Backup Mechanism of Schema Mapping in Peer-to-peer Data Management System
Zheng Zhao · Jisuanji gongcheng · 2009
To address the problem of frequently broken mapping paths caused by peer dynamically departing and returning the network due to their autonomous nature in PDMS, an absent peer bypassing method is proposed based on schema mapping backup mechanism, which provides tree-structure organized mapping information to the downstream peers. When a peer departs in the mapping path, queries of its downstream peers rely on the mapping information and the backup upstream mappings to bypass the absent peer. Simulation and analysis result shows that the in mapping backup mechanism increases the query achievability, so that results can be returned from more local databases.