基于遗传算法的关系数据库查询优化策略

The database query optimization strategies based on genetic algorithms

介绍基本遗传算法的基本思想和工作流程,针对数据库管理系统中最难处理和优化的连接操作,讨论在左深连接树的计划集合和浓密连接树的计划集合上的基于遗传算法的查询优化策略。同时通过具体的查询实例说明其左深度连接树和浓密连接树的染色体编码方法,并基于该编码方式进一步确定了基本遗传算法中其它的七个变元。

The basic ideas and working flows of genetic algorithms are outlined. For the join operator that is the most difficult to process and optimize in DBMS,the query optimization strategies, based on genetic algorithms, over the plan collections of left-deep join tree and the plan collections of bushy join tree are discussed. The methods of chromosome coding on left-deep join tree and bushy join tree are showed by query instances, and further other seven parameters of basic genetic algorithms are determined by the design of coding.