diff --git a/src/main/java/org/gcube/portal/databook/server/DBCassandraAstyanaxImpl.java b/src/main/java/org/gcube/portal/databook/server/DBCassandraAstyanaxImpl.java
index 8cbdc8f..dcc35bc 100644
--- a/src/main/java/org/gcube/portal/databook/server/DBCassandraAstyanaxImpl.java
+++ b/src/main/java/org/gcube/portal/databook/server/DBCassandraAstyanaxImpl.java
@@ -325,7 +325,10 @@ public final class DBCassandraAstyanaxImpl implements DatabookStore {
 			m.withRow(cf_VRETline, feed.getVreid())
 			.putColumn(feed.getTime().getTime()+"", feed.getKey().toString(), null);
 		}
-		return execute(m);
+		boolean result = execute(m);
+		if (result)
+			_log.trace("saveAppFeed OK!");
+		return result;
 	}
 	/**
 	 * {@inheritDoc}
diff --git a/src/main/java/org/gcube/portal/databook/server/RunningCluster.java b/src/main/java/org/gcube/portal/databook/server/RunningCluster.java
index 60eba61..628c329 100644
--- a/src/main/java/org/gcube/portal/databook/server/RunningCluster.java
+++ b/src/main/java/org/gcube/portal/databook/server/RunningCluster.java
@@ -2,20 +2,15 @@ package org.gcube.portal.databook.server;
 
 import java.io.IOException;
 import java.io.Serializable;
-import java.lang.reflect.MalformedParameterizedTypeException;
 import java.util.List;
 import java.util.Properties;
 
 import org.gcube.common.core.contexts.GHNContext;
-import org.gcube.common.core.informationsystem.ISException;
 import org.gcube.common.core.informationsystem.client.AtomicCondition;
 import org.gcube.common.core.informationsystem.client.ISClient;
-import org.gcube.common.core.informationsystem.client.ISClient.ISMalformedQueryException;
-import org.gcube.common.core.informationsystem.client.ISClient.ISUnsupportedQueryException;
 import org.gcube.common.core.informationsystem.client.queries.GCUBERuntimeResourceQuery;
 import org.gcube.common.core.resources.GCUBERuntimeResource;
 import org.gcube.common.core.scope.GCUBEScope;
-import org.gcube.common.core.scope.GCUBEScope.MalformedScopeExpressionException;
 import org.gcube.common.core.utils.logging.GCUBEClientLog;
 import org.gcube.portal.databook.shared.ex.TooManyRunningClustersException;
 /**