開啟mysql的慢查詢
1.首先要安裝好mysql與客戶端。
2.連線mysql:
mysql -uroot -p123
3.查詢是否開啟了慢查詢：
mysql> show variables like '%slow%';（mysql預設是關閉的）
+---------------------+----------------------------------------+ | Variable_name | Value | +---------------------+----------------------------------------+ | slow_query_log | OFF | | slow_query_log_file| /var/lib/mysql/VM-0-11-ubuntu-slow.log | +---------------------+----------------------------------------+
4.開啟慢查詢：
mysql> set global slow_query_log=1; Query OK, 0 rows affected (0.00 sec)
mysql> show variables like '%slow%'; +---------------------------+----------------------------------------+ | Variable_name | Value | +---------------------------+----------------------------------------+ | log_slow_admin_statements | OFF | | log_slow_slave_statements | OFF | | slow_launch_time | 2 | | slow_query_log | ON | | slow_query_log_file
5.檢視統計的時長：
mysql> show variables like 'long_query_time'; +-----------------+----------+ | Variable_name | Value | +-----------------+----------+ | long_query_time | 10.000000 | +-----------------+----------+ 1 row in set (0.00 sec)
6.修改統計的時長為一秒：
mysql> set global long_query_time=1; Query OK, 0 rows affected (0.00 sec)
mysql> show variables like 'long_query_time'; +-----------------+----------+ | Variable_name | Value | +-----------------+----------+ | long_query_time | 1.000000 | +-----------------+----------+ 1 row in set (0.00 sec) 7.測試是否成功：
執行select sleep(1) as a, 1 as b;
檢視log檔案
mysql> show variables like '%slow%'; +---------------------------+----------------------------------------+ | Variable_name | Value | +---------------------------+----------------------------------------+ | log_slow_admin_statements | OFF | | log_slow_slave_statements | OFF | | slow_launch_time | 2 | | slow_query_log | ON | | slow_query_log_file | /var/lib/mysql/VM-0-11-ubuntu-slow.log | +---------------------------+----------------------------------------+ 5 rows in set (0.00 sec)
vim /var/lib/mysql/VM-0-11-ubuntu-slow.log
# Time: 2018-11-02T08:06:36.206036Z # [email protected]: root[root] @ [124.127.244.29] Id: 100 # Query_time: 1.000249 Lock_time: 0.000000 Rows_sent: 1 Rows_examined: 0 SET timestamp=1541145996; select sleep(1) as a, 1 as b;