() -> assertTrue(executedNested.compareAndSet(false, true)));
-            assertThat(executedNested.get(), is(true));
-            assertTrue(executed.compareAndSet(false, true));
-        });
-        taskQueue.runAllRunnableTasks();
-        assertThat(executed.get(), is(true));
-    }
-
 }

x-pack/plugin/ml/qa/native-multi-node-tests/src/javaRestTest/java/org/elasticsearch/xpack/ml/integration/MlDailyMaintenanceServiceIT.java

@@ -9,7 +9,6 @@
 import org.elasticsearch.action.ActionListener;
 import org.elasticsearch.cluster.ClusterName;
 import org.elasticsearch.cluster.service.ClusterService;
-import org.elasticsearch.common.util.concurrent.EsExecutors;
 import org.elasticsearch.core.TimeValue;
 import org.elasticsearch.index.IndexVersion;
 import org.elasticsearch.threadpool.ThreadPool;
@@ -35,7 +34,6 @@
 import static org.hamcrest.Matchers.containsInAnyOrder;
 import static org.hamcrest.Matchers.is;
 import static org.mockito.Mockito.mock;
-import static org.mockito.Mockito.when;
 
 public class MlDailyMaintenanceServiceIT extends MlNativeAutodetectIntegTestCase {
 
@@ -46,7 +44,6 @@ public class MlDailyMaintenanceServiceIT extends MlNativeAutodetectIntegTestCase
     public void setUpMocks() {
         jobConfigProvider = new JobConfigProvider(client(), xContentRegistry());
         threadPool = mock(ThreadPool.class);
-        when(threadPool.executor(ThreadPool.Names.SAME)).thenReturn(EsExecutors.DIRECT_EXECUTOR_SERVICE);
     }
 
     public void testTriggerDeleteJobsInStateDeletingWithoutDeletionTask() throws InterruptedException {

x-pack/plugin/ml/qa/native-multi-node-tests/src/javaRestTest/java/org/elasticsearch/xpack/ml/integration/MlInitializationServiceIT.java

@@ -39,13 +39,11 @@
 
 public class MlInitializationServiceIT extends MlNativeAutodetectIntegTestCase {
 
-    private ThreadPool threadPool;
     private MlInitializationService mlInitializationService;
 
     @Before
     public void setUpMocks() {
-        threadPool = mock(ThreadPool.class);
-        when(threadPool.executor(ThreadPool.Names.SAME)).thenReturn(EsExecutors.DIRECT_EXECUTOR_SERVICE);
+        final var threadPool = mock(ThreadPool.class);
         when(threadPool.executor(MachineLearning.UTILITY_THREAD_POOL_NAME)).thenReturn(EsExecutors.DIRECT_EXECUTOR_SERVICE);
         MlDailyMaintenanceService mlDailyMaintenanceService = mock(MlDailyMaintenanceService.class);
         ClusterService clusterService = mock(ClusterService.class);