`

待整理2018-01-28

 
阅读更多

4.
long double 32位,分高低位存放,非原子性操作,其他基本数据类型是原子性

基本数据类型的线程安全



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@JrdLoginCheck
注解使用方式
通过AOP获取接口是否带有该注解

PCSecurityInterceptor


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SELECT COUNT(0)
FROM p2p_td_project
WHERE 1 = 1
AND C_STATUS IN ('301')
ORDER BY C_STATUS + 0 ASC, CASE
WHEN C_STATUS = 110 THEN C_LOAN_BEGIN_DATE
END ASC, CASE
WHEN C_STATUS = 201 THEN C_CREATE_TIME
END DESC, CASE
WHEN C_STATUS = 209 THEN C_LOAN_ACTUAL_END_DATE
END DESC, CASE
WHEN C_STATUS = 301 THEN C_TRANSFER_DATE
END DESC ;
-- 未使用到索引?
-- 组合索引,最左匹配,为何索引使用到 C_STATUS ?

explain SELECT COUNT(0)
FROM p2p_td_project
WHERE 1 = 1
AND C_STATUS IN ('301');
C_STATUS 为组合索引的右侧,理论上使用不到索引,但此处有用到
key_len 为组合索引的长度
原理:覆盖索引:
https://www.cnblogs.com/chenpingzhao/p/4776981.html
http://blog.csdn.net/garfielder007/article/details/54295577
Explain 使用解读
http://blog.csdn.net/xifeijian/article/details/19773795

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