values list from a set of records in response to a user 39 s request more specifically the extrema values system 118 reads all of the records and creates the extrema values list by only sorting a portion of the read records the extrema values system 118 sorts these records in either a descending or an ascending order based on a user 39 s request the user 39 s request may also include a grouping expression that causes the extrema values system 118 to group the records according to the values in the fields specified by the grouping expression when a grouping expression exists the extrema values system 118 creates one or more extrema values lists with each list focusing on a particular group the extrema values system 118 stores the grouping expressions in the cache of each processing unit in absence of a grouping expression the extrema values system 118 only creates one list to create the extrema values list s the extrema values system 118 reads each record in the set of records during the reading process before all of the records have been read the extrema values list is referred to as a candidate extrema values list and the elements on the extrema values list are referred to as candidate extrema values the list and the elements.