统计 MySQL 数据库占用的空间

mysql  Ver 8.4.1 for Linux on x86_64 (MySQL Community Server - GPL)
mysql> 
select TABLE_SCHEMA, concat(truncate(sum(data_length)/1024/1024,2),' MB') as data_size, concat(truncate(sum(index_length)/1024/1024,2),'MB') as index_size from information_schema.tables group by TABLE_SCHEMA ORDER BY data_size desc;
+--------------------+-----------+------------+
| TABLE_SCHEMA       | data_size | index_size |
+--------------------+-----------+------------+
| mysql              | 7.51 MB   | 0.34MB     |
| test_db            | 230.31 MB | 30.31MB    |
| sys                | 0.01 MB   | 0.00MB     |
| information_schema | 0.00 MB   | 0.00MB     |
| performance_schema | 0.00 MB   | 0.00MB     |
+--------------------+-----------+------------+
5 rows in set (0.17 sec)

查看 MYSQL 的版本

mysql> 
status;
--------------
mysql  Ver 8.4.1 for Linux on x86_64 (MySQL Community Server - GPL)

Connection id:		26
Current database:	
Current user:		root@localhost
SSL:			Not in use
Current pager:		stdout
Using outfile:		''
Using delimiter:	;
Server version:		8.4.1 MySQL Community Server - GPL
Protocol version:	10
Connection:		Localhost via UNIX socket
Server characterset:	utf8mb4
Db     characterset:	utf8mb4
Client characterset:	latin1
Conn.  characterset:	latin1
UNIX socket:		/var/run/mysqld/mysqld.sock
Binary data as:		Hexadecimal
Uptime:			19 hours 36 min 40 sec

Threads: 3  Questions: 661  Slow queries: 4  Opens: 737  Flush tables: 3  Open tables: 150  Queries per second avg: 0.009
--------------

启用 MYSQL 慢日志

官方文档: https://dev.mysql.com/doc/refman/8.4/en/slow-query-log.html

[mysqld]
slow_query_log=ON
long_query_time=10

查看当前运行中的慢日志设置

mysql> 
show variables like 'slow_query%';
+---------------------+--------------------------------------+
| Variable_name       | Value                                |
+---------------------+--------------------------------------+
| slow_query_log      | OFF                                  |
| slow_query_log_file | /var/lib/mysql/mysql-master-slow.log |
+---------------------+--------------------------------------+
2 rows in set (0.01 sec)

mysql> 
show variables like 'long_query_time';
+-----------------+-----------+
| Variable_name   | Value     |
+-----------------+-----------+
| long_query_time | 10.000000 |
+-----------------+-----------+
1 row in set (0.01 sec)

基于Mysql的文档记录:

To include slow administrative statements in the slow query log, enable the log_slow_admin_statements system variable. Administrative statements include ALTER TABLE, ANALYZE TABLE, CHECK TABLE, CREATE INDEX, DROP INDEX, OPTIMIZE TABLE, and REPAIR TABLE.

查看 Binlog 的内容

mysql> 
show binlog events in 'binlog.000005';
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