SPARQL (SPARQL Protocol and RDF Query Language) query optimization method for column family overlay storage

The invention discloses a SPARQL (SPARQL Protocol and RDF Query Language) query optimization method for column family overlay storage. When query is star query, a connection first execution strategy is used, and query optimization is the union of column family projection; when the query is chain query, cost estimation is carried out to judge whether the connection first execution strategy or a combination first execution strategy has smallest cost, the execution strategy with the smallest cost is selected from the execution strategies, and query efficiency is obviously improved. 本发明公开了种列族覆盖存储的SPARQL查询优化方法，当为星型查询时，使用连接优先的执行策略，查询优化为列族投影的包并；当为链型查询时，通过代价预估，判断连接优先与包并优先哪种执行策略代价最小，从中选择代价最小的执行策略，可使查询效率显著提升。