| 摘要 |
This disclosure addresses the need for pre-caching of database query results which in general is the caching of the results of query evaluation before they are needed. In certain embodiments of query evaluation, the computing time required to evaluate a query is dominated by the reverse query, the evaluation of which determines the available remaining selectors and the number of items associated with each. The time to compute this reverse query is on average approximately proportional to the number of matching items. This result is used as a very convenient method of determining, before evaluation, which conjunctive queries will take the most time to evaluate—the long queries. These long queries can then be pre-cached, making them available for faster responses when they are needed. Methods of using cached conjunctive query results to more quickly evaluate certain queries comprising the disjunctive Boolean operators are also described. |
