The system-defined default rules uses the following rules:

Recent time stamp of the record. The consolidation process skips the rule when you persist the consolidated data in HDFS or when you run the consolidation job in the initial mode.
Highest value of the combined primary key and source column values. The consolidation process uses case-insensitive lexicographical ordering to find the highest value.

For example, if a column rule returns multiple values and you do not define any default rules, the consolidation process uses the system-defined default rules. The rules identify the record that has the recent time stamp and then select the corresponding column value as the preferred column value. If you have multiple records with the same time stamp, the rules combine the primary key and source column values of each record and select the record that has the highest value. The rules then return the corresponding column value as the preferred column value.