MySQL Database performance Chapter

Slow query: SQL statements that exceed the set time are recorded in the specified file

1. Watch MySQL Slow query default time (default 10 seconds)

Show variables like ' long% ';

2, modify the slow query set time

Set long_query_time=1;

3. Check if MySQL turns on automatic recording (default off)

Show variables like ' slow% ';

4. Turn on MySQL automatic recording function

Set global slow_query_log=on;

Show variables like ' slow% ';

5. Specify the SQL statement to save the path

Set global slow_query_log_file= ' C:\\log.txt ';

Show variables like ' slow% ';

To view the SQL statement execution time

1, check whether to open the SQL statement query time

Show variables like ' profiling% ';

2. Turn on MySQL Statistics SQL statement execution time

Set Profiling=on;

Show variables like ' profiling% '

3. Execute SQL statements

Select Kch from KCB where kcm= ' database ' or kcm= ' QTP ';

4. View execution Time

Show Profiles;

MySQL Database performance Chapter