Patent ID: 8335782
Filing Date: 2012-12-18
Classification: G06F

Abstract:
1. A ranking query processing method for stream data that receives stream data as a plurality of continually arriving stream tuples to which timestamps are attached and continually executes query processing on the stream data based on a pre-registered query, the method comprising: determining a lifetime, in a window, of each arriving stream tuple in response to arrival of the stream tuple, and determining an end of a lifetime, in the window, of each previously arrived stream tuple in addition thereto according to a window designation by the query; generating window differential information indicating insertion of a stream tuple into the window and deletion of a stream tuple from the window at each time; using the window differential information and archived information to compute a ranking, in the window, concerning an ordered target item between stream tuples that are within the window including stream tuples for which the ranking is outside of an output designation range designated by the query each time a lifetime of a stream tuple starts and each time a lifetime of a stream tuple ends according to ranking processing by the query, and updating a ranking information that indicates the ranking according to the computed ranking; outputting a stream tuple set of stored stream tuples for which the raking is included in the output designation range designated by the query; storing the updated ranking information of the stream tuples that are within the window and are present within a lifetime in the window for which the ranking is outside of the output designation range in a ranking information holding buffer that archives the ranking information; and storing the stream tuples that are within the window and includes tuples for which the ranking is outside of the output designation range.