Added a sleep of 3 milliseconds to slow down the record read so mitigate

the overload on couchbase

src/main/java/org/gcube/accounting/aggregator/aggregation/Aggregator.java

@@ -5,6 +5,7 @@ import java.text.DateFormat;
 import java.util.Calendar;
 import java.util.List;
 import java.util.UUID;
+import java.util.concurrent.TimeUnit;
 
 import org.gcube.accounting.aggregator.status.AggregationState;
 import org.gcube.accounting.aggregator.status.AggregationStatus;
@@ -236,6 +237,7 @@ public class Aggregator {
 			for(int i=1; i<=MAX_RETRY; i++){
 				try {
 					originalRecordsCounter = elaborateRow(row, aggregatorBuffer, originalRecordsCounter);
+					TimeUnit.MILLISECONDS.sleep(3);
 					break;
 				}catch (RuntimeException e) {
 					if(i==2){