mysql数据库卡顿问题排查过程

SELECT * FROM information_schema.INNODB_TRX

SHOW PROCESSLIST

KILL 123

-- 据库大小和索引大小
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;

-- 查询单个库中所有表磁盘占用大小
SELECT CONCAT(TRUNCATE(SUM(data_length)/1024/1024,2),'MB') AS data_size,
         CONCAT(TRUNCATE(SUM(max_data_length)/1024/1024,2),'MB') AS max_data_size,
         CONCAT(TRUNCATE(SUM(data_free)/1024/1024,2),'MB') AS data_free,
         CONCAT(TRUNCATE(SUM(index_length)/1024/1024,2),'MB') AS index_size
  FROM information_schema.tables
WHERE TABLE_SCHEMA = '你的数据库名';

-- 查看数据库中所有表的信息
SELECT
    CONCAT( table_schema, '.', table_name ) AS 'Table Name',
    table_rows AS 'Number of Rows',
    CONCAT( ROUND( data_length / ( 1024 * 1024 * 1024 ), 6 ), ' G' ) AS 'Data Size',
    CONCAT( ROUND( index_length / ( 1024 * 1024 * 1024 ), 6 ), ' G' ) AS 'Index Size',
    CONCAT( ROUND( ( data_length + index_length ) / ( 1024 * 1024 * 1024 ), 6 ), ' G' ) AS 'Total' 
FROM
    information_schema.TABLES W 
WHERE
    table_schema LIKE '你的数据库名';
    
    ```
    ## 4、单位GB表空间
  ```sql
    # 单位GB表空间
SELECT CONCAT( ROUND( SUM( data_length ) / ( 1024 * 1024 * 1024 ), 6 ), 'GB' ) AS 'Total Data Size' 
FROM information_schema.TABLES 
WHERE table_schema LIKE '你的数据库名';

 -- 索引空间
SELECT CONCAT( ROUND( SUM( index_length ) / ( 1024 * 1024 * 1024 ), 6 ), ' GB' ) AS 'Total Index Size' 
FROM information_schema.TABLES 
WHERE table_schema LIKE '你的数据库名'; 

SHOW VARIABLES LIKE '%connect%';

 service mysql start
 service mysql stop
 service mysql restart