[MySQL learning notes 21] storage engine

Query storage engine

utilize select create table xxx; View the table creation statement , You can see what engine is used

Specify the storage engine

create table xxx(…) engine=INNODB;

View the list of storage engines

show engines;

innodb engine

Introduce

innodb It is an engine with both reliability and performance , And now mysql The default engine for

characteristic

1.DML Statement support ACID Model , Support transactions
2. Row-level locks
3. Support for foreign key constraints

File format

.idb
Storage table structure (frm、sdi)、 Data and index
Parameters ：innodb_file_per_table Used to specify whether each table corresponds to a idb file

Logical storage structure

MyISAM engine

Introduce

mysql Early default engine

characteristic

1. Unsupported transaction
2. Foreign key not supported
3. Table locks
4. Fast access

File store

.sdi Storage table structure
.myi Storage index
.myd Store the data

Memory engine

Introduce

Memory The table data of the engine is stored in memory , Not in documents

characteristic

1. Memory storage
2.hash Indexes
3. Table locks

File store

.sdi Storage table structure
The rest of the data is stored in memory

Comparison of three engines