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19.1.4.
数据库是事务 ...............................................................
217
原子性(Ato m ic ity ) ...................................................................................................................................217
一致性(C o t s i ste tt cy ) .............................................................................................................................217
隔
离
性(Isolation
)
........................................................................................................................................218
永久性(D u ra b i i ity t ...................................................................................................................................218
1
数据存储过程.特定 功能的
S QL
语句集. ..............................................
218
存储过程优化思路:........................................................................................218
19.1.6................................................................................................................................................................................
触发器(:
一段能自动执行的程
if
)
...............................................................................................................................................218
1
数据.数据库并发策略 ..............................................................
218
19. L71 乐观锁 .....................................................................................218
19. L72 悲观锁 .....................................................................................219
19173
时
间戳 .....................................................................................219
19.18
数据库锁.......................................................................
219
19181 行级锁 ...............................................................................219
19182 表级锁 ...............................................................................219
19.1.81 页级锁 .....................................................................................219
1^.1.9.
基于
Redis
分布式锁..............................................................
219
19工10.
分区分表.....................................................................
220
垂直切分i按照功能模块) .....................................................................................................................................220
水平切分(按照规则划分存储)...........................................................................220
19.1.11.
两阶段提交协
定 ..............................................................................220
19. L111 准备阶段 ........................................................................................221
99. L112 提交阶段 ........................................................................................221
19. L113 缺点 ............................................................................................221
同步阻塞问题...........................................................................................221
单点故障...............................................................................................221
数据不一致(脑裂问题i ........................................................................................................................................221
二阶段无法解决的问题(数据状态不确定i .............................................................................................................221
19.1.12.
三阶段提交协议
...................................................................................................................................222
1911 2 . 1 . C a n C o m mit 阶段 ..........................................................................222
1911 2.2 . P re C o m mit 阶段 .............................................................................222
191123 d o C o m mit 阶段 ................................................................................222
19
丄
1 3
柔性事务
....................................................................................................................................................222
3
. 1 .柔性事务 ....................................................................................222
两阶段型...............................................................................................222
补偿型.................................................................................................222
异步确保型.............................................................................................223
最大努力通知体(多次尝试).............................................................................223
段.
1.14. CAP.............................................................................................................................................................224
一致性(C 1 : ..........................................................................................................................................................224
可用性(A) : ......................................................................................................................................................224
分区容忍性(P): .................................................................................................................................................224
29・ 一致性算法..................................................................................................225
20.1
平.
P-XOS .......................................................................................................................................................225
Paxos 三种角色:P「o p os e i , Acce pto「, Le a m e rs......................................................................................225
Proposer: ........................................................................................................................................................225
Acceptor: ........................................................................................................................................................225
Learner: ..........................................................................................................................................................225
Paxos算法分为两个阶段。具体如下: ........................................................................225
阶段一(准leade「确定): ..............................................................................225
阶段二(leader确认): .....................................................................................................................................225
20.1.2. Zab...........................................................................................................................................................225
1. 崩溃恢复:主要就是Leader选举过程...................................................................226
2. 数据同步:Leader服务器与其他服务器进行数据同步 ....................................................226
3. 消息广播:Leader服务器将数据发送给其他服务器 ......................................................226
20.1.3. Raft ..........................................................................................................................................................226
20.1.3.1. 角色.........................................................................................226
Leader (领导者-日志管理) ............................................................................226
Follower (追随者-日志同步) ..........................................................................226
Candidate (候选者-负责选票) .........................................................................226
201 3.2 . Te rm .任期).................................................................................226