Introduce new multi-threaded stress test for the Id generation based on sequences

Author: Sanne

hibernate-reactive-core/src/test/java/org/hibernate/reactive/MultithreadedIdentityGenerationTest.java

@@ -0,0 +1,295 @@
+/* Hibernate, Relational Persistence for Idiomatic Java
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ * Copyright: Red Hat Inc. and Hibernate Authors
+ */
+package org.hibernate.reactive;
+
+import io.vertx.core.AbstractVerticle;
+import io.vertx.core.DeploymentOptions;
+import io.vertx.core.Promise;
+import io.vertx.core.Vertx;
+import io.vertx.core.VertxOptions;
+import io.vertx.ext.unit.Async;
+import io.vertx.ext.unit.TestContext;
+import io.vertx.ext.unit.junit.VertxUnitRunner;
+import jakarta.persistence.Entity;
+import jakarta.persistence.GeneratedValue;
+import jakarta.persistence.Id;
+
+import org.hibernate.SessionFactory;
+import org.hibernate.boot.registry.StandardServiceRegistry;
+import org.hibernate.boot.registry.StandardServiceRegistryBuilder;
+import org.hibernate.cfg.Configuration;
+import org.hibernate.reactive.id.impl.ReactiveGeneratorWrapper;
+import org.hibernate.reactive.provider.ReactiveServiceRegistryBuilder;
+import org.hibernate.reactive.provider.Settings;
+import org.hibernate.reactive.session.ReactiveConnectionSupplier;
+import org.hibernate.reactive.session.impl.ReactiveSessionFactoryImpl;
+import org.hibernate.reactive.stage.Stage;
+import org.hibernate.reactive.stage.impl.StageSessionImpl;
+import org.hibernate.reactive.util.impl.CompletionStages;
+import org.hibernate.reactive.vertx.VertxInstance;
+
+import org.junit.AfterClass;
+import org.junit.BeforeClass;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+import java.util.ArrayList;
+import java.util.BitSet;
+import java.util.List;
+import java.util.concurrent.CompletionStage;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ConcurrentMap;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.TimeUnit;
+
+/**
+ * This is a multi-threaded stress test, intentionally consuming some time.
+ * The purpose is to verify that the sequence optimizer used by Hibernate Reactive
+ * is indeed able to generate unique IDs backed by the database sequences, while
+ * running multiple operations in different threads and on multiple Vert.x eventloops.
+ * A typical reactive application will not require multiple threads, but we
+ * specifically want to test for the case in which the single ID source is being
+ * shared across multiple threads and eventloops.
+ */
+@RunWith(VertxUnitRunner.class)
+public class MultithreadedIdentityGenerationTest {
+
+	/* The number of threads should be higher than the default size of the connection pool so that
+	 * this test is also effective in detecting problems with resource starvation.
+	 */
+	private static final int N_THREADS = 48;
+	private static final int IDS_GENERATED_PER_THREAD = 10000;
+
+	//Should finish much sooner, but generating this amount of IDs could be slow on some CIs
+	private static final int TIMEOUT_MINUTES = 10;
+
+	private static final boolean LOG_SQL = false;
+	private static final Latch startLatch = new Latch( "start", N_THREADS );
+	private static final Latch endLatch = new Latch( "end", N_THREADS );
+
+	private static Stage.SessionFactory stageSessionFactory;
+	private static Vertx vertx;
+	private static SessionFactory sessionFactory;
+
+	@BeforeClass
+	public static void setupSessionFactory() {
+		final VertxOptions vertxOptions = new VertxOptions();
+		vertxOptions.setEventLoopPoolSize( N_THREADS );
+		//We relax the blocked thread checks as we'll actually use latches to block them
+		//intentionally for the purpose of the test; functionally this isn't required
+		//but it's useful as self-test in the design of this, to ensure that the way
+		//things are setup are indeed being run in multiple, separate threads.
+		vertxOptions.setBlockedThreadCheckInterval( TIMEOUT_MINUTES );
+		vertxOptions.setBlockedThreadCheckIntervalUnit( TimeUnit.MINUTES );
+		vertx = Vertx.vertx( vertxOptions );
+		Configuration configuration = new Configuration();
+		configuration.addAnnotatedClass( EntityWithGeneratedId.class );
+		BaseReactiveTest.setDefaultProperties( configuration );
+		configuration.setProperty( Settings.SHOW_SQL, String.valueOf( LOG_SQL ) );
+		StandardServiceRegistryBuilder builder = new ReactiveServiceRegistryBuilder()
+				.applySettings( configuration.getProperties() )
+				//Inject our custom vert.x instance:
+				.addService( VertxInstance.class, () -> vertx );
+		StandardServiceRegistry registry = builder.build();
+		sessionFactory = configuration.buildSessionFactory( registry );
+		stageSessionFactory = sessionFactory.unwrap( Stage.SessionFactory.class );
+	}
+
+	@AfterClass
+	public static void closeSessionFactory() {
+		stageSessionFactory.close();
+	}
+
+	private ReactiveGeneratorWrapper getIdGenerator() {
+		final ReactiveSessionFactoryImpl hibernateSessionFactory = (ReactiveSessionFactoryImpl) sessionFactory;
+		final ReactiveGeneratorWrapper identifierGenerator = (ReactiveGeneratorWrapper) hibernateSessionFactory.getIdentifierGenerator(
+				"org.hibernate.reactive.MultithreadedIdentityGenerationTest$EntityWithGeneratedId" );
+		return identifierGenerator;
+	}
+
+	@Test(timeout = ( 1000 * 60 * 10 ))//10 minutes timeout
+	public void testIdentityGenerator(TestContext context) {
+		final Async async = context.async();
+		final ReactiveGeneratorWrapper idGenerator = getIdGenerator();
+		context.assertNotNull( idGenerator );
+
+		final DeploymentOptions deploymentOptions = new DeploymentOptions();
+		deploymentOptions.setInstances( N_THREADS );
+
+		ResultsCollector allResults = new ResultsCollector();
+
+		vertx
+				.deployVerticle( () -> new IdGenVerticle( idGenerator, allResults ), deploymentOptions )
+				.onSuccess( res -> {
+					endLatch.waitForEveryone();
+					if ( allResultsAreUnique( allResults ) ) {
+						async.complete();
+					}
+					else {
+						context.fail( "Non unique numbers detected" );
+					}
+				} )
+				.onFailure( context::fail )
+				.eventually( unused -> vertx.close() );
+	}
+
+	private boolean allResultsAreUnique(ResultsCollector allResults) {
+		//Add 50 per thread to the total amount of generated ids to allow for gaps
+		//in the hi/lo partitioning (not likely to be necessary)
+		final int expectedSize = N_THREADS * ( IDS_GENERATED_PER_THREAD + 50 );
+		BitSet resultsSeen = new BitSet( expectedSize );
+		boolean failed = false;
+		for ( List<Long> partialResult : allResults.resultsByThread.values() ) {
+			for ( Long aLong : partialResult ) {
+				final int intValue = aLong.intValue();
+				final boolean existing = resultsSeen.get( intValue );
+				if ( existing ) {
+					System.out.println( "Duplicate ID detected: " + intValue );
+					failed = true;
+				}
+				resultsSeen.set( intValue );
+			}
+		}
+		return !failed;
+	}
+
+	private static class IdGenVerticle extends AbstractVerticle {
+
+		private final ReactiveGeneratorWrapper idGenerator;
+		private final ResultsCollector allResults;
+		private final ArrayList<Long> generatedIds = new ArrayList<>( IDS_GENERATED_PER_THREAD );
+
+		public IdGenVerticle(ReactiveGeneratorWrapper idGenerator, ResultsCollector allResults) {
+			this.idGenerator = idGenerator;
+			this.allResults = allResults;
+		}
+
+		@Override
+		public void start(Promise<Void> startPromise) {
+			try {
+				startLatch.reached();
+				startLatch.waitForEveryone();//Not essential, but to ensure a good level of parallelism
+				final String initialThreadName = Thread.currentThread().getName();
+				stageSessionFactory.withSession(
+							s -> generateMultipleIds( idGenerator, s, generatedIds )
+					)
+					.whenComplete( (o, throwable) -> {
+						endLatch.reached();
+						if ( throwable != null ) {
+							startPromise.fail( throwable );
+						}
+						else {
+							if ( !initialThreadName.equals( Thread.currentThread().getName() ) ) {
+								startPromise.fail( "Thread switch detected!" );
+							}
+							else {
+								allResults.deliverResulst( generatedIds );
+								startPromise.complete();
+							}
+						}
+					} );
+			}
+			catch (RuntimeException e) {
+				startPromise.fail( e );
+			}
+		}
+
+		@Override
+		public void stop() {
+			prettyOut( "Verticle stopped " + super.toString() );
+		}
+	}
+
+	private static class ResultsCollector {
+
+		private final ConcurrentMap<String,List<Long>> resultsByThread = new ConcurrentHashMap<>();
+
+		public void deliverResulst(List<Long> generatedIds) {
+			final String threadName = Thread.currentThread().getName();
+			resultsByThread.put( threadName, generatedIds );
+		}
+	}
+
+	private static CompletionStage<Void> generateMultipleIds(
+			ReactiveGeneratorWrapper idGenerator,
+			Stage.Session s,
+			ArrayList<Long> collector) {
+		return CompletionStages.loop( 0, IDS_GENERATED_PER_THREAD, index -> generateIds( idGenerator, s, collector ) );
+	}
+
+	private static CompletionStage<Void> generateIds(
+			ReactiveGeneratorWrapper idGenerator,
+			Stage.Session s,
+			ArrayList<Long> collector) {
+		final Thread beforeOperationThread = Thread.currentThread();
+		return idGenerator.generate( ( (StageSessionImpl) s )
+											 .unwrap( ReactiveConnectionSupplier.class ), new EntityWithGeneratedId() )
+				.thenAccept( o -> {
+					if ( beforeOperationThread != Thread.currentThread() ) {
+						throw new IllegalStateException( "Detected an unexpected switch of carrier threads!" );
+					}
+					collector.add( (Long) o );
+				} );
+	}
+
+	/**
+	 * Trivial entity using a Sequence for Id generation
+	 */
+	@Entity
+	private static class EntityWithGeneratedId {
+		@Id
+		@GeneratedValue
+		Long id;
+
+		String name;
+
+		public EntityWithGeneratedId() {
+		}
+	}
+
+	/**
+	 * Custom latch which is rather verbose about threads reaching the milestones, to help verifying the design
+	 */
+	private static final class Latch {
+		private final String label;
+		private final CountDownLatch countDownLatch;
+
+		public Latch(String label, int membersCount) {
+			this.label = label;
+			this.countDownLatch = new CountDownLatch( membersCount );
+		}
+
+		public void reached() {
+			final long count = countDownLatch.getCount();
+			countDownLatch.countDown();
+			prettyOut( "Reached latch '" + label + "', current countdown is " + ( count - 1 ) );
+		}
+
+		public void waitForEveryone() {
+			try {
+				countDownLatch.await( TIMEOUT_MINUTES, TimeUnit.MINUTES );
+				prettyOut( "Everyone has now breached '" + label + "'" );
+			}
+			catch ( InterruptedException e ) {
+				e.printStackTrace();
+			}
+		}
+	}
+
+	private static void prettyOut(final String message) {
+		final String threadName = Thread.currentThread().getName();
+		final long l = System.currentTimeMillis();
+		final long seconds = ( l / 1000 ) - initialSecond;
+		//We prefix log messages by seconds since bootstrap; I'm preferring this over millisecond precision
+		//as it's not very relevant to see exactly how long each stage took (it's actually distracting)
+		//but it's more useful to group things coarsely when some lock or timeout introduces a significant
+		//divide between some operations (when a starvation or timeout happens it takes some seconds).
+		System.out.println( seconds + " - " + threadName + ": " + message );
+	}
+
+	private static final long initialSecond = ( System.currentTimeMillis() / 1000 );
+
+}