A mechanism is provided for determining distinct values of an attribute in a data table including the attribute and data records stored in a set of data blocks. Attribute value information is provided for each data block that comprises information indicating distinct values of the attribute in the data blocks. At least part of a current data block of the data table is scanned to determine current distinct values of the attribute. The current distinct values of the attribute of the current data block are added to a list of current distinct values of the data table. The scanning and adding are repeatedly performed for a further data block of the data table if the attribute value information of the further data block indicates at least one distinct value that is not present in the list. The list of current distinct values are then provided.