mysql 分区 + 脏读

ALTER TABLE user_2  PARTITION  BY  RANGE (YEAR(createTime))

( 

PARTITION p1 VALUES LESS THAN (2017),

-- PARTITION user_2017 VALUES LESS THAN (2017),

-- PARTITION user_2016 VALUES LESS THAN (2016),

-- PARTITION user_2015 VALUES LESS THAN (2015),

-- PARTITION user_2014 VALUES LESS THAN (2014),

PARTITION p11 VALUES LESS THAN MAXVALUE

);

-- 查询分区情况

select

  partition_name part, 

  partition_expression expr, 

  partition_description descr, 

  table_rows 

from information_schema.partitions  where

  table_schema = schema() 

  and table_name='user_2'

-- 分区

-- 最大分区 1024

-- 建立分区：去掉外键索引，唯一索引，full-text全文检索索引，建立 createTime主键索引

-- SELECT YEAR(createTime) FROM user_2

EXPLAIN SELECT count(*) from user_2 where createTime >= '2017'

EXPLAIN SELECT count(*) from user where createTime >= '2017'

给分区分配不同的物理磁盘

https://m.aliyun.com/yunqi/ziliao/59904

脏读，是一种隔离级别，with（nolock），读取数据不加锁，spring tx 可以传 uncommit来获取脏读数据，innodb 设置并发数 128线程

http://blog.itpub.net/15498/viewspace-2141352/