mysql架构和历史

存储引擎

查看：

show table status like 'bigcourse';

结果：

+-----------+--------+---------+------------+------+----------------+-------------+-----------------+--------------+-----------+----------------+---------------------+---------------------+------------+-----------+----------+--------------------+---------+
| Name      | Engine | Version | Row_format | Rows | Avg_row_length | Data_length | Max_data_length | Index_length | Data_free | Auto_increment | Create_time         | Update_time         | Check_time | Collation | Checksum | Create_options     | Comment |
+-----------+--------+---------+------------+------+----------------+-------------+-----------------+--------------+-----------+----------------+---------------------+---------------------+------------+-----------+----------+--------------------+---------+
| bigcourse | InnoDB |      10 | Dynamic    |    2 |           8192 |       16384 |               0 |            0 |         0 |             43 | 2018-06-30 13:46:32 | 2018-07-02 19:32:05 | NULL       | utf8_bin  | NULL     | row_format=DYNAMIC |         |
+-----------+--------+---------+------------+------+----------------+-------------+-----------------+--------------+-----------+----------------+---------------------+---------------------+------------+-----------+----------+--------------------+---------+
1 row in set

字段含义:

Row_format:行的格式。

Data_free:表示已分配但目前没有使用的空间。这部分空间包括了之前删除的行，以及后续可以被INSERT利用到的空间。

MyISAM：不支持事务和行级锁，崩溃后无法安全恢复。

选择哪种搜索引擎

mysql中只有MyISAM支持地理空间搜索。