mysql查找sql耗时瓶颈 show profiles

SHOW VARIABLES LIKE ‘%pro%‘; 

SELECT @@profiling; 

SET profiling=1; 

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.tables  
GROUP BY table_schema ;  

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