MySQL查找SQL耗时瓶颈 SHOW profiles

1、首先查看是否开启profiling功能

SHOW VARIABLES LIKE '%pro%';

或者

SELECT @@profiling;

2、开启profiling

SET profiling=1;

3、执行sql语句

例如：

SELECT   table_schema AS 'Db Name',  ROUND( SUM( data_length + index_length ) / 1024 / 1024, 3 ) AS 'Db Size (MB)',  ROUND( SUM( data_free ) / 1024 / 1024, 3 ) AS 'Free Space (MB)'FROM information_schema.tablesGROUP BY table_schema ;

4、查看结果

SHOW profiles;

SHOW profile ALL FOR QUERY 94;

94是查询ID号。

SHOW profiles语法：

SHOW PROFILE [type [, type] … ]    [FOR QUERY n]    [LIMIT row_count [OFFSET offset]]type:    ALL  | BLOCK IO  | CONTEXT SWITCHES  | CPU  | IPC  | MEMORY  | PAGE FAULTS  | SOURCE  | SWAPS