diff --git a/src/main/java/org/gcube/accounting/analytics/ResourceRecordQuery.java b/src/main/java/org/gcube/accounting/analytics/ResourceRecordQuery.java
index 7260062..8016963 100644
--- a/src/main/java/org/gcube/accounting/analytics/ResourceRecordQuery.java
+++ b/src/main/java/org/gcube/accounting/analytics/ResourceRecordQuery.java
@@ -159,4 +159,14 @@ public class ResourceRecordQuery {
 		return getInfo(usageRecordType, temporalConstraint, filters, false);
 	}
 	
+	/**
+	 * Return the list of key valid for queries a certain usage record type
+	 * @param usageRecordType the usage record type 
+	 * @return a set containing the list of key
+	 * @throws Exception if fails
+	 */
+	public Set<String> getFilterKeys(@SuppressWarnings("rawtypes") Class<? extends AggregatedUsageRecord> usageRecordType) throws Exception{
+		return accountingPersistenceQuery.getKeys(usageRecordType);
+	}
+	
 }
diff --git a/src/main/java/org/gcube/accounting/analytics/persistence/AccountingPersistenceQuery.java b/src/main/java/org/gcube/accounting/analytics/persistence/AccountingPersistenceQuery.java
index ece13f0..42c6484 100644
--- a/src/main/java/org/gcube/accounting/analytics/persistence/AccountingPersistenceQuery.java
+++ b/src/main/java/org/gcube/accounting/analytics/persistence/AccountingPersistenceQuery.java
@@ -6,6 +6,7 @@ package org.gcube.accounting.analytics.persistence;
 import java.util.Calendar;
 import java.util.List;
 import java.util.Map;
+import java.util.Set;
 
 import org.gcube.accounting.analytics.Filter;
 import org.gcube.accounting.analytics.Info;
@@ -27,6 +28,19 @@ public abstract class AccountingPersistenceQuery {
 	protected abstract Map<Calendar, Info> reallyQuery(@SuppressWarnings("rawtypes") Class<? extends AggregatedUsageRecord> usageRecordType, 
 			TemporalConstraint temporalConstraint, List<Filter> filters) throws Exception;
 	
+	/**
+	 * Query the persistence obtaining a Map where the date is the key and 
+	 * the #Info is the value. The result is relative to an Usage Record Type,
+	 * respect a TemporalConstraint and can be applied one or more filters.
+	 * @param usageRecordType the Usage Record Type of interest
+	 * @param temporalConstraint the TemporalConstraint (interval and aggregation)
+	 * @param filters the filter for the query. If null or empty string get all
+	 * data. The filters are evaluated in the order the are presented and are
+	 * considered in AND 
+	 * @return the Map containing for each date in the required interval the
+	 * requested data
+	 * @throws Exception if fails
+	 */
 	public Map<Calendar, Info> query(@SuppressWarnings("rawtypes") Class<? extends AggregatedUsageRecord> usageRecordType, 
 			TemporalConstraint temporalConstraint, List<Filter> filters) throws Exception{
 		logger.trace("Request query: UsageRecordType={}, {}={}, {}s={}", usageRecordType.newInstance().getUsageRecordType(), 
@@ -35,5 +49,13 @@ public abstract class AccountingPersistenceQuery {
 		return reallyQuery(usageRecordType, temporalConstraint, filters);
 	}
 	
+	/**
+	 * Return the list of key valid for queries a certain usage record type
+	 * @param usageRecordType the usage record type 
+	 * @return a set containing the list of key
+	 * @throws Exception if fails
+	 */
+	public abstract Set<String> getKeys(@SuppressWarnings("rawtypes") Class<? extends AggregatedUsageRecord> usageRecordType) throws Exception;
+	
 	public abstract void close() throws Exception;
 }