Closes #2599 - add locking to Query to enable adapter clustering

lib/taskana-core-test/pom.xml

@@ -72,6 +72,12 @@
       <version>${version.equalsverifier}</version>
       <scope>test</scope>
     </dependency>
+    <dependency>
+      <groupId>pro.taskana</groupId>
+      <artifactId>taskana-common-test</artifactId>
+      <version>8.0.2-SNAPSHOT</version>
+      <scope>test</scope>
+    </dependency>
   </dependencies>
 
 </project>

lib/taskana-core-test/src/test/java/acceptance/task/query/TaskQueryImplAccTest.java

@@ -7,11 +7,17 @@
 import static pro.taskana.testapi.DefaultTestEntities.defaultTestObjectReference;
 import static pro.taskana.testapi.DefaultTestEntities.defaultTestWorkbasket;
 
+import java.security.PrivilegedAction;
 import java.time.Instant;
+import java.util.ArrayList;
+import java.util.Collections;
 import java.util.List;
 import java.util.Map;
+import java.util.function.Consumer;
 import java.util.function.Function;
+import java.util.stream.Collectors;
 import java.util.stream.Stream;
+import javax.security.auth.Subject;
 import org.assertj.core.api.ThrowableAssert.ThrowingCallable;
 import org.junit.jupiter.api.BeforeAll;
 import org.junit.jupiter.api.DynamicTest;
@@ -26,8 +32,13 @@
 import pro.taskana.common.api.IntInterval;
 import pro.taskana.common.api.KeyDomain;
 import pro.taskana.common.api.TimeInterval;
+import pro.taskana.common.api.exceptions.SystemException;
 import pro.taskana.common.api.security.CurrentUserContext;
+import pro.taskana.common.api.security.UserPrincipal;
+import pro.taskana.common.internal.InternalTaskanaEngine;
+import pro.taskana.common.internal.util.CheckedConsumer;
 import pro.taskana.common.internal.util.Pair;
+import pro.taskana.common.test.util.ParallelThreadHelper;
 import pro.taskana.task.api.CallbackState;
 import pro.taskana.task.api.TaskCustomField;
 import pro.taskana.task.api.TaskCustomIntField;
@@ -54,6 +65,7 @@
 class TaskQueryImplAccTest {
 
   @TaskanaInject TaskService taskService;
+  @TaskanaInject InternalTaskanaEngine internalTaskanaEngine;
   @TaskanaInject WorkbasketService workbasketService;
   @TaskanaInject CurrentUserContext currentUserContext;
   @TaskanaInject ClassificationService classificationService;
@@ -98,6 +110,91 @@ private void persistPermission(WorkbasketSummary workbasketSummary) throws Excep
         .buildAndStore(workbasketService, "businessadmin");
   }
 
+  @Nested
+  @TestInstance(Lifecycle.PER_CLASS)
+  class LockResultsEqualsTest {
+    private static final Integer LOCK_RESULTS_EQUALS = 2;
+    WorkbasketSummary wb1;
+    TaskSummary taskSummary1;
+    TaskSummary taskSummary2;
+    TaskSummary taskSummary3;
+    TaskSummary taskSummary4;
+
+    @WithAccessId(user = "user-1-1")
+    @BeforeAll
+    void setup() throws Exception {
+      wb1 = createWorkbasketWithPermission();
+
+      taskSummary1 = taskInWorkbasket(wb1).state(TaskState.READY)
+          .buildAndStoreAsSummary(taskService);
+      taskSummary2 = taskInWorkbasket(wb1).state(TaskState.READY)
+          .buildAndStoreAsSummary(taskService);
+      taskSummary3 =
+          taskInWorkbasket(wb1).state(TaskState.READY)
+              .buildAndStoreAsSummary(taskService);
+      taskSummary4 = taskInWorkbasket(wb1).state(TaskState.READY)
+          .buildAndStoreAsSummary(taskService);
+
+    }
+
+    @Test
+    void should_ReturnDifferentTasks_For_LockResultsEqualsTwo() throws Exception {
+      if (System.getenv("DB") != null && (System.getenv("DB").equals("POSTGRES")
+          || System.getenv("DB").equals("DB2"))) {
+
+        List<TaskSummary> returnedTasks = Collections.synchronizedList(new ArrayList<>());
+        List<String> accessIds =
+            Collections.synchronizedList(
+                Stream.of("admin", "admin")
+                    .collect(Collectors.toList()));
+
+        ParallelThreadHelper.runInThread(
+            getRunnableTest(returnedTasks, accessIds), accessIds.size());
+
+        assertThat(returnedTasks)
+            .extracting(TaskSummary::getId)
+            .containsExactlyInAnyOrder(
+                taskSummary1.getId(), taskSummary2.getId(), taskSummary3.getId(),
+                taskSummary4.getId());
+      }
+    }
+
+    private Runnable getRunnableTest(List<TaskSummary> listedTasks, List<String> accessIds) {
+      return () -> {
+        Subject subject = new Subject();
+        subject.getPrincipals().add(new UserPrincipal(accessIds.remove(0)));
+
+        Consumer<TaskService> consumer =
+            CheckedConsumer.wrap(
+                taskService -> {
+                  internalTaskanaEngine.executeInDatabaseConnection(() -> {
+                    List<TaskSummary> results = taskService
+                        .createTaskQuery()
+                        .workbasketIdIn(wb1.getId())
+                        .stateIn(TaskState.READY)
+                        .lockResultsEquals(LOCK_RESULTS_EQUALS).list();
+                    listedTasks.addAll(results);
+                    for (TaskSummary task : results) {
+                      try {
+                        taskService.claim(task.getId());
+                      } catch (Exception e) {
+                        throw new SystemException(e.getMessage());
+                      }
+                    }
+                  });
+                });
+
+
+        PrivilegedAction<Void> action =
+            () -> {
+              consumer.accept(taskService);
+              return null;
+            };
+        Subject.doAs(subject, action);
+      };
+    }
+  }
+
   @Nested
   @TestInstance(Lifecycle.PER_CLASS)
   class PermissionsTest {

lib/taskana-core/src/main/java/pro/taskana/task/api/TaskQuery.java

@@ -1905,4 +1905,14 @@ TaskQuery orderByCustomIntAttribute(
    * @return the query
    */
   TaskQuery orderByWorkbasketName(SortDirection sortDirection);
+
+  /**
+   * This method locks the returned rows until the end of the transaction using for update.
+   *
+   * @param lockResults determines the number of returned and locked results;
+   *                    if zero, no results are locked, but the number of returned results is not
+   *                    limited
+   * @return the query
+   */
+  TaskQuery lockResultsEquals(Integer lockResults);
 }

lib/taskana-core/src/main/java/pro/taskana/task/internal/TaskQueryImpl.java

@@ -337,6 +337,7 @@ public class TaskQueryImpl implements TaskQuery {
   private CallbackState[] callbackStateNotIn;
   private WildcardSearchField[] wildcardSearchFieldIn;
   private String wildcardSearchValueLike;
+  private Integer lockResults;
 
   TaskQueryImpl(InternalTaskanaEngine taskanaEngine) {
     this.taskanaEngine = taskanaEngine;
@@ -345,6 +346,7 @@ public class TaskQueryImpl implements TaskQuery {
     this.orderByInner = new ArrayList<>();
     this.filterByAccessIdIn = true;
     this.withoutAttachment = false;
+    this.lockResults = 0;
     this.joinWithUserInfo = taskanaEngine.getEngine().getConfiguration().isAddAdditionalUserInfo();
   }
 
@@ -2116,11 +2118,17 @@ public TaskQuery selectAndClaimEquals(boolean selectAndClaim) {
     return this;
   }
 
+  public TaskQuery lockResultsEquals(Integer lockResults) {
+    this.lockResults = lockResults;
+    return this;
+  }
+
   // optimized query for db2 can't be used for now in case of selectAndClaim because of temporary
   // tables and the "for update" clause clashing in db2
   private String getLinkToMapperScript() {
     if (DB.DB2 == getDB()
         && !selectAndClaim
+        && lockResults == 0
         && taskanaEngine.getEngine().getConfiguration().isUseSpecificDb2Taskquery()) {
       return LINK_TO_MAPPER_DB2;
     } else if (selectAndClaim && DB.ORACLE == getDB()) {
@@ -2810,8 +2818,8 @@ public String toString() {
         + Arrays.toString(wildcardSearchFieldIn)
         + ", wildcardSearchValueLike="
         + wildcardSearchValueLike
-        + ", joinWithUserInfo="
-        + joinWithUserInfo
+        + ", lockResults="
+        + lockResults
         + "]";
   }
 }

lib/taskana-core/src/main/java/pro/taskana/task/internal/TaskQuerySqlProvider.java

@@ -72,9 +72,18 @@ public static String queryTaskSummaries() {
         + "<if test='selectAndClaim == true'> "
         + "FETCH FIRST ROW ONLY FOR UPDATE "
         + "</if>"
-        + "<if test=\"_databaseId == 'db2' and selectAndClaim \">WITH RS USE "
+        + "<if test='lockResults and lockResults != 0'> "
+        + "FETCH FIRST ${lockResults} ROWS ONLY FOR UPDATE "
+        + "<if test=\"_databaseId == 'postgres'\">"
+        + "SKIP LOCKED "
+        + "</if>"
+        + "<if test=\"_databaseId == 'db2'\">"
+        + "SKIP LOCKED DATA "
+        + "</if>"
+        + "</if>"
+        + "<if test=\"_databaseId == 'db2' and (selectAndClaim or lockResults != 0) \">WITH RS USE "
         + "AND KEEP UPDATE LOCKS </if>"
-        + "<if test=\"_databaseId == 'db2' and !selectAndClaim \">WITH UR </if>"
+        + "<if test=\"_databaseId == 'db2' and !selectAndClaim and lockResults==0 \">WITH UR </if>"
         + CLOSING_SCRIPT_TAG;
   }
 
@@ -143,10 +152,7 @@ public static String queryTaskSummariesDb2() {
         + "<if test='!orderByOuter.isEmpty()'>"
         + "ORDER BY <foreach item='item' collection='orderByOuter' separator=',' >${item}</foreach>"
         + "</if> "
-        + "<if test='selectAndClaim == true'>"
-        + "FETCH FIRST ROW ONLY FOR UPDATE WITH RS USE AND KEEP UPDATE LOCKS"
-        + "</if>"
-        + "<if test='selectAndClaim == false'> with UR</if>"
+        + "with UR g"
         + CLOSING_SCRIPT_TAG;
   }