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数据缓存实验

set  autotrace traceonly/off; --打开/关闭 跟踪模式，执行计划+statistics

select * from hr.jobs;

alter system flush buffer_cache; ----清除缓存，数据库数据高速缓存

select * from hr.jobs;

select * from hr.jobs;

set autotrace off;

---

9 consistent gets         读取的block数量

6 physical reads      优化时，物理读越少越好

show sga;

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存储文件实验：

NOMOUNT

MOU