[DATAJDBC-488] Resolves an issue with deadlocks in the order of update execution.

spring-data-jdbc/src/test/java/org/springframework/data/jdbc/repository/JdbcRepositoryConcurrencyIntegrationTests.java

@@ -0,0 +1,140 @@
+package org.springframework.data.jdbc.repository;
+
+import junit.framework.AssertionFailedError;
+import lombok.AllArgsConstructor;
+import lombok.Getter;
+import lombok.With;
+import org.junit.ClassRule;
+import org.junit.Rule;
+import org.junit.Test;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.context.annotation.Import;
+import org.springframework.data.annotation.Id;
+import org.springframework.data.jdbc.repository.support.JdbcRepositoryFactory;
+import org.springframework.data.jdbc.testing.TestConfiguration;
+import org.springframework.data.repository.CrudRepository;
+import org.springframework.jdbc.core.namedparam.NamedParameterJdbcTemplate;
+import org.springframework.test.context.ActiveProfiles;
+import org.springframework.test.context.ContextConfiguration;
+import org.springframework.test.context.junit4.rules.SpringClassRule;
+import org.springframework.test.context.junit4.rules.SpringMethodRule;
+import org.springframework.transaction.PlatformTransactionManager;
+import org.springframework.transaction.support.TransactionTemplate;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.concurrent.CountDownLatch;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * @author Myeonghyeon Lee
+ */
+@ContextConfiguration
+@ActiveProfiles("mysql")
+public class JdbcRepositoryConcurrencyIntegrationTests {
+	@Configuration
+	@Import(TestConfiguration.class)
+	static class Config {
+
+		@Autowired JdbcRepositoryFactory factory;
+
+		@Bean
+		Class<?> testClass() {
+			return JdbcRepositoryConcurrencyIntegrationTests.class;
+		}
+
+		@Bean
+		DummyEntityRepository dummyEntityRepository() {
+			return factory.getRepository(DummyEntityRepository.class);
+		}
+	}
+
+	@ClassRule
+	public static final SpringClassRule classRule = new SpringClassRule();
+	@Rule
+	public SpringMethodRule methodRule = new SpringMethodRule();
+
+	@Autowired
+	NamedParameterJdbcTemplate template;
+	@Autowired
+	DummyEntityRepository repository;
+	@Autowired
+	PlatformTransactionManager transactionManager;
+
+	@Test	// DATAJDBC-488
+	public void updateConcurrencyWithEmptyReferences() throws Exception {
+		DummyEntity entity = createDummyEntity();
+		entity = repository.save(entity);
+
+		assertThat(entity.getId()).isNotNull();
+
+		List<DummyEntity> concurrencyEntities = new ArrayList<>();
+		Element element1 = new Element(null, 1L);
+		Element element2 = new Element(null, 2L);
+
+		for (int i = 0; i < 100; i++) {
+			List<Element> newContent = Arrays.asList(
+				element1.withContent(element1.content + i + 2),
+				element2.withContent(element2.content + i + 2)
+			);
+
+			concurrencyEntities.add(entity
+				.withName(entity.getName() + i)
+				.withContent(newContent));
+		}
+
+		TransactionTemplate transactionTemplate = new TransactionTemplate(this.transactionManager);
+
+		List<Exception> exceptions = new CopyOnWriteArrayList<>();
+		CountDownLatch countDownLatch = new CountDownLatch(concurrencyEntities.size());
+		concurrencyEntities.stream()
+			.map(e -> new Thread(() -> {
+				countDownLatch.countDown();
+				try {
+					transactionTemplate.execute(status -> repository.save(e));
+				} catch (Exception ex) {
+					exceptions.add(ex);
+				}
+			}))
+			.forEach(Thread::start);
+
+		countDownLatch.await();
+
+		Thread.sleep(1000);
+		DummyEntity reloaded = repository.findById(entity.id).orElseThrow(AssertionFailedError::new);
+		assertThat(reloaded.content).hasSize(2);
+		assertThat(exceptions).isEmpty();
+	}
+
+	private static DummyEntity createDummyEntity() {
+		return new DummyEntity(null, "Entity Name", new ArrayList<>());
+	}
+
+	interface DummyEntityRepository extends CrudRepository<DummyEntity, Long> {
+	}
+
+	@Getter
+	@AllArgsConstructor
+	static class DummyEntity {
+
+		@Id
+		private Long id;
+		@With
+		String name;
+		@With
+		final List<Element> content;
+
+	}
+
+	@AllArgsConstructor
+	static class Element {
+
+		@Id private Long id;
+		@With final Long content;
+	}
+}

spring-data-jdbc/src/test/resources/org.springframework.data.jdbc.repository/JdbcRepositoryConcurrencyIntegrationTests-mysql.sql

@@ -0,0 +1,2 @@
+CREATE TABLE dummy_entity ( id BIGINT AUTO_INCREMENT PRIMARY KEY, NAME VARCHAR(100));
+CREATE TABLE element (id BIGINT AUTO_INCREMENT PRIMARY KEY, content BIGINT, Dummy_Entity_key BIGINT,dummy_entity BIGINT);

spring-data-relational/src/main/java/org/springframework/data/relational/core/conversion/WritingContext.java

@@ -37,6 +37,7 @@
  * @author Jens Schauder
  * @author Bastian Wilhelm
  * @author Mark Paluch
+ * @author Myeonghyeon Lee
  */
 class WritingContext {
 
@@ -73,14 +74,17 @@ List<DbAction<?>> insert() {
 
 	/**
 	 * Leaves out the isNew check as defined in #DATAJDBC-282
+	 * Possible Deadlocks in Execution Order in #DATAJDBC-488
 	 *
 	 * @return List of {@link DbAction}s
 	 * @see <a href="https://jira.spring.io/browse/DATAJDBC-282">DAJDBC-282</a>
+	 * @see <a href="https://jira.spring.io/browse/DATAJDBC-488">DAJDBC-488</a>
 	 */
 	List<DbAction<?>> update() {
 
-		List<DbAction<?>> actions = new ArrayList<>(deleteReferenced());
+		List<DbAction<?>> actions = new ArrayList<>();
 		actions.add(setRootAction(new DbAction.UpdateRoot<>(entity)));
+		actions.addAll(deleteReferenced());
 		actions.addAll(insertReferenced());
 		return actions;
 	}
@@ -94,8 +98,8 @@ List<DbAction<?>> save() {
 			actions.addAll(insertReferenced());
 		} else {
 
-			actions.addAll(deleteReferenced());
 			actions.add(setRootAction(new DbAction.UpdateRoot<>(entity)));
+			actions.addAll(deleteReferenced());
 			actions.addAll(insertReferenced());
 		}
 

spring-data-relational/src/test/java/org/springframework/data/relational/core/conversion/RelationalEntityUpdateWriterUnitTests.java

@@ -30,6 +30,7 @@
  * Unit tests for the {@link RelationalEntityUpdateWriter}
  *
  * @author Thomas Lang
+ * @author Myeonghyeon Lee
  */
 @RunWith(MockitoJUnitRunner.class)
 public class RelationalEntityUpdateWriterUnitTests {
@@ -51,8 +52,8 @@ public void existingEntityGetsConvertedToDeletePlusUpdate() {
 				.extracting(DbAction::getClass, DbAction::getEntityType, DbActionTestSupport::extractPath, DbActionTestSupport::actualEntityType,
 						DbActionTestSupport::isWithDependsOn) //
 				.containsExactly( //
-						tuple(DbAction.Delete.class, Element.class, "other", null, false), //
-						tuple(DbAction.UpdateRoot.class, SingleReferenceEntity.class, "", SingleReferenceEntity.class, false) //
+						tuple(DbAction.UpdateRoot.class, SingleReferenceEntity.class, "", SingleReferenceEntity.class, false), //
+						tuple(DbAction.Delete.class, Element.class, "other", null, false)	//
 				);
 	}
 

spring-data-relational/src/test/java/org/springframework/data/relational/core/conversion/RelationalEntityWriterUnitTests.java

@@ -49,6 +49,7 @@
  * @author Jens Schauder
  * @author Bastian Wilhelm
  * @author Mark Paluch
+ * @author Myeonghyeon Lee
  */
 @RunWith(MockitoJUnitRunner.class)
 public class RelationalEntityWriterUnitTests {
@@ -156,9 +157,9 @@ public void existingEntityGetsConvertedToDeletePlusUpdate() {
 						DbActionTestSupport::extractPath, //
 						DbActionTestSupport::actualEntityType, //
 						DbActionTestSupport::isWithDependsOn) //
-				.containsExactly( //
-						tuple(Delete.class, Element.class, "other", null, false), //
-						tuple(UpdateRoot.class, SingleReferenceEntity.class, "", SingleReferenceEntity.class, false) //
+				.containsExactly(
+						tuple(UpdateRoot.class, SingleReferenceEntity.class, "", SingleReferenceEntity.class, false), //
+						tuple(Delete.class, Element.class, "other", null, false)	//
 				);
 	}
 
@@ -180,8 +181,8 @@ public void newReferenceTriggersDeletePlusInsert() {
 						DbActionTestSupport::actualEntityType, //
 						DbActionTestSupport::isWithDependsOn) //
 				.containsExactly( //
-						tuple(Delete.class, Element.class, "other", null, false), //
 						tuple(UpdateRoot.class, SingleReferenceEntity.class, "", SingleReferenceEntity.class, false), //
+						tuple(Delete.class, Element.class, "other", null, false), //
 						tuple(Insert.class, Element.class, "other", Element.class, true) //
 				);
 	}
@@ -291,9 +292,9 @@ public void cascadingReferencesTriggerCascadingActionsForUpdate() {
 				DbActionTestSupport::actualEntityType, //
 				DbActionTestSupport::isWithDependsOn) //
 				.containsExactly( //
+						tuple(UpdateRoot.class, CascadingReferenceEntity.class, "", CascadingReferenceEntity.class, false), //
 						tuple(Delete.class, Element.class, "other.element", null, false),
 						tuple(Delete.class, CascadingReferenceMiddleElement.class, "other", null, false),
-						tuple(UpdateRoot.class, CascadingReferenceEntity.class, "", CascadingReferenceEntity.class, false), //
 						tuple(Insert.class, CascadingReferenceMiddleElement.class, "other", CascadingReferenceMiddleElement.class,
 								true), //
 						tuple(Insert.class, CascadingReferenceMiddleElement.class, "other", CascadingReferenceMiddleElement.class,
@@ -447,8 +448,8 @@ public void mapTriggersDeletePlusInsert() {
 						this::getMapKey, //
 						DbActionTestSupport::extractPath) //
 				.containsExactly( //
-						tuple(Delete.class, Element.class, null, "elements"), //
 						tuple(UpdateRoot.class, MapContainer.class, null, ""), //
+						tuple(Delete.class, Element.class, null, "elements"), //
 						tuple(Insert.class, Element.class, "one", "elements") //
 				);
 	}
@@ -469,8 +470,8 @@ public void listTriggersDeletePlusInsert() {
 						this::getListKey, //
 						DbActionTestSupport::extractPath) //
 				.containsExactly( //
-						tuple(Delete.class, Element.class, null, "elements"), //
 						tuple(UpdateRoot.class, ListContainer.class, null, ""), //
+						tuple(Delete.class, Element.class, null, "elements"), //
 						tuple(Insert.class, Element.class, 0, "elements") //
 				);
 	}
@@ -494,9 +495,9 @@ public void multiLevelQualifiedReferencesWithId() {
 						a -> getQualifier(a, listMapContainerElements), //
 						DbActionTestSupport::extractPath) //
 				.containsExactly( //
+						tuple(UpdateRoot.class, ListMapContainer.class, null, null, ""), //
 						tuple(Delete.class, Element.class, null, null, "maps.elements"), //
 						tuple(Delete.class, MapContainer.class, null, null, "maps"), //
-						tuple(UpdateRoot.class, ListMapContainer.class, null, null, ""), //
 						tuple(Insert.class, MapContainer.class, 0, null, "maps"), //
 						tuple(Insert.class, Element.class, null, "one", "maps.elements") //
 				);
@@ -521,9 +522,9 @@ public void multiLevelQualifiedReferencesWithOutId() {
 						a -> getQualifier(a, noIdListMapContainerElements), //
 						DbActionTestSupport::extractPath) //
 				.containsExactly( //
+						tuple(UpdateRoot.class, NoIdListMapContainer.class, null, null, ""), //
 						tuple(Delete.class, NoIdElement.class, null, null, "maps.elements"), //
 						tuple(Delete.class, NoIdMapContainer.class, null, null, "maps"), //
-						tuple(UpdateRoot.class, NoIdListMapContainer.class, null, null, ""), //
 						tuple(Insert.class, NoIdMapContainer.class, 0, null, "maps"), //
 						tuple(Insert.class, NoIdElement.class, 0, "one", "maps.elements") //
 				);