基于退火遗传算法的多连接查询优化应用研究

Research on Multi-join Query Optimization Based on Annealing-genetic Algorithm

阐述了引入模拟退火机制的遗传算法求解数据库多连接查询优化问题的设计过程。给出了基于左深树策略空间的染色体编码方案,采用自适应交叉、变异概率的方法对个体适应度函数值进行优化调整,解决了固定遗传算子生成新个体方面的不足,提升了算法的收敛效率。仿真实验结果表明,应用组合退火遗传算法对数据库多连接查询优化可获得满意的优化效果。

This paper elaborates on design of the genetic algorithm with simulated annealing mechanism for the optimization of multi-join query.It provides a chromosome coding scheme.Moreover,the methods of variable crossover probability and mutation probability are adopted to optimize individual fitness value.The problem of generating a new individual by fixed genetic operators is solved,and the astringency of the algorithm is improved.The simulation results verify the effectiveness of the method.