diff --git a/lib/taskana-core/pom.xml b/lib/taskana-core/pom.xml
index d28c367f8..b74117d62 100644
--- a/lib/taskana-core/pom.xml
+++ b/lib/taskana-core/pom.xml
@@ -1,5 +1,5 @@
-<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+<project xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://maven.apache.org/POM/4.0.0"
+		 xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
 	<modelVersion>4.0.0</modelVersion>
 	<groupId>pro.taskana</groupId>
 	<artifactId>taskana-core</artifactId>
@@ -18,10 +18,10 @@
 
 	<developers>
 		<developer>
-		<name>Holger Hagen</name>
-		<email>holger.hagen@novatec-gmbh.de</email>
-		<organization>NovaTec Consulting GmbH</organization>
-		<organizationUrl>https://www.novatec-gmbh.de</organizationUrl>
+			<name>Holger Hagen</name>
+			<email>holger.hagen@novatec-gmbh.de</email>
+			<organization>NovaTec Consulting GmbH</organization>
+			<organizationUrl>https://www.novatec-gmbh.de</organizationUrl>
 		</developer>
 	</developers>
 
@@ -128,11 +128,11 @@
 			<artifactId>slf4j-api</artifactId>
 			<version>1.7.25</version>
 		</dependency>
-        <dependency> 
-            <groupId>org.json</groupId> 
-            <artifactId>json</artifactId> 
-            <version>20180130</version>
-        </dependency>
+		<dependency>
+			<groupId>org.json</groupId>
+			<artifactId>json</artifactId>
+			<version>20180130</version>
+		</dependency>
 		<!-- test dependencies -->
 		<dependency>
 			<groupId>junit</groupId>
@@ -146,30 +146,36 @@
 			<version>2.8.47</version>
 			<scope>test</scope>
 		</dependency>
-        <dependency>
-            <groupId>org.powermock</groupId>
-            <artifactId>powermock-module-junit4</artifactId>
-            <version>${powermock.version}</version>
-            <scope>test</scope>
-        </dependency>
-        <dependency>
-            <groupId>org.powermock</groupId>
-            <artifactId>powermock-api-mockito2</artifactId>
-            <version>${powermock.version}</version>
-            <scope>test</scope>
-        </dependency>
+		<dependency>
+			<groupId>org.powermock</groupId>
+			<artifactId>powermock-module-junit4</artifactId>
+			<version>${powermock.version}</version>
+			<scope>test</scope>
+		</dependency>
+		<dependency>
+			<groupId>org.powermock</groupId>
+			<artifactId>powermock-api-mockito2</artifactId>
+			<version>${powermock.version}</version>
+			<scope>test</scope>
+		</dependency>
 		<dependency>
 			<groupId>com.h2database</groupId>
 			<artifactId>h2</artifactId>
 			<version>1.4.196</version>
 			<scope>test</scope>
 		</dependency>
-        <dependency>
-            <groupId>com.ibm.db2.jcc</groupId>
-            <artifactId>db2jcc4</artifactId>
-            <version>11.1.1.1</version>
-            <scope>test</scope>
-        </dependency>
+		<dependency>
+			<groupId>org.postgresql</groupId>
+			<artifactId>postgresql</artifactId>
+			<version>42.2.2</version>
+			<scope>test</scope>
+		</dependency>
+		<dependency>
+			<groupId>com.ibm.db2.jcc</groupId>
+			<artifactId>db2jcc4</artifactId>
+			<version>11.1.1.1</version>
+			<scope>test</scope>
+		</dependency>
 		<dependency>
 			<groupId>org.apache.logging.log4j</groupId>
 			<artifactId>log4j-slf4j-impl</artifactId>
@@ -246,15 +252,15 @@
 			</plugin>
 		</plugins>
 	</build>
-  <!-- 
-    this repository is needed to fetch com.ibm.db2.jcc
-  -->   
-  <repositories>
-    <repository>
-      <id>novatec public</id>
-      <name>novatec-repository</name>
-      <url>https://repository.novatec-gmbh.de/content/repositories/novatec/</url>
-    </repository>
-  </repositories>
-	
+	<!--
+	  this repository is needed to fetch com.ibm.db2.jcc
+	-->
+	<repositories>
+		<repository>
+			<id>novatec public</id>
+			<name>novatec-repository</name>
+			<url>https://repository.novatec-gmbh.de/content/repositories/novatec/</url>
+		</repository>
+	</repositories>
+
 </project>
diff --git a/lib/taskana-core/src/main/java/pro/taskana/TaskanaEngine.java b/lib/taskana-core/src/main/java/pro/taskana/TaskanaEngine.java
index e562e4280..d08d2442b 100644
--- a/lib/taskana-core/src/main/java/pro/taskana/TaskanaEngine.java
+++ b/lib/taskana-core/src/main/java/pro/taskana/TaskanaEngine.java
@@ -60,7 +60,7 @@ public interface TaskanaEngine {
      * @param connection
      *            - The java.sql.Connection that is controlled by the client
      */
-    void setConnection(java.sql.Connection connection);
+    void setConnection(java.sql.Connection connection) throws java.sql.SQLException;
 
     /**
      * Closes the client's connection, sets it to null and switches to mode PARTICIPATE. Only applicable in mode
@@ -68,20 +68,6 @@ public interface TaskanaEngine {
      */
     void closeConnection();
 
-    /**
-     * Connection management mode. Controls the connection handling of taskana
-     * <ul>
-     * <li>PARTICIPATE - taskana participates in global transaction. This is the default mode</li>
-     * <li>AUTOCOMMIT - taskana commits each API call separately</li>
-     * <li>EXPLICIT - commit processing is managed explicitly by the client</li>
-     * </ul>
-     */
-    enum ConnectionManagementMode {
-        PARTICIPATE,
-        AUTOCOMMIT,
-        EXPLICIT
-    }
-
     /**
      * check whether the current user is member of one of the roles specified.
      *
@@ -100,4 +86,18 @@ public interface TaskanaEngine {
      *             If the current user is not member of any specified role
      */
     void checkRoleMembership(TaskanaRole... roles) throws NotAuthorizedException;
+
+    /**
+     * Connection management mode. Controls the connection handling of taskana
+     * <ul>
+     * <li>PARTICIPATE - taskana participates in global transaction. This is the default mode</li>
+     * <li>AUTOCOMMIT - taskana commits each API call separately</li>
+     * <li>EXPLICIT - commit processing is managed explicitly by the client</li>
+     * </ul>
+     */
+    enum ConnectionManagementMode {
+        PARTICIPATE,
+        AUTOCOMMIT,
+        EXPLICIT
+    }
 }
diff --git a/lib/taskana-core/src/main/java/pro/taskana/configuration/DbSchemaCreator.java b/lib/taskana-core/src/main/java/pro/taskana/configuration/DbSchemaCreator.java
index 6dd7814c9..dfe039744 100644
--- a/lib/taskana-core/src/main/java/pro/taskana/configuration/DbSchemaCreator.java
+++ b/lib/taskana-core/src/main/java/pro/taskana/configuration/DbSchemaCreator.java
@@ -20,6 +20,7 @@ public class DbSchemaCreator {
     private static final Logger LOGGER = LoggerFactory.getLogger(DbSchemaCreator.class);
     private static final String SQL = "/sql";
     private static final String DB_SCHEMA = SQL + "/taskana-schema.sql";
+    private static final String DB_SCHEMA_POSTGRES = SQL + "/taskana-schema-postgres.sql";
     private static final String DB_SCHEMA_DETECTION = SQL + "/schema-detection.sql";
     private DataSource dataSource;
     private StringWriter outWriter = new StringWriter();
@@ -32,6 +33,10 @@ public class DbSchemaCreator {
         this.dataSource = dataSource;
     }
 
+    private static String selectDbScriptFileName(String dbProductName) {
+        return "PostgreSQL".equals(dbProductName) ? DB_SCHEMA_POSTGRES : DB_SCHEMA;
+    }
+
     /**
      * Run all db scripts.
      *
@@ -48,7 +53,8 @@ public class DbSchemaCreator {
         runner.setErrorLogWriter(errorLogWriter);
         try {
             if (!isSchemaPreexisting(runner)) {
-                runner.runScript(new InputStreamReader(this.getClass().getResourceAsStream(DB_SCHEMA)));
+                runner.runScript(new InputStreamReader(this.getClass()
+                    .getResourceAsStream(selectDbScriptFileName(connection.getMetaData().getDatabaseProductName()))));
             }
         } finally {
             runner.closeConnection();
diff --git a/lib/taskana-core/src/main/java/pro/taskana/impl/ClassificationServiceImpl.java b/lib/taskana-core/src/main/java/pro/taskana/impl/ClassificationServiceImpl.java
index bc2c4774e..c700664b1 100644
--- a/lib/taskana-core/src/main/java/pro/taskana/impl/ClassificationServiceImpl.java
+++ b/lib/taskana-core/src/main/java/pro/taskana/impl/ClassificationServiceImpl.java
@@ -1,5 +1,6 @@
 package pro.taskana.impl;
 
+import java.sql.SQLException;
 import java.sql.SQLIntegrityConstraintViolationException;
 import java.time.Duration;
 import java.time.Instant;
@@ -395,10 +396,8 @@ public class ClassificationServiceImpl implements ClassificationService {
     }
 
     private boolean isReferentialIntegrityConstraintViolation(PersistenceException e) {
-        return ((e.getCause().getClass().getName().equals("org.h2.jdbc.JdbcSQLException")
-            && e.getMessage().contains("23503"))
-            || (e.getCause() instanceof SQLIntegrityConstraintViolationException
-                && e.getMessage().contains("-532")));
+        return e.getCause() instanceof SQLException && ((SQLException) e.getCause()).getSQLState().equals("23503")
+            || e.getCause() instanceof SQLIntegrityConstraintViolationException && e.getMessage().contains("-532");
     }
 
 }
diff --git a/lib/taskana-core/src/main/java/pro/taskana/impl/TaskanaEngineImpl.java b/lib/taskana-core/src/main/java/pro/taskana/impl/TaskanaEngineImpl.java
index 5f279a415..8655c489a 100644
--- a/lib/taskana-core/src/main/java/pro/taskana/impl/TaskanaEngineImpl.java
+++ b/lib/taskana-core/src/main/java/pro/taskana/impl/TaskanaEngineImpl.java
@@ -62,16 +62,56 @@ public class TaskanaEngineImpl implements TaskanaEngine {
     protected ConnectionManagementMode mode = ConnectionManagementMode.PARTICIPATE;
     protected java.sql.Connection connection = null;
 
-    public static TaskanaEngine createTaskanaEngine(TaskanaEngineConfiguration taskanaEngineConfiguration) {
-        return new TaskanaEngineImpl(taskanaEngineConfiguration);
-    }
-
     protected TaskanaEngineImpl(TaskanaEngineConfiguration taskanaEngineConfiguration) {
         this.taskanaEngineConfiguration = taskanaEngineConfiguration;
         createTransactionFactory(taskanaEngineConfiguration.getUseManagedTransactions());
         this.sessionManager = createSqlSessionManager();
     }
 
+    public static TaskanaEngine createTaskanaEngine(TaskanaEngineConfiguration taskanaEngineConfiguration) {
+        return new TaskanaEngineImpl(taskanaEngineConfiguration);
+    }
+
+    /**
+     * With sessionStack, we maintain a Stack of SqlSessionManager objects on a per thread basis. SqlSessionManager is
+     * the MyBatis object that wraps database connections. The purpose of this stack is to keep track of nested calls.
+     * Each external API call is wrapped into taskanaEngineImpl.openConnection(); .....
+     * taskanaEngineImpl.returnConnection(); calls. In order to avoid duplicate opening / closing of connections, we use
+     * the sessionStack in the following way: Each time, an openConnection call is received, we push the current
+     * sessionManager onto the stack. On the first call to openConnection, we call sessionManager.startManagedSession()
+     * to open a database connection. On each call to returnConnection() we pop one instance of sessionManager from the
+     * stack. When the stack becomes empty, we close the database connection by calling sessionManager.close()
+     *
+     * @return Stack of SqlSessionManager
+     */
+    protected static Deque<SqlSessionManager> getSessionStack() {
+        Deque<SqlSessionManager> stack = sessionStack.get();
+        if (stack == null) {
+            stack = new ArrayDeque<>();
+            sessionStack.set(stack);
+        }
+        return stack;
+    }
+
+    protected static SqlSessionManager getSessionFromStack() {
+        Deque<SqlSessionManager> stack = getSessionStack();
+        if (stack.isEmpty()) {
+            return null;
+        }
+        return stack.peek();
+    }
+
+    protected static void pushSessionToStack(SqlSessionManager session) {
+        getSessionStack().push(session);
+    }
+
+    protected static void popSessionFromStack() {
+        Deque<SqlSessionManager> stack = getSessionStack();
+        if (!stack.isEmpty()) {
+            stack.pop();
+        }
+    }
+
     @Override
     public TaskService getTaskService() {
         SqlSession session = this.sessionManager;
@@ -140,17 +180,15 @@ public class TaskanaEngineImpl implements TaskanaEngine {
      *            The connection that passed into TaskanaEngine
      */
     @Override
-    public void setConnection(java.sql.Connection connection) {
+    public void setConnection(java.sql.Connection connection) throws SQLException {
         if (connection != null) {
             this.connection = connection;
+            // disabling auto commit for passed connection in order to gain full control over the connection management
+            connection.setAutoCommit(false);
             mode = ConnectionManagementMode.EXPLICIT;
             sessionManager.startManagedSession(connection);
         } else if (this.connection != null) {
-            this.connection = null;
-            if (sessionManager.isManagedSessionStarted()) {
-                sessionManager.close();
-            }
-            mode = ConnectionManagementMode.PARTICIPATE;
+            closeConnection();
         }
     }
 
@@ -291,6 +329,8 @@ public class TaskanaEngineImpl implements TaskanaEngine {
                 configuration.setDatabaseId("db2");
             } else if (databaseProductName.contains("H2")) {
                 configuration.setDatabaseId("h2");
+            } else if (databaseProductName.equals("PostgreSQL")) {
+                configuration.setDatabaseId("postgres");
             } else {
                 LOGGER.error(
                     "Method createSqlSessionManager() didn't find database with name {}. Throwing UnsupportedDatabaseException",
@@ -335,46 +375,6 @@ public class TaskanaEngineImpl implements TaskanaEngine {
         }
     }
 
-    /**
-     * With sessionStack, we maintain a Stack of SqlSessionManager objects on a per thread basis. SqlSessionManager is
-     * the MyBatis object that wraps database connections. The purpose of this stack is to keep track of nested calls.
-     * Each external API call is wrapped into taskanaEngineImpl.openConnection(); .....
-     * taskanaEngineImpl.returnConnection(); calls. In order to avoid duplicate opening / closing of connections, we use
-     * the sessionStack in the following way: Each time, an openConnection call is received, we push the current
-     * sessionManager onto the stack. On the first call to openConnection, we call sessionManager.startManagedSession()
-     * to open a database connection. On each call to returnConnection() we pop one instance of sessionManager from the
-     * stack. When the stack becomes empty, we close the database connection by calling sessionManager.close()
-     *
-     * @return Stack of SqlSessionManager
-     */
-    protected static Deque<SqlSessionManager> getSessionStack() {
-        Deque<SqlSessionManager> stack = sessionStack.get();
-        if (stack == null) {
-            stack = new ArrayDeque<>();
-            sessionStack.set(stack);
-        }
-        return stack;
-    }
-
-    protected static SqlSessionManager getSessionFromStack() {
-        Deque<SqlSessionManager> stack = getSessionStack();
-        if (stack.isEmpty()) {
-            return null;
-        }
-        return stack.peek();
-    }
-
-    protected static void pushSessionToStack(SqlSessionManager session) {
-        getSessionStack().push(session);
-    }
-
-    protected static void popSessionFromStack() {
-        Deque<SqlSessionManager> stack = getSessionStack();
-        if (!stack.isEmpty()) {
-            stack.pop();
-        }
-    }
-
     /**
      * Returns true if the given domain does exist in the configuration.
      *
diff --git a/lib/taskana-core/src/main/java/pro/taskana/impl/persistence/MapTypeHandler.java b/lib/taskana-core/src/main/java/pro/taskana/impl/persistence/MapTypeHandler.java
index 3c58bdef2..0a8f46dc8 100644
--- a/lib/taskana-core/src/main/java/pro/taskana/impl/persistence/MapTypeHandler.java
+++ b/lib/taskana-core/src/main/java/pro/taskana/impl/persistence/MapTypeHandler.java
@@ -1,7 +1,6 @@
 package pro.taskana.impl.persistence;
 
 import java.sql.CallableStatement;
-import java.sql.Clob;
 import java.sql.PreparedStatement;
 import java.sql.ResultSet;
 import java.sql.SQLException;
@@ -30,9 +29,7 @@ public class MapTypeHandler extends BaseTypeHandler<Map> {
             LOGGER.debug("Input-Map before serializing: ", parameter);
             // Convert Map to JSON string
             JSONObject jsonObj = new JSONObject(parameter);
-            Clob content = ps.getConnection().createClob();
-            content.setString(1, jsonObj.toString());
-            ps.setClob(i, content);
+            ps.setString(i, jsonObj.toString());
         } else {
             ps.setNull(i, Types.BLOB);
         }
@@ -40,36 +37,34 @@ public class MapTypeHandler extends BaseTypeHandler<Map> {
 
     @Override
     public Map getNullableResult(ResultSet rs, String columnName) throws SQLException {
-        Clob fieldValue = rs.getClob(columnName);
+        String fieldValue = rs.getString(columnName);
         if (fieldValue != null) {
-            return convertClobToMap(fieldValue);
+            return convertToMap(fieldValue);
         }
         return null;
     }
 
     @Override
     public Map getNullableResult(ResultSet rs, int columnIndex) throws SQLException {
-        Clob fieldValue = rs.getClob(columnIndex);
+        String fieldValue = rs.getString(columnIndex);
         if (fieldValue != null) {
-            return convertClobToMap(fieldValue);
+            return convertToMap(fieldValue);
         }
         return null;
     }
 
     @Override
     public Map getNullableResult(CallableStatement cs, int columnIndex) throws SQLException {
-        Clob fieldValue = cs.getClob(columnIndex);
+        String fieldValue = cs.getString(columnIndex);
         if (fieldValue != null) {
-            return convertClobToMap(fieldValue);
+            return convertToMap(fieldValue);
         }
         return null;
     }
 
-    private Map convertClobToMap(Clob fieldValue) throws SQLException {
-        String content = fieldValue.getSubString(1L, (int) fieldValue.length());
-        JSONObject jsonObj = new JSONObject(content);
-        Map result = jsonObj.toMap();
-        return result;
+    private Map convertToMap(String fieldValue) throws SQLException {
+        JSONObject jsonObj = new JSONObject(fieldValue);
+        return jsonObj.toMap();
     }
 
 }
diff --git a/lib/taskana-core/src/main/java/pro/taskana/mappings/AttachmentMapper.java b/lib/taskana-core/src/main/java/pro/taskana/mappings/AttachmentMapper.java
index 62f952901..50a614617 100644
--- a/lib/taskana-core/src/main/java/pro/taskana/mappings/AttachmentMapper.java
+++ b/lib/taskana-core/src/main/java/pro/taskana/mappings/AttachmentMapper.java
@@ -11,7 +11,6 @@ import org.apache.ibatis.annotations.Results;
 import org.apache.ibatis.annotations.Select;
 import org.apache.ibatis.annotations.Update;
 import org.apache.ibatis.type.ClobTypeHandler;
-import org.apache.ibatis.type.JdbcType;
 
 import pro.taskana.impl.AttachmentImpl;
 import pro.taskana.impl.AttachmentSummaryImpl;
@@ -46,7 +45,7 @@ public interface AttachmentMapper {
         @Result(property = "objectReference.value", column = "REF_VALUE"),
         @Result(property = "channel", column = "CHANNEL"),
         @Result(property = "received", column = "RECEIVED"),
-        @Result(property = "customAttributes", column = "CUSTOM_ATTRIBUTES", jdbcType = JdbcType.CLOB,
+        @Result(property = "customAttributes", column = "CUSTOM_ATTRIBUTES",
             javaType = Map.class, typeHandler = MapTypeHandler.class)
     })
     List<AttachmentImpl> findAttachmentsByTaskId(@Param("taskId") String taskId);
@@ -70,7 +69,7 @@ public interface AttachmentMapper {
         @Result(property = "objectReference.value", column = "REF_VALUE"),
         @Result(property = "channel", column = "CHANNEL"),
         @Result(property = "received", column = "RECEIVED"),
-        @Result(property = "customAttributes", column = "CUSTOM_ATTRIBUTES", jdbcType = JdbcType.CLOB,
+        @Result(property = "customAttributes", column = "CUSTOM_ATTRIBUTES",
             javaType = Map.class, typeHandler = MapTypeHandler.class)
     })
     AttachmentImpl getAttachment(@Param("attachmentId") String attachmentId);
@@ -107,7 +106,7 @@ public interface AttachmentMapper {
         + "<if test=\"_databaseId == 'db2'\">with UR </if> "
         + "</script>")
     @Results(value = {
-        @Result(property = "customAttributes", column = "CUSTOM_ATTRIBUTES", jdbcType = JdbcType.CLOB,
+        @Result(property = "customAttributes", column = "CUSTOM_ATTRIBUTES",
             javaType = String.class, typeHandler = ClobTypeHandler.class)
     })
     String getCustomAttributesAsString(@Param("attachmentId") String attachmentId);
diff --git a/lib/taskana-core/src/main/java/pro/taskana/mappings/JobMapper.java b/lib/taskana-core/src/main/java/pro/taskana/mappings/JobMapper.java
index 50f41f488..0e323eb24 100644
--- a/lib/taskana-core/src/main/java/pro/taskana/mappings/JobMapper.java
+++ b/lib/taskana-core/src/main/java/pro/taskana/mappings/JobMapper.java
@@ -9,7 +9,6 @@ import org.apache.ibatis.annotations.Result;
 import org.apache.ibatis.annotations.Results;
 import org.apache.ibatis.annotations.Select;
 import org.apache.ibatis.annotations.Update;
-import org.apache.ibatis.type.JdbcType;
 
 import pro.taskana.impl.Job;
 import pro.taskana.impl.persistence.MapTypeHandler;
@@ -19,8 +18,19 @@ import pro.taskana.impl.persistence.MapTypeHandler;
  */
 public interface JobMapper {
 
-    @Insert("INSERT INTO TASKANA.JOB (JOB_ID, CREATED, STARTED, COMPLETED, STATE, EXECUTOR, ARGUMENTS) "
-        + "VALUES (NEXT VALUE FOR TASKANA.JOB_SEQ, #{job.created}, #{job.started}, #{job.completed}, #{job.state}, #{job.executor}, #{job.arguments,jdbcType=CLOB, javaType=java.util.Map,typeHandler=pro.taskana.impl.persistence.MapTypeHandler} )")
+    @Insert("<script>"
+        + "INSERT INTO TASKANA.JOB (JOB_ID, CREATED, STARTED, COMPLETED, STATE, EXECUTOR, ARGUMENTS) "
+        + "VALUES ("
+        + "<choose>"
+        + "<when test=\"_databaseId == 'db2'\">"
+        + "NEXT VALUE FOR TASKANA.JOB_SEQ"
+        + "</when>"
+        + "<otherwise>"
+        + "nextval('TASKANA.JOB_SEQ')"
+        + "</otherwise>"
+        + "</choose>"
+        + ", #{job.created}, #{job.started}, #{job.completed}, #{job.state}, #{job.executor}, #{job.arguments,javaType=java.util.Map,typeHandler=pro.taskana.impl.persistence.MapTypeHandler} )"
+        + "</script>")
     void insertJob(@Param("job") Job job);
 
     @Select("SELECT   JOB_ID, CREATED, STARTED, COMPLETED, STATE, EXECUTOR, ARGUMENTS "
@@ -34,7 +44,7 @@ public interface JobMapper {
         @Result(property = "completed", column = "COMPLETED"),
         @Result(property = "state", column = "STATE"),
         @Result(property = "executor", column = "EXECUTOR"),
-        @Result(property = "arguments", column = "ARGUMENTS", jdbcType = JdbcType.CLOB,
+        @Result(property = "arguments", column = "ARGUMENTS",
             javaType = Map.class, typeHandler = MapTypeHandler.class)
     })
     List<Job> findJobsToRun();
diff --git a/lib/taskana-core/src/main/java/pro/taskana/mappings/QueryMapper.java b/lib/taskana-core/src/main/java/pro/taskana/mappings/QueryMapper.java
index f372760cd..bb10d0ed8 100644
--- a/lib/taskana-core/src/main/java/pro/taskana/mappings/QueryMapper.java
+++ b/lib/taskana-core/src/main/java/pro/taskana/mappings/QueryMapper.java
@@ -32,9 +32,9 @@ public interface QueryMapper {
         + "<where>"
         + "<if test='accessIdIn != null'> "
         + "AND t.WORKBASKET_ID IN ( "
-        + "select WID from (select WORKBASKET_ID as WID, max(PERM_READ) as MAX_READ FROM TASKANA.WORKBASKET_ACCESS_LIST where "
+        + "SELECT WID from (SELECT WORKBASKET_ID as WID, MAX(PERM_READ::int) as MAX_READ FROM TASKANA.WORKBASKET_ACCESS_LIST AS s    where "
         + "ACCESS_ID IN (<foreach item='item' collection='accessIdIn' separator=',' >#{item}</foreach>) "
-        + "group by WORKBASKET_ID ) where max_read = 1 ) "
+        + "group by WORKBASKET_ID ) AS f where max_read = 1 ) "
         + "</if> "
         + "<if test='taskIds != null'>AND t.ID IN(<foreach item='item' collection='taskIds' separator=',' >#{item}</foreach>)</if> "
         + "<if test='createdIn !=null'> AND ( <foreach item='item' collection='createdIn' separator=' OR ' > ( <if test='item.begin!=null'> t.CREATED &gt;= #{item.begin} </if> <if test='item.begin!=null and item.end!=null'> AND </if><if test='item.end!=null'> t.CREATED &lt;=#{item.end} </if>)</foreach>)</if> "
@@ -234,10 +234,10 @@ public interface QueryMapper {
         + "SELECT DISTINCT "
         + "w.ID, w.KEY, w.NAME, w.DOMAIN, W.TYPE, w.DESCRIPTION, w.OWNER, w.ORG_LEVEL_1, w.ORG_LEVEL_2, w.ORG_LEVEL_3, w.ORG_LEVEL_4 from TASKANA.WORKBASKET w "
         + "<if test = 'joinWithAccessList'> "
-        + "LEFT OUTER JOIN (select WORKBASKET_ID as WID, max(PERM_READ) as MAX_READ, max(PERM_OPEN) as MAX_OPEN,  "
-        + "MAX(PERM_APPEND) as MAX_APPEND, MAX(PERM_TRANSFER) as MAX_TRANSFER, MAX(PERM_DISTRIBUTE) as MAX_DISTRIBUTE, MAX(PERM_CUSTOM_1) as MAX_CUSTOM_1, MAX(PERM_CUSTOM_2) as MAX_CUSTOM_2, "
-        + "MAX(PERM_CUSTOM_3) as MAX_CUSTOM_3, MAX(PERM_CUSTOM_4) as MAX_CUSTOM_4, MAX(PERM_CUSTOM_5) as MAX_CUSTOM_5, MAX(PERM_CUSTOM_6) as MAX_CUSTOM_6, MAX(PERM_CUSTOM_7) as MAX_CUSTOM_7, "
-        + "MAX(PERM_CUSTOM_8) as MAX_CUSTOM_8, MAX(PERM_CUSTOM_9) as MAX_CUSTOM_9, MAX(PERM_CUSTOM_10) as MAX_CUSTOM_10, MAX(PERM_CUSTOM_11) as MAX_CUSTOM_11, MAX(PERM_CUSTOM_12) as MAX_CUSTOM_12 "
+        + "LEFT OUTER JOIN (select WORKBASKET_ID as WID, MAX(PERM_READ::int) as MAX_READ, MAX(PERM_OPEN::int) as MAX_OPEN,  "
+        + "MAX(PERM_APPEND::int) as MAX_APPEND, MAX(PERM_TRANSFER::int) as MAX_TRANSFER, MAX(PERM_DISTRIBUTE::int) as MAX_DISTRIBUTE, MAX(PERM_CUSTOM_1::int) as MAX_CUSTOM_1, MAX(PERM_CUSTOM_2::int) as MAX_CUSTOM_2, "
+        + "MAX(PERM_CUSTOM_3::int) as MAX_CUSTOM_3, MAX(PERM_CUSTOM_4::int) as MAX_CUSTOM_4, MAX(PERM_CUSTOM_5::int) as MAX_CUSTOM_5, MAX(PERM_CUSTOM_6::int) as MAX_CUSTOM_6, MAX(PERM_CUSTOM_7::int) as MAX_CUSTOM_7, "
+        + "MAX(PERM_CUSTOM_8::int) as MAX_CUSTOM_8, MAX(PERM_CUSTOM_9::int) as MAX_CUSTOM_9, MAX(PERM_CUSTOM_10::int) as MAX_CUSTOM_10, MAX(PERM_CUSTOM_11::int) as MAX_CUSTOM_11, MAX(PERM_CUSTOM_12::int) as MAX_CUSTOM_12 "
         + "FROM TASKANA.WORKBASKET_ACCESS_LIST where ACCESS_ID IN (<if test='accessId != null'><foreach item='item' collection='accessId' separator=',' >#{item}</foreach></if>) group by WORKBASKET_ID ) a "
         + "on (w.ID = a.WID)"
         + "</if> "
@@ -357,9 +357,9 @@ public interface QueryMapper {
         + "<where>"
         + "<if test='accessIdIn != null'> "
         + "AND t.WORKBASKET_ID IN ( "
-        + "select WID from (select WORKBASKET_ID as WID, max(PERM_READ) as MAX_READ FROM TASKANA.WORKBASKET_ACCESS_LIST where "
+        + "select WID from (select WORKBASKET_ID as WID, MAX(PERM_READ::int) as MAX_READ FROM TASKANA.WORKBASKET_ACCESS_LIST AS s where "
         + "ACCESS_ID IN (<foreach item='item' collection='accessIdIn' separator=',' >#{item}</foreach>) "
-        + "group by WORKBASKET_ID ) where max_read = 1 ) "
+        + "group by WORKBASKET_ID ) AS f where max_read = 1 ) "
         + "</if> "
         + "<if test='taskIds != null'>AND t.ID IN(<foreach item='item' collection='taskIds' separator=',' >#{item}</foreach>)</if> "
         + "<if test='createdIn !=null'> AND ( <foreach item='item' collection='createdIn' separator=' OR ' > ( <if test='item.begin!=null'> t.CREATED &gt;= #{item.begin} </if> <if test='item.begin!=null and item.end!=null'> AND </if><if test='item.end!=null'> t.CREATED &lt;=#{item.end} </if>)</foreach>)</if> "
@@ -493,10 +493,10 @@ public interface QueryMapper {
     @Select("<script>"
         + "SELECT COUNT(w.ID) from TASKANA.WORKBASKET w "
         + "<if test = 'joinWithAccessList'> "
-        + "LEFT OUTER JOIN (select WORKBASKET_ID as WID, max(PERM_READ) as MAX_READ, max(PERM_OPEN) as MAX_OPEN,  "
-        + "MAX(PERM_APPEND) as MAX_APPEND, MAX(PERM_TRANSFER) as MAX_TRANSFER, MAX(PERM_DISTRIBUTE) as MAX_DISTRIBUTE, MAX(PERM_CUSTOM_1) as MAX_CUSTOM_1, MAX(PERM_CUSTOM_2) as MAX_CUSTOM_2, "
-        + "MAX(PERM_CUSTOM_3) as MAX_CUSTOM_3, MAX(PERM_CUSTOM_4) as MAX_CUSTOM_4, MAX(PERM_CUSTOM_5) as MAX_CUSTOM_5, MAX(PERM_CUSTOM_6) as MAX_CUSTOM_6, MAX(PERM_CUSTOM_7) as MAX_CUSTOM_7, "
-        + "MAX(PERM_CUSTOM_8) as MAX_CUSTOM_8, MAX(PERM_CUSTOM_9) as MAX_CUSTOM_9, MAX(PERM_CUSTOM_10) as MAX_CUSTOM_10, MAX(PERM_CUSTOM_11) as MAX_CUSTOM_11, MAX(PERM_CUSTOM_12) as MAX_CUSTOM_12 "
+        + "LEFT OUTER JOIN (select WORKBASKET_ID as WID, MAX(PERM_READ::int) as MAX_READ, MAX(PERM_OPEN::int) as MAX_OPEN,  "
+        + "MAX(PERM_APPEND::int) as MAX_APPEND, MAX(PERM_TRANSFER::int) as MAX_TRANSFER, MAX(PERM_DISTRIBUTE::int) as MAX_DISTRIBUTE, MAX(PERM_CUSTOM_1::int) as MAX_CUSTOM_1, MAX(PERM_CUSTOM_2::int) as MAX_CUSTOM_2, "
+        + "MAX(PERM_CUSTOM_3::int) as MAX_CUSTOM_3, MAX(PERM_CUSTOM_4::int) as MAX_CUSTOM_4, MAX(PERM_CUSTOM_5::int) as MAX_CUSTOM_5, MAX(PERM_CUSTOM_6::int) as MAX_CUSTOM_6, MAX(PERM_CUSTOM_7::int) as MAX_CUSTOM_7, "
+        + "MAX(PERM_CUSTOM_8::int) as MAX_CUSTOM_8, MAX(PERM_CUSTOM_9::int) as MAX_CUSTOM_9, MAX(PERM_CUSTOM_10::int) as MAX_CUSTOM_10, MAX(PERM_CUSTOM_11::int) as MAX_CUSTOM_11, MAX(PERM_CUSTOM_12::int) as MAX_CUSTOM_12 "
         + "FROM TASKANA.WORKBASKET_ACCESS_LIST where ACCESS_ID IN (<if test='accessId != null'><foreach item='item' collection='accessId' separator=',' >#{item}</foreach></if>) group by WORKBASKET_ID ) a "
         + "on (w.ID = a.WID)"
         + "</if> "
@@ -577,7 +577,7 @@ public interface QueryMapper {
         + "<where>"
         + "<if test='accessIdIn != null'> "
         + "AND t.WORKBASKET_ID IN ( "
-        + "select WID from (select WORKBASKET_ID as WID, max(PERM_READ) as MAX_READ FROM TASKANA.WORKBASKET_ACCESS_LIST where "
+        + "select WID from (select WORKBASKET_ID as WID, MAX(PERM_READ) as MAX_READ FROM TASKANA.WORKBASKET_ACCESS_LIST where "
         + "ACCESS_ID IN (<foreach item='item' collection='accessIdIn' separator=',' >#{item}</foreach>) "
         + "group by WORKBASKET_ID ) where max_read = 1 ) "
         + "</if> "
@@ -717,10 +717,10 @@ public interface QueryMapper {
     @Select("<script>SELECT DISTINCT ${columnName} "
         + "FROM TASKANA.WORKBASKET w "
         + "<if test = 'joinWithAccessList'> "
-        + "LEFT OUTER JOIN (select WORKBASKET_ID as WID, max(PERM_READ) as MAX_READ, max(PERM_OPEN) as MAX_OPEN,  "
-        + "MAX(PERM_APPEND) as MAX_APPEND, MAX(PERM_TRANSFER) as MAX_TRANSFER, MAX(PERM_DISTRIBUTE) as MAX_DISTRIBUTE, MAX(PERM_CUSTOM_1) as MAX_CUSTOM_1, MAX(PERM_CUSTOM_2) as MAX_CUSTOM_2, "
-        + "MAX(PERM_CUSTOM_3) as MAX_CUSTOM_3, MAX(PERM_CUSTOM_4) as MAX_CUSTOM_4, MAX(PERM_CUSTOM_5) as MAX_CUSTOM_5, MAX(PERM_CUSTOM_6) as MAX_CUSTOM_6, MAX(PERM_CUSTOM_7) as MAX_CUSTOM_7, "
-        + "MAX(PERM_CUSTOM_8) as MAX_CUSTOM_8, MAX(PERM_CUSTOM_9) as MAX_CUSTOM_9, MAX(PERM_CUSTOM_10) as MAX_CUSTOM_10, MAX(PERM_CUSTOM_11) as MAX_CUSTOM_11, MAX(PERM_CUSTOM_12) as MAX_CUSTOM_12 "
+        + "LEFT OUTER JOIN (select WORKBASKET_ID as WID, MAX(PERM_READ::int) as MAX_READ, MAX(PERM_OPEN::int) as MAX_OPEN,  "
+        + "MAX(PERM_APPEND::int) as MAX_APPEND, MAX(PERM_TRANSFER::int) as MAX_TRANSFER, MAX(PERM_DISTRIBUTE::int) as MAX_DISTRIBUTE, MAX(PERM_CUSTOM_1::int) as MAX_CUSTOM_1, MAX(PERM_CUSTOM_2::int) as MAX_CUSTOM_2, "
+        + "MAX(PERM_CUSTOM_3::int) as MAX_CUSTOM_3, MAX(PERM_CUSTOM_4::int) as MAX_CUSTOM_4, MAX(PERM_CUSTOM_5::int) as MAX_CUSTOM_5, MAX(PERM_CUSTOM_6::int) as MAX_CUSTOM_6, MAX(PERM_CUSTOM_7::int) as MAX_CUSTOM_7, "
+        + "MAX(PERM_CUSTOM_8::int) as MAX_CUSTOM_8, MAX(PERM_CUSTOM_9::int) as MAX_CUSTOM_9, MAX(PERM_CUSTOM_10::int) as MAX_CUSTOM_10, MAX(PERM_CUSTOM_11::int) as MAX_CUSTOM_11, MAX(PERM_CUSTOM_12::int) as MAX_CUSTOM_12 "
         + "FROM TASKANA.WORKBASKET_ACCESS_LIST where ACCESS_ID IN (<if test='accessId != null'><foreach item='item' collection='accessId' separator=',' >#{item}</foreach></if>) group by WORKBASKET_ID ) a "
         + "on (w.ID = a.WID)"
         + "</if> "
@@ -779,7 +779,15 @@ public interface QueryMapper {
         + "<if test=\"permission.name() == 'CUSTOM_9'\">a.MAX_CUSTOM_9</if>"
         + "<if test=\"permission.name() == 'CUSTOM_10'\">a.MAX_CUSTOM_10</if>"
         + "<if test=\"permission.name() == 'CUSTOM_11'\">a.MAX_CUSTOM_11</if>"
-        + "<if test=\"permission.name() == 'CUSTOM_12'\">a.MAX_CUSTOM_12</if> = 1 "
+        + "<if test=\"permission.name() == 'CUSTOM_12'\">a.MAX_CUSTOM_12</if>"
+        + "<choose>"
+        + "<when test=\"_databaseId == 'postgres'\">"
+        + "= TRUE "
+        + "</when>"
+        + "<otherwise>"
+        + "= 1 "
+        + "</otherwise>"
+        + "</choose>"
         + "</if>)"
         + "</if>"
         + "</where>"
diff --git a/lib/taskana-core/src/main/java/pro/taskana/mappings/TaskMapper.java b/lib/taskana-core/src/main/java/pro/taskana/mappings/TaskMapper.java
index 1b152889a..da7ec89fc 100644
--- a/lib/taskana-core/src/main/java/pro/taskana/mappings/TaskMapper.java
+++ b/lib/taskana-core/src/main/java/pro/taskana/mappings/TaskMapper.java
@@ -11,7 +11,6 @@ import org.apache.ibatis.annotations.Result;
 import org.apache.ibatis.annotations.Results;
 import org.apache.ibatis.annotations.Select;
 import org.apache.ibatis.annotations.Update;
-import org.apache.ibatis.type.JdbcType;
 
 import pro.taskana.impl.MinimalTaskSummary;
 import pro.taskana.impl.TaskImpl;
@@ -59,9 +58,9 @@ public interface TaskMapper {
         @Result(property = "primaryObjRef.value", column = "POR_VALUE"),
         @Result(property = "isRead", column = "IS_READ"),
         @Result(property = "isTransferred", column = "IS_TRANSFERRED"),
-        @Result(property = "callbackInfo", column = "CALLBACK_INFO", jdbcType = JdbcType.CLOB,
+        @Result(property = "callbackInfo", column = "CALLBACK_INFO",
             javaType = Map.class, typeHandler = MapTypeHandler.class),
-        @Result(property = "customAttributes", column = "CUSTOM_ATTRIBUTES", jdbcType = JdbcType.CLOB,
+        @Result(property = "customAttributes", column = "CUSTOM_ATTRIBUTES",
             javaType = Map.class, typeHandler = MapTypeHandler.class),
         @Result(property = "custom1", column = "CUSTOM_1"),
         @Result(property = "custom2", column = "CUSTOM_2"),
@@ -184,7 +183,9 @@ public interface TaskMapper {
         @Param("referencetask") TaskSummaryImpl referencetask);
 
     @Select("<script>SELECT ID, STATE, WORKBASKET_ID FROM TASKANA.TASK "
-        + "WHERE ID IN(<foreach item='item' collection='taskIds' separator=',' >#{item}</foreach>) "
+        + "<if test=\" taskIds != null and !taskIds.isEmpty() \">"
+        + "WHERE ID IN( <foreach item='item' collection='taskIds' separator=',' >#{item}</foreach> ) "
+        + "</if>"
         + "<if test=\"_databaseId == 'db2'\">with UR </if> "
         + "</script>")
     @Results(value = {
diff --git a/lib/taskana-core/src/main/java/pro/taskana/mappings/TaskMonitorMapper.java b/lib/taskana-core/src/main/java/pro/taskana/mappings/TaskMonitorMapper.java
index 24b12852f..0357a2085 100644
--- a/lib/taskana-core/src/main/java/pro/taskana/mappings/TaskMonitorMapper.java
+++ b/lib/taskana-core/src/main/java/pro/taskana/mappings/TaskMonitorMapper.java
@@ -23,6 +23,7 @@ public interface TaskMonitorMapper {
     @Select("<script>"
         + "<if test=\"_databaseId == 'db2'\">SELECT WORKBASKET_KEY, (DAYS(DUE) - DAYS(CURRENT_TIMESTAMP)) as AGE_IN_DAYS, COUNT(*) as NUMBER_OF_TASKS</if> "
         + "<if test=\"_databaseId == 'h2'\">SELECT WORKBASKET_KEY, DATEDIFF('DAY', CURRENT_TIMESTAMP, DUE) as AGE_IN_DAYS, COUNT(*) as NUMBER_OF_TASKS</if> "
+        + "<if test=\"_databaseId == 'postgres'\">SELECT WORKBASKET_KEY, DATE_PART('DAY', DUE - CURRENT_TIMESTAMP) as AGE_IN_DAYS, COUNT(*) as NUMBER_OF_TASKS</if> "
         + "FROM TASKANA.TASK "
         + "<where>"
         + "<if test=\"workbasketIds != null\">"
@@ -44,6 +45,7 @@ public interface TaskMonitorMapper {
         + "</where>"
         + "<if test=\"_databaseId == 'db2'\">GROUP BY WORKBASKET_KEY, (DAYS(DUE) - DAYS(CURRENT_TIMESTAMP))</if> "
         + "<if test=\"_databaseId == 'h2'\">GROUP BY WORKBASKET_KEY, DATEDIFF('DAY', CURRENT_TIMESTAMP, DUE)</if> "
+        + "<if test=\"_databaseId == 'postgres'\">GROUP BY WORKBASKET_KEY, DATE_PART('DAY', DUE - CURRENT_TIMESTAMP)</if> "
         + "<if test=\"_databaseId == 'db2'\">with UR </if> "
         + "</script>")
     @Results({
@@ -60,6 +62,7 @@ public interface TaskMonitorMapper {
     @Select("<script>"
         + "<if test=\"_databaseId == 'db2'\">SELECT CLASSIFICATION_CATEGORY, (DAYS(DUE) - DAYS(CURRENT_TIMESTAMP)) as AGE_IN_DAYS, COUNT(*) as NUMBER_OF_TASKS</if> "
         + "<if test=\"_databaseId == 'h2'\">SELECT CLASSIFICATION_CATEGORY, DATEDIFF('DAY', CURRENT_TIMESTAMP, DUE) as AGE_IN_DAYS, COUNT(*) as NUMBER_OF_TASKS</if> "
+        + "<if test=\"_databaseId == 'postgres'\">SELECT CLASSIFICATION_CATEGORY, DATE_PART('DAY', DUE - CURRENT_TIMESTAMP) as AGE_IN_DAYS, COUNT(*) as NUMBER_OF_TASKS</if> "
         + "FROM TASKANA.TASK "
         + "<where>"
         + "<if test=\"workbasketIds != null\">"
@@ -81,6 +84,7 @@ public interface TaskMonitorMapper {
         + "</where>"
         + "<if test=\"_databaseId == 'db2'\">GROUP BY CLASSIFICATION_CATEGORY, (DAYS(DUE) - DAYS(CURRENT_TIMESTAMP))</if> "
         + "<if test=\"_databaseId == 'h2'\">GROUP BY CLASSIFICATION_CATEGORY, DATEDIFF('DAY', CURRENT_TIMESTAMP, DUE)</if> "
+        + "<if test=\"_databaseId == 'postgres'\">GROUP BY CLASSIFICATION_CATEGORY, DATE_PART('DAY', DUE - CURRENT_TIMESTAMP)</if> "
         + "<if test=\"_databaseId == 'db2'\">with UR </if> "
         + "</script>")
     @Results({
@@ -97,6 +101,7 @@ public interface TaskMonitorMapper {
     @Select("<script>"
         + "<if test=\"_databaseId == 'db2'\">SELECT CLASSIFICATION_KEY, (DAYS(DUE) - DAYS(CURRENT_TIMESTAMP)) as AGE_IN_DAYS, COUNT(*) as NUMBER_OF_TASKS</if> "
         + "<if test=\"_databaseId == 'h2'\">SELECT CLASSIFICATION_KEY, DATEDIFF('DAY', CURRENT_TIMESTAMP, DUE) as AGE_IN_DAYS, COUNT(*) as NUMBER_OF_TASKS</if> "
+        + "<if test=\"_databaseId == 'postgres'\">SELECT CLASSIFICATION_KEY, DATE_PART('DAY', DUE - CURRENT_TIMESTAMP) as AGE_IN_DAYS, COUNT(*) as NUMBER_OF_TASKS</if> "
         + "FROM TASKANA.TASK "
         + "<where>"
         + "<if test=\"workbasketIds != null\">"
@@ -118,6 +123,7 @@ public interface TaskMonitorMapper {
         + "</where>"
         + "<if test=\"_databaseId == 'db2'\">GROUP BY CLASSIFICATION_KEY, (DAYS(DUE) - DAYS(CURRENT_TIMESTAMP))</if> "
         + "<if test=\"_databaseId == 'h2'\">GROUP BY CLASSIFICATION_KEY, DATEDIFF('DAY', CURRENT_TIMESTAMP, DUE)</if> "
+        + "<if test=\"_databaseId == 'postgres'\">GROUP BY CLASSIFICATION_KEY, DATE_PART('DAY', DUE - CURRENT_TIMESTAMP)</if> "
         + "<if test=\"_databaseId == 'db2'\">with UR </if> "
         + "</script>")
     @Results({
@@ -134,6 +140,7 @@ public interface TaskMonitorMapper {
     @Select("<script>"
         + "<if test=\"_databaseId == 'db2'\">SELECT T.CLASSIFICATION_KEY as TASK_CLASSIFICATION_KEY, A.CLASSIFICATION_KEY as ATTACHMENT_CLASSIFICATION_KEY, (DAYS(DUE) - DAYS(CURRENT_TIMESTAMP)) as AGE_IN_DAYS, COUNT(*) as NUMBER_OF_TASKS</if> "
         + "<if test=\"_databaseId == 'h2'\">SELECT T.CLASSIFICATION_KEY as TASK_CLASSIFICATION_KEY, A.CLASSIFICATION_KEY as ATTACHMENT_CLASSIFICATION_KEY, DATEDIFF('DAY', CURRENT_TIMESTAMP, DUE) as AGE_IN_DAYS, COUNT(*) as NUMBER_OF_TASKS</if> "
+        + "<if test=\"_databaseId == 'postgres'\">SELECT T.CLASSIFICATION_KEY as TASK_CLASSIFICATION_KEY, A.CLASSIFICATION_KEY as ATTACHMENT_CLASSIFICATION_KEY, DATE_PART('DAY', DUE - CURRENT_TIMESTAMP) as AGE_IN_DAYS, COUNT(*) as NUMBER_OF_TASKS</if> "
         + "FROM TASKANA.TASK AS T LEFT JOIN TASKANA.ATTACHMENT AS A ON T.ID = A.TASK_ID "
         + "<where>"
         + "<if test=\"workbasketIds != null\">"
@@ -155,6 +162,7 @@ public interface TaskMonitorMapper {
         + "</where>"
         + "<if test=\"_databaseId == 'db2'\">GROUP BY T.CLASSIFICATION_KEY, A.CLASSIFICATION_KEY, (DAYS(DUE) - DAYS(CURRENT_TIMESTAMP))</if> "
         + "<if test=\"_databaseId == 'h2'\">GROUP BY T.CLASSIFICATION_KEY, A.CLASSIFICATION_KEY, DATEDIFF('DAY', CURRENT_TIMESTAMP, DUE)</if> "
+        + "<if test=\"_databaseId == 'postgres'\">GROUP BY T.CLASSIFICATION_KEY, A.CLASSIFICATION_KEY, DATE_PART('DAY', DUE - CURRENT_TIMESTAMP)</if> "
         + "<if test=\"_databaseId == 'db2'\">with UR </if> "
         + "</script>")
     @Results({
@@ -173,6 +181,7 @@ public interface TaskMonitorMapper {
     @Select("<script>"
         + "<if test=\"_databaseId == 'db2'\">SELECT ${customField} as CUSTOM_FIELD, (DAYS(DUE) - DAYS(CURRENT_TIMESTAMP)) as AGE_IN_DAYS, COUNT(*) as NUMBER_OF_TASKS</if> "
         + "<if test=\"_databaseId == 'h2'\">SELECT ${customField} as CUSTOM_FIELD, DATEDIFF('DAY', CURRENT_TIMESTAMP, DUE) as AGE_IN_DAYS, COUNT(*) as NUMBER_OF_TASKS</if> "
+        + "<if test=\"_databaseId == 'postgres'\">SELECT ${customField} as CUSTOM_FIELD, DATE_PART('DAY', DUE - CURRENT_TIMESTAMP) as AGE_IN_DAYS, COUNT(*) as NUMBER_OF_TASKS</if> "
         + "FROM TASKANA.TASK "
         + "<where>"
         + "<if test=\"workbasketIds != null\">"
@@ -194,6 +203,7 @@ public interface TaskMonitorMapper {
         + "</where>"
         + "<if test=\"_databaseId == 'db2'\">GROUP BY ${customField}, (DAYS(DUE) - DAYS(CURRENT_TIMESTAMP))</if> "
         + "<if test=\"_databaseId == 'h2'\">GROUP BY ${customField}, DATEDIFF('DAY', CURRENT_TIMESTAMP, DUE)</if> "
+        + "<if test=\"_databaseId == 'postgres'\">GROUP BY ${customField}, DATE_PART('DAY', DUE - CURRENT_TIMESTAMP)</if> "
         + "<if test=\"_databaseId == 'db2'\">with UR </if> "
         + "</script>")
     @Results({
@@ -248,6 +258,10 @@ public interface TaskMonitorMapper {
         + "#{selectedItem.upperAgeLimit} >= DATEDIFF('DAY', CURRENT_TIMESTAMP, DUE) AND "
         + "#{selectedItem.lowerAgeLimit} &lt;= DATEDIFF('DAY', CURRENT_TIMESTAMP, DUE) "
         + "</if> "
+        + "<if test=\"_databaseId == 'postgres'\">"
+        + "#{selectedItem.upperAgeLimit} >= DATE_PART('day', DUE - CURRENT_TIMESTAMP ) AND "
+        + "#{selectedItem.lowerAgeLimit} &lt;= DATE_PART('day', DUE - CURRENT_TIMESTAMP ) "
+        + "</if> "
         + "</foreach>) "
         + "</where>"
         + "<if test=\"_databaseId == 'db2'\">with UR </if> "
diff --git a/lib/taskana-core/src/main/java/pro/taskana/mappings/WorkbasketAccessMapper.java b/lib/taskana-core/src/main/java/pro/taskana/mappings/WorkbasketAccessMapper.java
index c72055dd6..b209e6957 100644
--- a/lib/taskana-core/src/main/java/pro/taskana/mappings/WorkbasketAccessMapper.java
+++ b/lib/taskana-core/src/main/java/pro/taskana/mappings/WorkbasketAccessMapper.java
@@ -90,7 +90,8 @@ public interface WorkbasketAccessMapper {
     @Delete("DELETE FROM TASKANA.WORKBASKET_ACCESS_LIST where ACCESS_ID = #{accessId}")
     void deleteAccessItemsForAccessId(@Param("accessId") String accessId);
 
-    @Select("<script>SELECT MAX(PERM_READ) AS P_READ, MAX(PERM_OPEN) AS P_OPEN, MAX(PERM_APPEND) AS P_APPEND, MAX(PERM_TRANSFER) AS P_TRANSFER, MAX(PERM_DISTRIBUTE) AS P_DISTRIBUTE, MAX(PERM_CUSTOM_1) AS P_CUSTOM_1, MAX(PERM_CUSTOM_2) AS P_CUSTOM_2, MAX(PERM_CUSTOM_3) AS P_CUSTOM_3, MAX(PERM_CUSTOM_4) AS P_CUSTOM_4, MAX(PERM_CUSTOM_5) AS P_CUSTOM_5, MAX(PERM_CUSTOM_6) AS P_CUSTOM_6, MAX(PERM_CUSTOM_7) AS P_CUSTOM_7, MAX(PERM_CUSTOM_8) AS P_CUSTOM_8, MAX(PERM_CUSTOM_9) AS P_CUSTOM_9, MAX(PERM_CUSTOM_10) AS P_CUSTOM_10, MAX(PERM_CUSTOM_11) AS P_CUSTOM_11, MAX(PERM_CUSTOM_12) AS P_CUSTOM_12 "
+    @Select("<script>"
+        + "SELECT MAX(PERM_READ::int) AS P_READ, MAX(PERM_OPEN::int) AS P_OPEN, MAX(PERM_APPEND::int) AS P_APPEND, MAX(PERM_TRANSFER::int) AS P_TRANSFER, MAX(PERM_DISTRIBUTE::int) AS P_DISTRIBUTE, MAX(PERM_CUSTOM_1::int) AS P_CUSTOM_1, MAX(PERM_CUSTOM_2::int) AS P_CUSTOM_2, MAX(PERM_CUSTOM_3::int) AS P_CUSTOM_3, MAX(PERM_CUSTOM_4::int) AS P_CUSTOM_4, MAX(PERM_CUSTOM_5::int) AS P_CUSTOM_5, MAX(PERM_CUSTOM_6::int) AS P_CUSTOM_6, MAX(PERM_CUSTOM_7::int) AS P_CUSTOM_7, MAX(PERM_CUSTOM_8::int) AS P_CUSTOM_8, MAX(PERM_CUSTOM_9::int) AS P_CUSTOM_9, MAX(PERM_CUSTOM_10::int) AS P_CUSTOM_10, MAX(PERM_CUSTOM_11::int) AS P_CUSTOM_11, MAX(PERM_CUSTOM_12::int) AS P_CUSTOM_12 "
         + "FROM TASKANA.WORKBASKET_ACCESS_LIST "
         + "WHERE WORKBASKET_ID = #{workbasketId} "
         + "AND ACCESS_ID IN(<foreach item='item' collection='accessIds' separator=',' >#{item}</foreach>) "
@@ -120,7 +121,8 @@ public interface WorkbasketAccessMapper {
     WorkbasketAccessItemImpl findByWorkbasketAndAccessId(
         @Param("workbasketId") String workbasketId, @Param("accessIds") List<String> accessIds);
 
-    @Select("<script>SELECT MAX(PERM_READ) AS P_READ, MAX(PERM_OPEN) AS P_OPEN, MAX(PERM_APPEND) AS P_APPEND, MAX(PERM_TRANSFER) AS P_TRANSFER, MAX(PERM_DISTRIBUTE) AS P_DISTRIBUTE, MAX(PERM_CUSTOM_1) AS P_CUSTOM_1, MAX(PERM_CUSTOM_2) AS P_CUSTOM_2, MAX(PERM_CUSTOM_3) AS P_CUSTOM_3, MAX(PERM_CUSTOM_4) AS P_CUSTOM_4, MAX(PERM_CUSTOM_5) AS P_CUSTOM_5, MAX(PERM_CUSTOM_6) AS P_CUSTOM_6, MAX(PERM_CUSTOM_7) AS P_CUSTOM_7, MAX(PERM_CUSTOM_8) AS P_CUSTOM_8, MAX(PERM_CUSTOM_9) AS P_CUSTOM_9, MAX(PERM_CUSTOM_10) AS P_CUSTOM_10, MAX(PERM_CUSTOM_11) AS P_CUSTOM_11, MAX(PERM_CUSTOM_12) AS P_CUSTOM_12 "
+    @Select("<script>"
+        + "SELECT MAX(PERM_READ::int) AS P_READ, MAX(PERM_OPEN::int) AS P_OPEN, MAX(PERM_APPEND::int) AS P_APPEND, MAX(PERM_TRANSFER::int) AS P_TRANSFER, MAX(PERM_DISTRIBUTE::int) AS P_DISTRIBUTE, MAX(PERM_CUSTOM_1::int) AS P_CUSTOM_1, MAX(PERM_CUSTOM_2::int) AS P_CUSTOM_2, MAX(PERM_CUSTOM_3::int) AS P_CUSTOM_3, MAX(PERM_CUSTOM_4::int) AS P_CUSTOM_4, MAX(PERM_CUSTOM_5::int) AS P_CUSTOM_5, MAX(PERM_CUSTOM_6::int) AS P_CUSTOM_6, MAX(PERM_CUSTOM_7::int) AS P_CUSTOM_7, MAX(PERM_CUSTOM_8::int) AS P_CUSTOM_8, MAX(PERM_CUSTOM_9::int) AS P_CUSTOM_9, MAX(PERM_CUSTOM_10::int) AS P_CUSTOM_10, MAX(PERM_CUSTOM_11::int) AS P_CUSTOM_11, MAX(PERM_CUSTOM_12::int) AS P_CUSTOM_12 "
         + "FROM TASKANA.WORKBASKET_ACCESS_LIST "
         + "WHERE WORKBASKET_ID in (SELECT ID FROM TASKANA.WORKBASKET WHERE KEY = #{workbasketKey} AND DOMAIN = #{domain} )  "
         + "AND ACCESS_ID IN(<foreach item='item' collection='accessIds' separator=',' >#{item}</foreach>) "
diff --git a/lib/taskana-core/src/main/resources/sql/taskana-schema-postgres.sql b/lib/taskana-core/src/main/resources/sql/taskana-schema-postgres.sql
new file mode 100644
index 000000000..675dce7fc
--- /dev/null
+++ b/lib/taskana-core/src/main/resources/sql/taskana-schema-postgres.sql
@@ -0,0 +1,187 @@
+CREATE SCHEMA IF NOT EXISTS TASKANA;
+
+CREATE TABLE TASKANA.TASKANA_SCHEMA_VERSION(
+        ID CHAR(40) NOT NULL,
+        VERSION VARCHAR(255) NOT NULL,
+        PRIMARY KEY (ID)
+);
+INSERT INTO TASKANA.TASKANA_SCHEMA_VERSION VALUES ('1', '0.1.2');
+
+CREATE TABLE TASKANA.CLASSIFICATION(
+    ID CHAR(40) NOT NULL,
+    KEY VARCHAR(32) NOT NULL,
+    PARENT_ID VARCHAR(40) NOT NULL,
+    CATEGORY VARCHAR(32),
+    TYPE VARCHAR(32),
+    DOMAIN VARCHAR(255) NOT NULL,
+    VALID_IN_DOMAIN BOOLEAN NOT NULL,
+    CREATED TIMESTAMP NULL,
+    MODIFIED TIMESTAMP NULL,
+    NAME VARCHAR(255) NULL,
+    DESCRIPTION VARCHAR(255) NULL,
+    PRIORITY INT NOT NULL,
+    SERVICE_LEVEL VARCHAR(255) NULL,
+    APPLICATION_ENTRY_POINT VARCHAR(255) NULL,
+    CUSTOM_1 VARCHAR(255) NULL,
+    CUSTOM_2 VARCHAR(255) NULL,
+    CUSTOM_3 VARCHAR(255) NULL,
+    CUSTOM_4 VARCHAR(255) NULL,
+    CUSTOM_5 VARCHAR(255) NULL,
+    CUSTOM_6 VARCHAR(255) NULL,
+    CUSTOM_7 VARCHAR(255) NULL,
+    CUSTOM_8 VARCHAR(255) NULL,
+    PRIMARY KEY (ID),
+    CONSTRAINT UC_CLASS_KEY_DOMAIN UNIQUE (KEY, DOMAIN)
+);
+
+CREATE TABLE TASKANA.WORKBASKET(
+    ID CHAR(40) NOT NULL,
+    KEY VARCHAR(64) NOT NULL,
+    CREATED TIMESTAMP NULL,
+    MODIFIED TIMESTAMP NULL,
+    NAME VARCHAR(255) NOT NULL,
+    DOMAIN VARCHAR(32) NOT NULL,
+    TYPE VARCHAR(16) NOT NULL,
+    DESCRIPTION VARCHAR(255) NULL,
+    OWNER VARCHAR(128) NULL,
+    CUSTOM_1 VARCHAR(255) NULL,
+    CUSTOM_2 VARCHAR(255) NULL,
+    CUSTOM_3 VARCHAR(255) NULL,
+    CUSTOM_4 VARCHAR(255) NULL,
+    ORG_LEVEL_1 VARCHAR(255) NULL,
+    ORG_LEVEL_2 VARCHAR(255) NULL,
+    ORG_LEVEL_3 VARCHAR(255) NULL,
+    ORG_LEVEL_4 VARCHAR(255) NULL,
+    PRIMARY KEY (ID),
+    CONSTRAINT WB_KEY_DOMAIN UNIQUE (KEY, DOMAIN)
+);
+
+CREATE TABLE TASKANA.TASK (
+        ID CHAR(40) NOT NULL,
+        CREATED TIMESTAMP NULL,
+        CLAIMED TIMESTAMP NULL,
+        COMPLETED TIMESTAMP NULL,
+        MODIFIED TIMESTAMP NULL,
+        PLANNED TIMESTAMP NULL,
+        DUE TIMESTAMP NULL,
+        NAME VARCHAR(255) NULL,
+        CREATOR VARCHAR(32) NULL,
+        DESCRIPTION VARCHAR(1024) NULL,
+        NOTE VARCHAR(4096) NULL,
+        PRIORITY INT NULL,
+        STATE VARCHAR(20) NULL,
+        CLASSIFICATION_CATEGORY VARCHAR(32) NULL,
+        CLASSIFICATION_KEY VARCHAR(32) NULL,
+        CLASSIFICATION_ID CHAR(40) NULL,
+        WORKBASKET_ID CHAR(40) NULL,
+        WORKBASKET_KEY VARCHAR(64) NULL,
+        DOMAIN VARCHAR(32) NULL,
+        BUSINESS_PROCESS_ID VARCHAR(128) NULL,
+        PARENT_BUSINESS_PROCESS_ID VARCHAR(128) NULL,
+        OWNER VARCHAR(32) NULL,
+        POR_COMPANY VARCHAR(32) NOT NULL,
+        POR_SYSTEM VARCHAR(32) NOT NULL,
+        POR_INSTANCE VARCHAR(32) NOT NULL,
+        POR_TYPE VARCHAR(32) NOT NULL,
+        POR_VALUE VARCHAR(128) NOT NULL,
+        IS_READ BOOLEAN NOT NULL,
+        IS_TRANSFERRED BOOLEAN NOT NULL,
+        CALLBACK_INFO TEXT NULL,
+        CUSTOM_ATTRIBUTES TEXT NULL,
+        CUSTOM_1 VARCHAR(255) NULL,
+        CUSTOM_2 VARCHAR(255) NULL,
+        CUSTOM_3 VARCHAR(255) NULL,
+        CUSTOM_4 VARCHAR(255) NULL,
+        CUSTOM_5 VARCHAR(255) NULL,
+        CUSTOM_6 VARCHAR(255) NULL,
+        CUSTOM_7 VARCHAR(255) NULL,
+        CUSTOM_8 VARCHAR(255) NULL,
+        CUSTOM_9 VARCHAR(255) NULL,
+        CUSTOM_10 VARCHAR(255) NULL,
+        CUSTOM_11 VARCHAR(255) NULL,
+        CUSTOM_12 VARCHAR(255) NULL,
+        CUSTOM_13 VARCHAR(255) NULL,
+        CUSTOM_14 VARCHAR(255) NULL,
+        CUSTOM_15 VARCHAR(255) NULL,
+        CUSTOM_16 VARCHAR(255) NULL,
+        PRIMARY KEY (ID),
+        CONSTRAINT TASK_WB FOREIGN KEY  (WORKBASKET_ID) REFERENCES TASKANA.WORKBASKET ON DELETE NO ACTION,
+        CONSTRAINT TASK_CLASS FOREIGN KEY (CLASSIFICATION_ID) REFERENCES TASKANA.CLASSIFICATION ON DELETE NO ACTION
+);
+
+CREATE TABLE TASKANA.DISTRIBUTION_TARGETS(
+        SOURCE_ID CHAR(40) NOT NULL,
+        TARGET_ID CHAR(40) NOT NULL,
+        PRIMARY KEY (SOURCE_ID, TARGET_ID)
+);
+
+CREATE TABLE TASKANA.WORKBASKET_ACCESS_LIST(
+        ID CHAR(40) NOT NULL,
+        WORKBASKET_ID CHAR(40) NOT NULL,
+        ACCESS_ID VARCHAR(255) NOT NULL,
+        PERM_READ BOOLEAN NOT NULL,
+        PERM_OPEN BOOLEAN NOT NULL,
+        PERM_APPEND BOOLEAN NOT NULL,
+        PERM_TRANSFER BOOLEAN NOT NULL,
+        PERM_DISTRIBUTE BOOLEAN NOT NULL,
+        PERM_CUSTOM_1 BOOLEAN NOT NULL,
+        PERM_CUSTOM_2 BOOLEAN NOT NULL,
+        PERM_CUSTOM_3 BOOLEAN NOT NULL,
+        PERM_CUSTOM_4 BOOLEAN NOT NULL,
+        PERM_CUSTOM_5 BOOLEAN NOT NULL,
+        PERM_CUSTOM_6 BOOLEAN NOT NULL,
+        PERM_CUSTOM_7 BOOLEAN NOT NULL,
+        PERM_CUSTOM_8 BOOLEAN NOT NULL,
+        PERM_CUSTOM_9 BOOLEAN NOT NULL,
+        PERM_CUSTOM_10 BOOLEAN NOT NULL,
+        PERM_CUSTOM_11 BOOLEAN NOT NULL,
+        PERM_CUSTOM_12 BOOLEAN NOT NULL,
+        PRIMARY KEY (ID),
+        CONSTRAINT ACCESS_LIST_WB FOREIGN KEY  (WORKBASKET_ID) REFERENCES TASKANA.WORKBASKET ON DELETE CASCADE
+);
+
+CREATE TABLE TASKANA.OBJECT_REFERENCE(
+        ID CHAR(40) NOT NULL,
+        COMPANY VARCHAR(32) NOT NULL,
+        SYSTEM VARCHAR(32) NOT NULL,
+        SYSTEM_INSTANCE VARCHAR(32) NOT NULL,
+        TYPE VARCHAR(32) NOT NULL,
+        VALUE VARCHAR(128) NOT NULL
+);
+
+CREATE TABLE TASKANA.ATTACHMENT(
+    ID CHAR(40) NOT NULL,
+    TASK_ID CHAR(40) NOT NULL,
+    CREATED TIMESTAMP NULL,
+    MODIFIED TIMESTAMP NULL,
+    CLASSIFICATION_KEY VARCHAR(32) NULL,
+    CLASSIFICATION_ID CHAR(40) NULL,
+    REF_COMPANY VARCHAR(32) NOT NULL,
+    REF_SYSTEM VARCHAR(32) NOT NULL,
+    REF_INSTANCE VARCHAR(32) NOT NULL,
+    REF_TYPE VARCHAR(32) NOT NULL,
+    REF_VALUE VARCHAR(128) NOT NULL,
+    CHANNEL VARCHAR(64) NULL,
+    RECEIVED TIMESTAMP NULL,
+    CUSTOM_ATTRIBUTES TEXT NULL,
+    PRIMARY KEY (ID),
+    CONSTRAINT ATT_CLASS FOREIGN KEY (CLASSIFICATION_ID) REFERENCES TASKANA.CLASSIFICATION ON DELETE NO ACTION
+);
+
+CREATE TABLE TASKANA.JOB(
+        JOB_ID          INTEGER NOT NULL,
+        CREATED         TIMESTAMP NULL,
+        STARTED         TIMESTAMP NULL,
+        COMPLETED       TIMESTAMP NULL,
+        STATE           VARCHAR(32) NULL,
+        EXECUTOR        VARCHAR(128) NOT NULL,
+        ARGUMENTS       TEXT NULL,
+        PRIMARY KEY (JOB_ID)
+);
+
+CREATE SEQUENCE TASKANA.JOB_SEQ
+  MINVALUE 1
+  START WITH 1
+  INCREMENT BY 1
+  CACHE 10;
+
diff --git a/lib/taskana-core/src/test/java/acceptance/AbstractAccTest.java b/lib/taskana-core/src/test/java/acceptance/AbstractAccTest.java
index 2d1e89392..ce4c3404e 100644
--- a/lib/taskana-core/src/test/java/acceptance/AbstractAccTest.java
+++ b/lib/taskana-core/src/test/java/acceptance/AbstractAccTest.java
@@ -23,7 +23,6 @@ import pro.taskana.database.TestDataGenerator;
 import pro.taskana.exceptions.ClassificationNotFoundException;
 import pro.taskana.exceptions.NotAuthorizedException;
 import pro.taskana.impl.ObjectReference;
-import pro.taskana.impl.TaskanaEngineImpl;
 import pro.taskana.impl.configuration.DBCleaner;
 import pro.taskana.impl.configuration.TaskanaEngineConfigurationTest;
 
@@ -51,7 +50,7 @@ public abstract class AbstractAccTest {
         dataSource = TaskanaEngineConfigurationTest.getDataSource();
         taskanaEngineConfiguration = new TaskanaEngineConfiguration(dataSource, false);
         taskanaEngine = taskanaEngineConfiguration.buildTaskanaEngine();
-        ((TaskanaEngineImpl) taskanaEngine).setConnectionManagementMode(ConnectionManagementMode.AUTOCOMMIT);
+        taskanaEngine.setConnectionManagementMode(ConnectionManagementMode.AUTOCOMMIT);
         cleaner.clearDb(dataSource, false);
         TestDataGenerator testDataGenerator = new TestDataGenerator();
         testDataGenerator.generateTestData(dataSource);
diff --git a/lib/taskana-core/src/test/java/acceptance/workbasket/DistributionTargetsAccTest.java b/lib/taskana-core/src/test/java/acceptance/workbasket/DistributionTargetsAccTest.java
index cc29ef2ab..3fc6281a7 100644
--- a/lib/taskana-core/src/test/java/acceptance/workbasket/DistributionTargetsAccTest.java
+++ b/lib/taskana-core/src/test/java/acceptance/workbasket/DistributionTargetsAccTest.java
@@ -218,7 +218,7 @@ public class DistributionTargetsAccTest extends AbstractAccTest {
         groupNames = {"group_1", "group_2", "businessadmin"})
     @Test
     public void testSetDistributionTargets()
-        throws NotAuthorizedException, WorkbasketNotFoundException, InvalidWorkbasketException, SQLException {
+        throws NotAuthorizedException, WorkbasketNotFoundException, SQLException {
         WorkbasketService workbasketService = taskanaEngine.getWorkbasketService();
 
         Workbasket sourceWorkbasket = workbasketService.getWorkbasket("GPK_KSC_1", "DOMAIN_A");
@@ -232,8 +232,9 @@ public class DistributionTargetsAccTest extends AbstractAccTest {
             .list();
         assertEquals(2, newDistributionTargets.size());
 
-        List<String> newDistributionTargetIds = newDistributionTargets.stream().map(t -> t.getId()).collect(
-            Collectors.toList());
+        List<String> newDistributionTargetIds = newDistributionTargets.stream()
+            .map(WorkbasketSummary::getId)
+            .collect(Collectors.toList());
 
         workbasketService.setDistributionTargets(sourceWorkbasket.getId(), newDistributionTargetIds);
         List<WorkbasketSummary> changedTargets = workbasketService.getDistributionTargets(sourceWorkbasket.getId());
diff --git a/lib/taskana-core/src/test/java/pro/taskana/impl/integration/ClassificationServiceImplIntExplicitTest.java b/lib/taskana-core/src/test/java/pro/taskana/impl/integration/ClassificationServiceImplIntExplicitTest.java
index 97634152b..befe404b0 100644
--- a/lib/taskana-core/src/test/java/pro/taskana/impl/integration/ClassificationServiceImplIntExplicitTest.java
+++ b/lib/taskana-core/src/test/java/pro/taskana/impl/integration/ClassificationServiceImplIntExplicitTest.java
@@ -436,7 +436,7 @@ public class ClassificationServiceImplIntExplicitTest {
     }
 
     @After
-    public void cleanUp() {
+    public void cleanUp() throws SQLException {
         taskanaEngineImpl.setConnection(null);
     }
 
diff --git a/lib/taskana-core/src/test/java/pro/taskana/impl/integration/TaskServiceImplIntExplicitTest.java b/lib/taskana-core/src/test/java/pro/taskana/impl/integration/TaskServiceImplIntExplicitTest.java
index e7df49497..75a8c5e19 100644
--- a/lib/taskana-core/src/test/java/pro/taskana/impl/integration/TaskServiceImplIntExplicitTest.java
+++ b/lib/taskana-core/src/test/java/pro/taskana/impl/integration/TaskServiceImplIntExplicitTest.java
@@ -490,7 +490,7 @@ public class TaskServiceImplIntExplicitTest {
     }
 
     @After
-    public void cleanUp() {
+    public void cleanUp() throws SQLException {
         taskanaEngineImpl.setConnection(null);
     }
 }
diff --git a/lib/taskana-core/src/test/java/pro/taskana/impl/integration/WorkbasketServiceImplIntExplicitTest.java b/lib/taskana-core/src/test/java/pro/taskana/impl/integration/WorkbasketServiceImplIntExplicitTest.java
index da55d5926..5f57240bb 100644
--- a/lib/taskana-core/src/test/java/pro/taskana/impl/integration/WorkbasketServiceImplIntExplicitTest.java
+++ b/lib/taskana-core/src/test/java/pro/taskana/impl/integration/WorkbasketServiceImplIntExplicitTest.java
@@ -189,7 +189,7 @@ public class WorkbasketServiceImplIntExplicitTest {
     }
 
     @After
-    public void cleanUp() {
+    public void cleanUp() throws SQLException {
         taskanaEngineImpl.setConnection(null);
     }
 
diff --git a/lib/taskana-core/src/test/java/pro/taskana/mappings/TaskTestMapper.java b/lib/taskana-core/src/test/java/pro/taskana/mappings/TaskTestMapper.java
index 5f6670ac0..6b67e6292 100644
--- a/lib/taskana-core/src/test/java/pro/taskana/mappings/TaskTestMapper.java
+++ b/lib/taskana-core/src/test/java/pro/taskana/mappings/TaskTestMapper.java
@@ -8,7 +8,6 @@ import org.apache.ibatis.annotations.Result;
 import org.apache.ibatis.annotations.Results;
 import org.apache.ibatis.annotations.Select;
 import org.apache.ibatis.type.ClobTypeHandler;
-import org.apache.ibatis.type.JdbcType;
 
 import pro.taskana.impl.TaskImpl;
 import pro.taskana.impl.persistence.MapTypeHandler;
@@ -20,7 +19,7 @@ public interface TaskTestMapper {
 
     @Select("select CUSTOM_ATTRIBUTES from TASKANA.TASK where id = #{taskId}")
     @Results(value = {
-        @Result(property = "customAttributes", column = "CUSTOM_ATTRIBUTES", jdbcType = JdbcType.CLOB,
+        @Result(property = "customAttributes", column = "CUSTOM_ATTRIBUTES",
             javaType = String.class, typeHandler = ClobTypeHandler.class)
     })
     String getCustomAttributesAsString(@Param("taskId") String taskId);
@@ -56,7 +55,7 @@ public interface TaskTestMapper {
         @Result(property = "primaryObjRef.value", column = "POR_VALUE"),
         @Result(property = "isRead", column = "IS_READ"),
         @Result(property = "isTransferred", column = "IS_TRANSFERRED"),
-        @Result(property = "customAttributes", column = "CUSTOM_ATTRIBUTES", jdbcType = JdbcType.CLOB,
+        @Result(property = "customAttributes", column = "CUSTOM_ATTRIBUTES",
             javaType = Map.class, typeHandler = MapTypeHandler.class),
         @Result(property = "custom1", column = "CUSTOM_1"),
         @Result(property = "custom2", column = "CUSTOM_2"),
diff --git a/lib/taskana-core/src/test/resources/sql/clear-db.sql b/lib/taskana-core/src/test/resources/sql/clear-db.sql
index 768b4b7c9..d850b6746 100644
--- a/lib/taskana-core/src/test/resources/sql/clear-db.sql
+++ b/lib/taskana-core/src/test/resources/sql/clear-db.sql
@@ -1,9 +1,10 @@
+-- the order is important!
+DELETE FROM TASKANA.ATTACHMENT;
 DELETE FROM TASKANA.TASK;
 DELETE FROM TASKANA.WORKBASKET_ACCESS_LIST;
 DELETE FROM TASKANA.WORKBASKET;
 DELETE FROM TASKANA.DISTRIBUTION_TARGETS;
 DELETE FROM TASKANA.CLASSIFICATION;
 DELETE FROM TASKANA.OBJECT_REFERENCE;
-DELETE FROM TASKANA.ATTACHMENT;
 DELETE FROM TASKANA.JOB;
 COMMIT;
diff --git a/lib/taskana-core/src/test/resources/sql/drop-tables.sql b/lib/taskana-core/src/test/resources/sql/drop-tables.sql
index d7073c28e..a8639fc26 100644
--- a/lib/taskana-core/src/test/resources/sql/drop-tables.sql
+++ b/lib/taskana-core/src/test/resources/sql/drop-tables.sql
@@ -1,11 +1,11 @@
-DROP TABLE TASKANA.TASKANA_SCHEMA_VERSION;
-DROP TABLE TASKANA.TASK;
-DROP TABLE TASKANA.WORKBASKET_ACCESS_LIST;
-DROP TABLE TASKANA.WORKBASKET;
-DROP TABLE TASKANA.DISTRIBUTION_TARGETS;
-DROP TABLE TASKANA.CLASSIFICATION;
-DROP TABLE TASKANA.OBJECT_REFERENCE;
-DROP TABLE TASKANA.ATTACHMENT;
-DROP TABLE TASKANA.JOB;
+DROP TABLE TASKANA.TASKANA_SCHEMA_VERSION CASCADE;
+DROP TABLE TASKANA.TASK CASCADE;
+DROP TABLE TASKANA.WORKBASKET_ACCESS_LIST CASCADE;
+DROP TABLE TASKANA.WORKBASKET CASCADE;
+DROP TABLE TASKANA.DISTRIBUTION_TARGETS CASCADE;
+DROP TABLE TASKANA.CLASSIFICATION CASCADE;
+DROP TABLE TASKANA.OBJECT_REFERENCE CASCADE;
+DROP TABLE TASKANA.ATTACHMENT CASCADE;
+DROP TABLE TASKANA.JOB CASCADE;
 DROP SEQUENCE TASKANA.JOB_SEQ;
 COMMIT;
diff --git a/rest/taskana-rest-spring-example/pom.xml b/rest/taskana-rest-spring-example/pom.xml
index b8f65ea89..d5a4b9e23 100644
--- a/rest/taskana-rest-spring-example/pom.xml
+++ b/rest/taskana-rest-spring-example/pom.xml
@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <project xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-	xmlns="http://maven.apache.org/POM/4.0.0"
-	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+		 xmlns="http://maven.apache.org/POM/4.0.0"
+		 xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
 	<modelVersion>4.0.0</modelVersion>
 
 	<groupId>pro.taskana</groupId>
@@ -31,7 +31,7 @@
 			<artifactId>taskana-rest-spring</artifactId>
 			<version>${project.version}</version>
 		</dependency>
-		
+
 		<!-- Tests -->
 		<dependency>
 			<groupId>org.springframework.boot</groupId>