视图增量计算的延迟部分补偿算法

The asynchronous propagation algorithms for view increment computing took quite a long time and consumed a lot of computer's system resources, and the result of the partial compensation might be even wrong sometimes. To solve these problems of compensation algorithms, a deferred partial compensation algorithm in data sources was proposed. In this algorithm, the transaction commit timestamp of table changes was kept in data sources, and the latest transaction commit timestamp which was computed for view change was stored. If the table changed between the timestamp which maintained sub-query and the latest transaction commit timestamp, compensation query had to be enforced. Because compensation process referred to the time of single information source, this algorithm avoided the problems of global time and possible errors. Additionally, this algorithm took advantage of the primary and foreign keys to reduce computational cost. Experimental results showed that the proposed algorithm exhibited improvements over the traditional ones.