MySQL 슬로우 쿼리 로그 설정

MySQL 슬로우 쿼리 로그 설정

MySQL 느린 쿼리 로그 설정

1 방법

vi /etc/my.cnf

[mysqld]
log-slow-queries = 로그파일명
long_query_time = 시간(초)

→ [mysqld] 아래에 2줄을 추가한다.

2 실습

현재 설정 확인

[root@jmnote ~]# cat /etc/my.cnf
[mysqld]
datadir=/var/lib/mysql
socket=/var/lib/mysql/mysql.sock
user=mysql
# Disabling symbolic-links is recommended to prevent assorted security risks
symbolic-links=0
max_allowed_packet=4M

[mysqld_safe]
log-error=/var/log/mysqld.log
pid-file=/var/run/mysqld/mysqld.pid

→ 슬로우 쿼리 설정 없음 확인

로그 폴더 생성

[root@jmnote ~]# mkdir /var/log/mysql
[root@jmnote ~]# chown mysql:mysql /var/log/mysql

[root@jmnote ~]# ll /var/log/ | grep mysql
drwxr-xr-x 2 mysql mysql    4096 Aug  3 22:46 mysql
-rw-r----- 1 mysql mysql   53059 Jun 15 02:08 mysqld.log

로그 설정

[root@jmnote ~]# vi /etc/my.cnf

[mysqld]의 아래 적당한 곳에 다음 내용 기입

long_query_time=3
log-slow-queries=/var/log/mysql/log-slow-queries.log

설정 확인

[root@jmnote ~]# cat /etc/my.cnf
[mysqld]
datadir=/var/lib/mysql
socket=/var/lib/mysql/mysql.sock
user=mysql
# Disabling symbolic-links is recommended to prevent assorted security risks
symbolic-links=0
max_allowed_packet=4M
long_query_time=3
log-slow-queries=/var/log/mysql/log-slow-queries.log

[mysqld_safe]
log-error=/var/log/mysqld.log
pid-file=/var/run/mysqld/mysqld.pid

MySQL 재시작 (설정 적용)

[root@jmnote ~]# service mysqld restart
Stopping mysqld:                                           [  OK  ]
Starting mysqld:                                           [  OK  ]

[root@jmnote ~]# cat /var/log/mysql/log-slow-queries.log
/usr/libexec/mysqld, Version: 5.5.34-log (MySQL Community Server (GPL)). started with:
Tcp port: 0  Unix socket: /var/lib/mysql/mysql.sock
Time                 Id Command    Argument

→ 슬로우 쿼리 로그 파일이 생성되었다.

3 테스트

[root@jmnote ~]# mysql -uroot -pP@ssw0rd -e 'SELECT SLEEP(4)'
+----------+
| SLEEP(4) |
+----------+
|        0 |
+----------+

[root@jmnote ~]# mysql -uroot -pP@ssw0rd -e 'SELECT SLEEP(4)'
+----------+
| SLEEP(4) |
+----------+
|        0 |
+----------+

[root@jmnote ~]# cat /var/log/mysql/log-slow-queries.log
/usr/libexec/mysqld, Version: 5.5.34-log (MySQL Community Server (GPL)). started with:
Tcp port: 0  Unix socket: /var/lib/mysql/mysql.sock
Time                 Id Command    Argument
# Time: 140803 23:19:41
# User@Host: root[root] @ localhost []
# Query_time: 4.001873  Lock_time: 0.000000 Rows_sent: 1  Rows_examined: 0
SET timestamp=1407075581;
SELECT SLEEP(4);
# Time: 140803 23:19:50
# User@Host: root[root] @ localhost []
# Query_time: 4.001939  Lock_time: 0.000000 Rows_sent: 1  Rows_examined: 0
SET timestamp=1407075590;
SELECT SLEEP(4);

4 같이 보기

• /etc/my.cnf

5 참고 자료

• http://faq.hostway.co.kr/Linux_DB/1325