The 2 nd layer also called the brain of Mysql. Deal with parsing ,analysis,optimization,caching, and built-in the functions
The 2 nd layer also called the brain of Mysql. Deal with parsing ,analysis,optimization,caching, and built-in the functions
Security socket layer
Granularity : 粒度
Dirty read 只能够读到已经提交的数据,但是不能保证另外一个事务中,相同两次读取结果一致 保证结果一致,但是你选了几行之后,如果别人在这几行中间插入数据,那么你选的就变了 SERIALIZABLE 保证了你选的那个序列, SERIALIZABLE places a lock on every row it reads. 非常少用
DDL : Data Definition Language
MVCC to achieve high concurrency, InnoDB can store each table’s data and indexes in separate files. InnoDB can also use raw disk partitions for building its tablespace.