diff --git a/src/main/java/org/gcube/accounting/analytics/persistence/postgresql/AccountingPersistenceQueryPostgreSQL.java b/src/main/java/org/gcube/accounting/analytics/persistence/postgresql/AccountingPersistenceQueryPostgreSQL.java
index eb608bb..240da02 100644
--- a/src/main/java/org/gcube/accounting/analytics/persistence/postgresql/AccountingPersistenceQueryPostgreSQL.java
+++ b/src/main/java/org/gcube/accounting/analytics/persistence/postgresql/AccountingPersistenceQueryPostgreSQL.java
@@ -61,7 +61,7 @@ public class AccountingPersistenceQueryPostgreSQL implements AccountingPersisten
 	protected TemporalConstraint temporalConstraint;
 	
 	protected Set<String> contexts;
-	protected Set<Filter> filters;
+	protected List<Filter> filters;
 	
 	
 	public AccountingPersistenceQueryPostgreSQL() {
@@ -84,7 +84,7 @@ public class AccountingPersistenceQueryPostgreSQL implements AccountingPersisten
 	}
 	
 	@Override
-	public void setFilters(Set<Filter> filters) {
+	public void setFilters(List<Filter> filters) {
 		this.filters = filters;
 	}
 	
diff --git a/src/main/java/org/gcube/accounting/analytics/persistence/postgresql/Query.java b/src/main/java/org/gcube/accounting/analytics/persistence/postgresql/Query.java
index 8955213..ee17d09 100644
--- a/src/main/java/org/gcube/accounting/analytics/persistence/postgresql/Query.java
+++ b/src/main/java/org/gcube/accounting/analytics/persistence/postgresql/Query.java
@@ -7,6 +7,7 @@ import java.util.Calendar;
 import java.util.Collection;
 import java.util.HashMap;
 import java.util.HashSet;
+import java.util.List;
 import java.util.Map;
 import java.util.Set;
 
@@ -56,7 +57,7 @@ public class Query extends PostgreSQLQuery {
 		this.temporalConstraint = temporalConstraint;
 	}
 
-	public void setFilters(Collection<Filter> filters) {
+	public void setFilters(List<Filter> filters) {
 		this.filters = new HashMap<>();
 		if(filters!=null && filters.size()>0) {
 			for(Filter filter : filters) {
diff --git a/src/test/java/org/gcube/accounting/analytics/persistence/postgresql/AccountingPersistenceQueryPostgreSQLTest.java b/src/test/java/org/gcube/accounting/analytics/persistence/postgresql/AccountingPersistenceQueryPostgreSQLTest.java
index dea9dbe..3841c0b 100644
--- a/src/test/java/org/gcube/accounting/analytics/persistence/postgresql/AccountingPersistenceQueryPostgreSQLTest.java
+++ b/src/test/java/org/gcube/accounting/analytics/persistence/postgresql/AccountingPersistenceQueryPostgreSQLTest.java
@@ -54,8 +54,8 @@ public class AccountingPersistenceQueryPostgreSQLTest extends ContextTest {
 		accountingPersistenceQueryPostgreSQL.prepareConnection(configuration);
 	}
 	
-	protected Set<Filter> getFilters(){
-		Set<Filter> filters = new HashSet<>();
+	protected List<Filter> getFilters(){
+		List<Filter> filters = new ArrayList<>();
 		String user = QueryTest.getRandomUser();
 		logger.debug("Going to query filtering with user {}", user);
 		Filter filter = new Filter(UsageRecord.CONSUMER_ID, user);
@@ -95,7 +95,7 @@ public class AccountingPersistenceQueryPostgreSQLTest extends ContextTest {
 	@Test
 	public void testGetNoContextTimeSeries() throws Exception {
 		
-		Set<Filter> filters = getFilters();
+		List<Filter> filters = getFilters();
 		
 		TemporalConstraint temporalConstraint = getTemporalConstraint();
 		
@@ -119,7 +119,7 @@ public class AccountingPersistenceQueryPostgreSQLTest extends ContextTest {
 	
 	@Test
 	public void testTimeSeries() throws DuplicatedKeyFilterException, KeyException, ValueException, Exception {
-		Set<Filter> filters = getFilters();
+		List<Filter> filters = getFilters();
 		
 		TemporalConstraint temporalConstraint = getTemporalConstraint();
 		
@@ -147,7 +147,7 @@ public class AccountingPersistenceQueryPostgreSQLTest extends ContextTest {
 	@Test
 	public void testContextTimeSeries() throws DuplicatedKeyFilterException, KeyException, ValueException, Exception {
 		
-		Set<Filter> filters = getFilters();
+		List<Filter> filters = getFilters();
 		
 		TemporalConstraint temporalConstraint = getTemporalConstraint();
 		
@@ -184,7 +184,7 @@ public class AccountingPersistenceQueryPostgreSQLTest extends ContextTest {
 	@Test
 	public void testGetFilterValues() throws DuplicatedKeyFilterException, KeyException, ValueException, Exception {
 		
-		Set<Filter> filters = getFilters();
+		List<Filter> filters = getFilters();
 		
 		TemporalConstraint temporalConstraint = getTemporalConstraint();
 		
@@ -222,7 +222,7 @@ public class AccountingPersistenceQueryPostgreSQLTest extends ContextTest {
 	public void testTopValues() throws DuplicatedKeyFilterException, KeyException, ValueException, Exception {	
 		String orderingProperty = AccountingPersistenceQuery.getDefaultOrderingProperties(AggregatedServiceUsageRecord.class);
 		
-		Set<Filter> filters = new HashSet<>();
+		List<Filter> filters = new ArrayList<>();
 		Filter filter = new Filter(UsageRecord.CONSUMER_ID, QueryTest.getRandomUser());
 		filters.add(filter);
 		
diff --git a/src/test/java/org/gcube/accounting/analytics/persistence/postgresql/QueryTest.java b/src/test/java/org/gcube/accounting/analytics/persistence/postgresql/QueryTest.java
index fca5c4f..afbf92d 100644
--- a/src/test/java/org/gcube/accounting/analytics/persistence/postgresql/QueryTest.java
+++ b/src/test/java/org/gcube/accounting/analytics/persistence/postgresql/QueryTest.java
@@ -3,8 +3,10 @@
  */
 package org.gcube.accounting.analytics.persistence.postgresql;
 
+import java.util.ArrayList;
 import java.util.Calendar;
 import java.util.HashSet;
+import java.util.List;
 import java.util.Random;
 import java.util.Set;
 
@@ -54,7 +56,7 @@ public class QueryTest extends ContextTest {
 		entTimeCalendar.set(Calendar.HOUR_OF_DAY, 16);
 		entTimeCalendar.set(Calendar.MINUTE, 17);
 		
-		Set<Filter> filters = new HashSet<>();
+		List<Filter> filters = new ArrayList<>();
 		Filter filter = new Filter(UsageRecord.CONSUMER_ID, getRandomUser());
 		filters.add(filter);
 		filter = new Filter(UsageRecord.CONSUMER_ID, getRandomUser());