HASH Index on Non-primary Key Columns of EMS Real-time Database Based on Shared Memory

The real-time database is one of the cores of the energy management system(EMS),on which is based most of the real-time data processing.Introducing the index will greatly optimize the real-time database searching operation to improve its performance.The searching algorithm is described alongside the realization of the HASH index,the HASH index with double overflow areas for "parent-child" type searching is designed and its data structure and search algorithm are treated.It is shown that the HASH index with double overflow areas is a suitable index for "parent-child" type searching with high search efficiency.