Ch02-数据库理论 之 RBO
October 10, 2021
Rule-Based Optimization 基于规则的优化器
| RBO 规则 | 说明 |
|---|---|
| 谓词重写 | LIKE 规则，BETWEEN-AND 规则，IN 转 OR 规则，IN 转 ANY 规则，OR 转 ANY 规则，ALL/ANY 转聚合，NOT 规则，OR 转 UNION 规则 |
| 谓词预处理 | 1 < a => a > 1 , 10 != id => id != 10 |
| 谓词下推 | t1.id = 1 t1 left join t2 on t1.id = t2.id => t1 left join t2 on t1.id = t2.id and t1.id = 1 |
| 列裁剪优化 | |
| 常量传递 | |
| 表达式计算 |