Techniques are described for executing a query with a top-N clause to select a first N-number of rows in a data source arranged at least according to a first key and a second key of the data source using a first sort order respectively specified for the first key and a second sort order respectively specified for the second key by the query. The data source may include one or more tiles that include at least a portion of the first key and the second key. To execute the query, in an embodiment, a DBMS determines, in a first vector of first key values that are in a first tile, row identifiers identifying entries of the first vector that contain values equal to a tail value that follows a particular top number of the first key values. The DBMS may select, from a second vector of values of the second key in the first tile, second key values identified based on the determined row identifiers of the first vector. In an embodiment, the DBMS generates a result set of the query that includes at least a value from the second key values selected from the second vector based on the determined first row identifiers.