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`@@ -21,6 +21,8 @@ include::high-performance-index.adoc[]`
`21`	`21`
`22`	`22`	`include::query-optimization.adoc[]`
`23`	`23`
	`24`	`+include::locks.adoc[]`
	`25`	`+`
`24`	`26`	`include::sharding.adoc[]`
`25`	`27`
`26`	`28`	`include::explain-in-detail.adoc[]`

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	`1`	`+[#locks]`
	`2`	`+== 锁`
	`3`	`+`
	`4`	`+* 共享锁 Shared Lock,简称 S 锁`
	`5`	`+* 独占锁 Exclusive Lock,也称排他锁,简称 X 锁`
	`6`	`+* 意向共享锁 Intention Shared Lock,简称 IS 锁。当事务准备在某条记录上加 S 锁时,需要先在表级别加一个 IS 锁。`
	`7`	`+* 意向独占锁 Intention Exclusive Lock,简称 IX 锁。当事务准备在某条记录上加 X 锁时,需要先在表级别加一个 IX 锁。`
	`8`	`+`
	`9`	`+NOTE: 意向共享锁和意向独占锁并不是真正的锁,而是相当于一个公告牌。表示有记录被锁定了。避免在锁表(对表加共享锁或独占锁时去遍历全部记录。)`

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`@@ -37,8 +37,7 @@ Repeatable Read(可重复读) 是 MySQL 默认事务隔离级别。`
`37`	`37`	`. 不可重复读 NonRepeatable Read -- 如果一个事务修改了另外一个未提交事务读取的数据,就意味着发生了不可重复读现象,或者叫模糊读 Fuzzy Read 现象。可以把不可重复读现象简称为 P2。`
`38`	`38`	`. 幻读 Phantom -- 如果一个事务先根据某些搜索条件查询出一些记录,在该事务未提交时,另一个事务写入了一些符合那些搜索条件的记录(CUD 任意一种),就意味着发生了幻读现象。可以把幻读现象简称为 P3。`
`39`	`39`
`40`		`-TIP: 这里采用 https://www.microsoft.com/en-us/research/wp-content/uploads/2016/02/tr-95-51.pdf[《A Critique of ANSI SQL Isolation Levels》^] 论文中的定义。`
`41`		`-`
	`40`	`+TIP: 这里采用 https://arxiv.org/abs/cs/0701157[《A Critique of ANSI SQL Isolation Levels》^] 论文中的定义。`
`42`	`41`
`43`	`42`
`44`	`43`	`==== Phantom Read(幻读)`

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