diff --git a/dump/src/main/java/eu/dnetlib/dhp/oa/graph/dump/subset/ReadMasterDuplicateFromDB.java b/dump/src/main/java/eu/dnetlib/dhp/oa/graph/dump/subset/ReadMasterDuplicateFromDB.java
index d379730..d606800 100644
--- a/dump/src/main/java/eu/dnetlib/dhp/oa/graph/dump/subset/ReadMasterDuplicateFromDB.java
+++ b/dump/src/main/java/eu/dnetlib/dhp/oa/graph/dump/subset/ReadMasterDuplicateFromDB.java
@@ -2,6 +2,7 @@
 package eu.dnetlib.dhp.oa.graph.dump.subset;
 
 import com.fasterxml.jackson.databind.ObjectMapper;
+import com.mongodb.DBCursor;
 import eu.dnetlib.dhp.application.ArgumentApplicationParser;
 import eu.dnetlib.dhp.common.DbClient;
 import eu.dnetlib.dhp.schema.oaf.utils.OafMapperUtils;
@@ -23,13 +24,9 @@ import java.sql.ResultSet;
 import java.sql.SQLException;
 import java.util.function.Function;
 
-public class ReadMasterDuplicateFromDB implements Closeable {
+public class ReadMasterDuplicateFromDB  {
 
-	private final DbClient dbClient;
-	private static final Log log = LogFactory.getLog(ReadMasterDuplicateFromDB.class);
-
-	private final BufferedWriter writer;
-	private final ObjectMapper OBJECT_MAPPER = new ObjectMapper();
+	private static final ObjectMapper OBJECT_MAPPER = new ObjectMapper();
 
 	private static final String QUERY = "SELECT id as master, duplicate FROM dsm_dedup_services; ";
 
@@ -49,31 +46,37 @@ public class ReadMasterDuplicateFromDB implements Closeable {
 		final String hdfsPath = parser.get("hdfsPath");
 		final String hdfsNameNode = parser.get("hdfsNameNode");
 
-		try (
-			final ReadMasterDuplicateFromDB rmd = new ReadMasterDuplicateFromDB(hdfsPath, hdfsNameNode, dbUrl, dbUser,
-				dbPassword)) {
+		Configuration conf = new Configuration();
+		conf.set("fs.defaultFS", hdfsNameNode);
 
-			log.info("Processing datasources...");
-			rmd.execute(QUERY, rmd::datasourceMasterMap);
+		FileSystem fileSystem = FileSystem.get(conf);
+		Path hdfsWritePath = new Path(hdfsPath);
+		FSDataOutputStream fsDataOutputStream = fileSystem.create(hdfsWritePath);
 
+		execute(dbUrl, dbUser, dbPassword, fsDataOutputStream);
+
+	}
+
+	private static void execute(String dbUrl, String dbUser, String dbPassword, FSDataOutputStream fos) {
+		try(DbClient dbClient = new DbClient(dbUrl, dbUser, dbPassword)){
+			try(BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(fos, StandardCharsets.UTF_8))){
+				dbClient.processResults(QUERY, rs ->  writeMap(datasourceMasterMap(rs), writer));
+			}
+
+		} catch (IOException e) {
+			e.printStackTrace();
 		}
 	}
 
-	public void execute(final String sql, final Function<ResultSet, MasterDuplicate> producer) {
 
-		dbClient.processResults(sql, rs -> writeMap(producer.apply(rs)));
-	}
-
-	public MasterDuplicate datasourceMasterMap(ResultSet rs) {
+	public static MasterDuplicate datasourceMasterMap(ResultSet rs) {
 		try {
 			MasterDuplicate dm = new MasterDuplicate();
 			String duplicate = rs.getString("duplicate");
-			dm.setDuplicate(duplicate);
+			dm.setDuplicate(OafMapperUtils.createOpenaireId(10, duplicate, true));
 			String master = rs.getString("master");
-			if (StringUtils.isNotBlank(master))
-				dm.setMaster(OafMapperUtils.createOpenaireId(10, master, true));
-			else
-				dm.setMaster(OafMapperUtils.createOpenaireId(10, duplicate, true));
+			dm.setMaster(OafMapperUtils.createOpenaireId(10, master, true));
+
 			return dm;
 
 		} catch (final SQLException e) {
@@ -81,34 +84,8 @@ public class ReadMasterDuplicateFromDB implements Closeable {
 		}
 	}
 
-	@Override
-	public void close() throws IOException {
-		dbClient.close();
-		writer.close();
-	}
 
-	public ReadMasterDuplicateFromDB(
-		final String hdfsPath, String hdfsNameNode, final String dbUrl, final String dbUser, final String dbPassword)
-		throws IOException {
-
-		this.dbClient = new DbClient(dbUrl, dbUser, dbPassword);
-
-		Configuration conf = new Configuration();
-		conf.set("fs.defaultFS", hdfsNameNode);
-
-		FileSystem fileSystem = FileSystem.get(conf);
-		Path hdfsWritePath = new Path(hdfsPath);
-		FSDataOutputStream fsDataOutputStream = null;
-		if (fileSystem.exists(hdfsWritePath)) {
-			fsDataOutputStream = fileSystem.append(hdfsWritePath);
-		} else {
-			fsDataOutputStream = fileSystem.create(hdfsWritePath);
-		}
-
-		this.writer = new BufferedWriter(new OutputStreamWriter(fsDataOutputStream, StandardCharsets.UTF_8));
-	}
-
-	protected void writeMap(final MasterDuplicate dm) {
+	protected static void writeMap(final MasterDuplicate dm, BufferedWriter writer) {
 		try {
 			writer.write(OBJECT_MAPPER.writeValueAsString(dm));
 			writer.newLine();
diff --git a/dump/src/main/resources/eu/dnetlib/dhp/oa/graph/dump/wf/subworkflows/subset/oozie_app/workflow.xml b/dump/src/main/resources/eu/dnetlib/dhp/oa/graph/dump/wf/subworkflows/subset/oozie_app/workflow.xml
index 0244be9..2fe7c96 100644
--- a/dump/src/main/resources/eu/dnetlib/dhp/oa/graph/dump/wf/subworkflows/subset/oozie_app/workflow.xml
+++ b/dump/src/main/resources/eu/dnetlib/dhp/oa/graph/dump/wf/subworkflows/subset/oozie_app/workflow.xml
@@ -8,11 +8,18 @@
             <name>outputPath</name>
             <description>the output path</description>
         </property>
-
         <property>
             <name>organizationCommunityMap</name>
             <description>the organization community map</description>
         </property>
+        <property>
+            <name>pathMap</name>
+            <description>the path where to find the elements involved in the constraints within the json</description>
+        </property>
+        <property>
+            <name>selectionCriteria</name>
+            <description>the selection criteria used to select the results</description>
+        </property>
 
         <property>
             <name>hiveDbName</name>