diff --git a/src/main/java/org/gcube/portlets/user/databasesmanager/client/utils/ConstantsPortlet.java b/src/main/java/org/gcube/portlets/user/databasesmanager/client/utils/ConstantsPortlet.java
index 823d10c..614c4c7 100644
--- a/src/main/java/org/gcube/portlets/user/databasesmanager/client/utils/ConstantsPortlet.java
+++ b/src/main/java/org/gcube/portlets/user/databasesmanager/client/utils/ConstantsPortlet.java
@@ -24,10 +24,16 @@ public class ConstantsPortlet {
 	public static final String DATABASE="Database";
 	public static final String SCHEMA="Schema";
 	
+	//algorithmID
+	public static final String ALGID_GETRESOURCE="LISTDBNAMES";
+	public static final String ALGID_GETDBINFO="LISTDBINFO";
+	public static final String ALGID_GETDBSCHEMA="LISTDBSCHEMA";
+	public static final String ALGID_GETTABLES="LISTTABLES";
+	public static final String ALGID_GETTABLEDETAILS="GETTABLEDETAILS";
 	public static final String ALGID_SUBMITQUERY="SUBMITQUERY";
 	public static final String ALGID_SAMPLEONTABLE="SAMPLEONTABLE";
 	public static final String ALGID_SMARTSAMPLEONTABLE="SMARTSAMPLEONTABLE";
-//	public static final String ALGID_RANDOMSAMPLEONTABLE="RANDOMSAMPLEONTABLE";
+	public static final String ALGID_RANDOMSAMPLEONTABLE="RANDOMSAMPLEONTABLE";
 	
 	
 	
diff --git a/src/main/java/org/gcube/portlets/user/databasesmanager/server/GWTdbManagerServiceImpl.java b/src/main/java/org/gcube/portlets/user/databasesmanager/server/GWTdbManagerServiceImpl.java
index b9ea1b2..573e47a 100644
--- a/src/main/java/org/gcube/portlets/user/databasesmanager/server/GWTdbManagerServiceImpl.java
+++ b/src/main/java/org/gcube/portlets/user/databasesmanager/server/GWTdbManagerServiceImpl.java
@@ -289,7 +289,7 @@ public class GWTdbManagerServiceImpl extends RemoteServiceServlet implements
 			List<FileModel> outputParameters = new ArrayList<FileModel>();
 
 			// get algorithmId
-			String algorithmId = "LISTDBNAMES";
+			String algorithmId = ConstantsPortlet.ALGID_GETRESOURCE;
 
 			Parameter maxNumber = new Parameter("MaxNumber", "", "String", "-1");
 			inputParameters.add(maxNumber);
@@ -377,7 +377,7 @@ public class GWTdbManagerServiceImpl extends RemoteServiceServlet implements
 			// data output
 			LinkedHashMap<String, FileModel> outputParameters = new LinkedHashMap<String, FileModel>();
 
-			String algorithmId = "LISTDBINFO";
+			String algorithmId = ConstantsPortlet.ALGID_GETDBINFO;
 
 			// print check
 			logger.info("dbmanager-> ResourceName: " + resourceName);
@@ -481,7 +481,7 @@ public class GWTdbManagerServiceImpl extends RemoteServiceServlet implements
 			// data output
 			List<FileModel> outputParameters = new ArrayList<FileModel>();
 
-			String algorithmId = "LISTDBSCHEMA";
+			String algorithmId = ConstantsPortlet.ALGID_GETDBSCHEMA;
 			// print check
 			String rs = dataInput.get("ResourceName");
 			String db = dataInput.get("DatabaseName");
@@ -592,7 +592,7 @@ public class GWTdbManagerServiceImpl extends RemoteServiceServlet implements
 			// data output
 			List<Result> outputParameters = new ArrayList<Result>();
 
-			String algorithmId = "LISTTABLES";
+			String algorithmId = ConstantsPortlet.ALGID_GETTABLES;
 
 			String rs = dataInput.get("ResourceName");
 			String db = dataInput.get("DatabaseName");
@@ -859,7 +859,7 @@ public class GWTdbManagerServiceImpl extends RemoteServiceServlet implements
 
 			// converted query
 			String convertedQuery = "";
-			String algorithmId = "SUBMITQUERY";
+			String algorithmId = ConstantsPortlet.ALGID_SUBMITQUERY;
 
 			// print check
 			String rs = dataDB.get("ResourceName");
@@ -1087,7 +1087,7 @@ public class GWTdbManagerServiceImpl extends RemoteServiceServlet implements
 			List<Result> output = new ArrayList<Result>();
 			SamplingResultWithFileFromServlet result;
 
-			String algorithmId = "SAMPLEONTABLE";
+			String algorithmId = ConstantsPortlet.ALGID_SAMPLEONTABLE;
 
 			// print check
 			String rs = dataInput.get("ResourceName");
@@ -1235,7 +1235,7 @@ public class GWTdbManagerServiceImpl extends RemoteServiceServlet implements
 			List<Result> output = new ArrayList<Result>();
 			SamplingResultWithFileFromServlet result;
 
-			String algorithmId = "SMARTSAMPLEONTABLE";
+			String algorithmId = ConstantsPortlet.ALGID_SMARTSAMPLEONTABLE;
 
 			// print check
 			String rs = dataInput.get("ResourceName");
@@ -1380,7 +1380,7 @@ public class GWTdbManagerServiceImpl extends RemoteServiceServlet implements
 			// output sample result
 			List<Result> output = new ArrayList<Result>();
 
-			String algorithmId = "RANDOMSAMPLEONTABLE";
+			String algorithmId = ConstantsPortlet.ALGID_RANDOMSAMPLEONTABLE;
 
 			// print check
 			String rs = dataInput.get("ResourceName");
@@ -1498,7 +1498,7 @@ public class GWTdbManagerServiceImpl extends RemoteServiceServlet implements
 			// data ouptut
 			LinkedHashMap<String, FileModel> outputParameters = new LinkedHashMap<String, FileModel>();
 
-			String algorithmId = "GETTABLEDETAILS";
+			String algorithmId = ConstantsPortlet.ALGID_GETTABLEDETAILS;
 
 			// print check
 			String rs = dataInput.get("ResourceName");
@@ -2237,7 +2237,7 @@ public class GWTdbManagerServiceImpl extends RemoteServiceServlet implements
 	}
 
 	private String getUsername() {
-		//set the username of the user session to value "database.manager"
+		// set the username of the user session to value "database.manager"
 		// HttpSession httpSession = this.getThreadLocalRequest().getSession();
 		// return SessionUtil.getUsername(httpSession);
 		return "database.manager";
@@ -2426,13 +2426,15 @@ public class GWTdbManagerServiceImpl extends RemoteServiceServlet implements
 						break;
 
 					case "schema":
+						
 						key = inputData.get("ResourceName")
 								+ inputData.get("DatabaseName")
 								+ inputData.get("SchemaName");
 
 						// refresh submitted query and samplings
 						keyUsedForQueryRefresh = ConstantsPortlet.ALGID_SUBMITQUERY
-								+ key;
+								+ inputData.get("ResourceName")
+								+ inputData.get("DatabaseName");
 						refreshSubmittedQueryInCache(keyUsedForQueryRefresh);
 						keyUsedForSamplingsRefresh = ConstantsPortlet.ALGID_SAMPLEONTABLE
 								+ key;
@@ -2486,7 +2488,7 @@ public class GWTdbManagerServiceImpl extends RemoteServiceServlet implements
 								getTables(inputData, ConstantsPortlet.DATABASE);
 
 							}
-							
+
 							break;
 
 						case "schema":
@@ -2530,6 +2532,8 @@ public class GWTdbManagerServiceImpl extends RemoteServiceServlet implements
 		// recover keys list that match the key
 		for (int i = 0; i < listSize; i++) {
 			if (keysInCache.get(i).startsWith(key)) {
+				// System.out.println("data removed with key: " +
+				// keysInCache.get(i));
 				keysToBeRemoved.add(keysInCache.get(i));
 			}
 		}
@@ -2556,7 +2560,9 @@ public class GWTdbManagerServiceImpl extends RemoteServiceServlet implements
 		}
 		// remove keys
 		DBCache.removeAll(keysToBeRemoved);
-		// System.out.println("Samplings refreshed with keys: "+keyUsedForSamplingsRefresh+" "+keyUsedForSmartSamplingRefresh);
+//		System.out.println("Samplings refreshed with keys: "
+//				+ keyUsedForSamplingsRefresh + " "
+//				+ keyUsedForSmartSamplingRefresh);
 	}
 
 	private String storeResultIntoCSVFile(List<Result> result, String n)
@@ -2611,7 +2617,8 @@ public class GWTdbManagerServiceImpl extends RemoteServiceServlet implements
 				.getSession());
 	}
 
-	//to delete more space occurences in order to have only one space between two words in a query
+	// to delete more space occurences in order to have only one space between
+	// two words in a query
 	private String parseQuery(String query) {
 		String queryParsed;