Matching method of symmetrical issuing subscription system based on plural one-dimensional index

Abstract

The invention discloses a matching method of a symmetrical issuing subscription system based on a plural one-dimensional index, belonging to the field of databases and comprising the following steps of: receiving data submitted by a user through a system; inquiring the subscription matched with an event and inserting the event into an event index; and inquiring the event matched with the subscription and inserting the subscription into a subscription index. The method has the advantages that: (1) when the event is matched with the subscription, the inquiring mode of the invention is range query instead of point query; and (2) when a subscription predication index is established, equal predications are stored into a form of B and tree, are considered as the conjunction of unequal predications and are decomposed into greater and smaller predications; and when the index is established, the node is respectively inserted into a greater predication index tree and a smaller predication index tree and two predications are used as a counting condition. Therefore, the data structure of the system is simple and easier to realize. The matching performance and the dynamic maintenance performance of the invention have favorable stability and favorable expansibility.

Description

technical field [0001] The invention belongs to the field of databases, in particular to a matching method for a symmetrical publish-subscribe system based on complex single-dimensional indexes. Background technique [0002] The publish-subscribe system is an application service platform centered on personalized information release and acquisition, such as a service platform that provides release and subscription of information such as stocks, traffic, weather, and news. The information provided by the publisher to the platform is called an event. The filter conditions for interested messages provided by subscribers to the platform are called subscriptions. In traditional publish-subscribe systems, information publishers have no constraints on information subscribers; there is a type of information publishing and acquisition service platforms such as: job seekers, rental For rent-seeking, online barter, etc., the publisher of information needs to filter the recipients of the...

AI Technical Summary

Problems solved by technology

[0004] In terms of matching efficiency, index dynamic maintenance rows, and sensitivity to data distribution, the above matching methods have different characteristics: 1) Methods based on complex single-dimensional indexes, such as the Counting method, have good scalability and dynamic maintainability, It is not sensitive to data distribution. For the filtering of each event, each dimension corresponds to an attribute. The pre-selected result set on each attribute is the entire subscription set, not its subset. The calculation is large and the implementation is more complicated; 2) The method based on high-dimensional index, such as RTree index, is simple to implement. With the deepening of each step of search, the candidate result set is constantly decreasing. The calculation amount is not like the complex single-dimensional index that grows with the number of dimensions. Linear growth requires less calculation, but the maintenance cost of high-dimensional spatial index is high. When the dimension is high, the query operation needs to scan the entire index, and the dynamic maintenance query, its performance is sensitive to data distribution; 3) Based on decision tree The method matching speed is fast, but its dynamic maintenance is very high and it is not usable

[0005] To sum up, in a traditional publish-subscribe system, the publisher is the producer of information, and the subscriber is the consumer of the message. In the symmetric publish-subscribe system, the publisher of the message also hopes to impose constraints, so as to achieve Although the high-dimensional index-based matching method supports the matching of symmetric publish-subscribe events and subscriptions, due to poor dynamic maintenance and its performance is sensitive to data distribution, there are great limitations in usability in practice The method based on complex single-dimensional index does not directly support the matching of symmetric publish-subscribe events and subscriptions, because in traditional methods, events are represented by dots, and events do point queries on subscriptions. In symmetric publish-subscribe systems, events are With constraints, that is, when the event requires a range query on the subscription, the traditional matching method based on the complex single-dimensional index cannot adapt to the application under this condition

Images