《Mysql學習MySQL中開啟和使用通用查詢日志的實例教程》要點：
本文介紹了Mysql學習MySQL中開啟和使用通用查詢日志的實例教程，希望對您有用。如果有疑問，可以聯系我們。
MYSQL必讀開啟通用查詢日志
因為為了性能考慮,一般通用查詢日志general log不會開啟.slow log可以定位一些有性能問題的sql,而general log會記錄所有的SQL.
MYSQL必讀mysql5.0版本,如果要開啟slow log、general log,需要重啟,從MySQL5.1.6版開始,general query log和slow query log開始支持寫到文件或者數據庫表兩種方式,并且日志的開啟,輸出方式的修改,都可以在Global級別動態修改.
MYSQL必讀
mysql>select version();
MYSQL必讀
+――――+
| version() |
+――――+
| 5.1.37-log |
+――――+
1 row in set (0.02 sec)
MYSQL必讀設置日志輸出方式為文件(如果設置log_output=table的話,則日志結果會記錄到名為gengera_log的表中,這表的默認引擎都是CSV)：
MYSQL必讀
mysql>set global log_output=file;
MYSQL必讀
Query OK, 0 rows affected (0.00 sec)
MYSQL必讀設置general log的日志文件路徑：
MYSQL必讀
mysql>set global general_log_file='/tmp/general.log';
MYSQL必讀
Query OK, 0 rows affected (0.00 sec)
MYSQL必讀?開啟general log：
MYSQL必讀
mysql>set global general_log=on;
MYSQL必讀
Query OK, 0 rows affected (0.02 sec)
MYSQL必讀過一段時間后,關閉general log：
MYSQL必讀
mysql>set global general_log=off;
MYSQL必讀
Query OK, 0 rows affected (0.02 sec)
MYSQL必讀通用查詢日志的系統變量
MYSQL必讀
log_output=[none|file|table|file,table] #通用查詢日志輸出格式
MYSQL必讀
general_log=[on|off] #是否啟用通用查詢日志
general_log_file[=filename] #通用查詢日志位置及名字
MYSQL必讀通用查詢日志的備份
MYSQL必讀在Linux或Unix中,你可以通過下面的命令重新命名文件
MYSQL必讀并創建一個新文件：
MYSQL必讀
shell> mv hostname.log hostname-old.log
shell> mysqladmin flush-logs
shell> cp hostname-old.log to-backup-directory
shell> rm hostname-old.log
MYSQL必讀在Windows中,服務器打開日志文件期間不能重新命名日志文件.必須先停止服務器然后重新命名日志文件.然后重啟服務器來創建新日志文件.
MYSQL必讀演示通用查詢日志的使用
MYSQL必讀a、啟用通用查詢日志
MYSQL必讀
--演示環境
root@localhost[(none)]> show variables like '%version%';
MYSQL必讀
+-------------------------+------------------------------+
| Variable_name | Value |
+-------------------------+------------------------------+
| innodb_version | 5.5.39 |
| protocol_version | 10 |
| slave_type_conversions | |
| version | 5.5.39-log |
| version_comment | MySQL Community Server (GPL) |
| version_compile_machine | x86_64 |
| version_compile_os | Linux |
+-------------------------+------------------------------+
MYSQL必讀
--查看系統變量
root@localhost[(none)]> show variables like '%general%';
MYSQL必讀
+------------------+----------------------------+
| Variable_name | Value |
+------------------+----------------------------+
| general_log | OFF |
| general_log_file | /var/lib/mysql/suse11b.log |
+------------------+----------------------------+
MYSQL必讀
--查看當前的通用日志,顯示無日志文件
root@localhost[(none)]> system ls /var/lib/mysql/suse11b.log
MYSQL必讀
ls: cannot access /var/lib/mysql/suse11b.log: No such file or directory
MYSQL必讀
--設置變量general_log以開啟通用查詢日志
root@localhost[(none)]> set @@global.general_log=1;
MYSQL必讀
Query OK, 0 rows affected (0.00 sec)
MYSQL必讀
--再次查看通用日志文件已存在
root@localhost[(none)]> system ls /var/lib/mysql/suse11b.log
/var/lib/mysql/suse11b.log
root@localhost[(none)]> select * from tempdb.tb1; --執行查詢
MYSQL必讀
+------+------+
| id | val |
+------+------+
| 1 | jack |
+------+------+
MYSQL必讀
--查看通用日志文件內容
root@localhost[(none)]> system more /var/lib/mysql/suse11b.log
/usr/sbin/mysqld, Version: 5.5.39-log (MySQL Community Server (GPL)). started with:
MYSQL必讀
Tcp port: 3306 Unix socket: /var/lib/mysql/mysql.sock
Time Id Command Argument
141003 16:18:12 4 Query show variables like '%general%'
141003 16:18:55 4 Query select * from tempdb.tb1
MYSQL必讀
b、更改通用查詢日志位置
MYSQL必讀
root@localhost[(none)]> exit
MYSQL必讀
Bye
suse11b:~ # service mysql stop
Shutting down MySQL... done
suse11b:~ # mysqld --general_log_file=/tmp/suse11b.log --user=mysql &
[1] 47009
suse11b:~ # ps -ef|grep mysql|grep -v grep
mysql 47009 44514 1 16:22 pts/0 00:00:00 mysqld --general_log_file=/tmp/suse11b.log --user=mysql
root 47053 44514 0 16:22 pts/0 00:00:00 grep mysql
suse11b:~ # mysql
MYSQL必讀
root@localhost[(none)]> system ls /tmp/suse11b.log
MYSQL必讀
ls: cannot access /tmp/suse11b.log: No such file or directory
MYSQL必讀
root@localhost[(none)]> show variables like '%gener%';
MYSQL必讀
+------------------+------------------+
| Variable_name | Value |
+------------------+------------------+
| general_log | OFF |
| general_log_file | /tmp/suse11b.log |
+------------------+------------------+
MYSQL必讀
root@localhost[(none)]> set global general_log=on;
MYSQL必讀
Query OK, 0 rows affected (0.01 sec)
MYSQL必讀
--此時從系統變量看出,通用日志已經到/tmp目錄下
root@localhost[(none)]> show variables like '%gener%';
MYSQL必讀
+------------------+------------------+
| Variable_name | Value |
+------------------+------------------+
| general_log | ON |
| general_log_file | /tmp/suse11b.log |
+------------------+------------------+
MYSQL必讀
--發布查詢
root@localhost[(none)]> select count(*) from tempdb.tb1;
MYSQL必讀
+----------+
| count(*) |
+----------+
| 1 |
+----------+
MYSQL必讀
--查看通用日志文件內容
root@localhost[(none)]> system more /tmp/suse11b.log
MYSQL必讀
mysqld, Version: 5.5.39-log (MySQL Community Server (GPL)). started with:
Tcp port: 3306 Unix socket: /var/lib/mysql/mysql.sock
Time Id Command Argument
141003 16:30:03 1 Query show variables like '%gener%'
141003 16:30:09 1 Query select count(*) from tempdb.tb1
MYSQL必讀
c、通用查詢日志輸出方式
MYSQL必讀
--可以輸出為文件,表以及不輸出,即TABLE,FILE,NONE
--系統變量log_output
root@localhost[(none)]> show variables like 'log_output';
MYSQL必讀
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| log_output | FILE |
+---------------+-------+
MYSQL必讀
--下面修改為輸出為表方式
root@localhost[(none)]> set global log_output='TABLE';
MYSQL必讀
Query OK, 0 rows affected (0.00 sec)
MYSQL必讀
root@localhost[(none)]> show variables like 'log_output';
MYSQL必讀
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| log_output | TABLE |
+---------------+-------+
MYSQL必讀
--發布查詢
root@localhost[(none)]> select * from tempdb.tb1;
MYSQL必讀
+------+------+
| id | val |
+------+------+
| 1 | jack |
+------+------+
MYSQL必讀
root@localhost[(none)]> system more /tmp/suse11b.log
MYSQL必讀
mysqld, Version: 5.5.39-log (MySQL Community Server (GPL)). started with:
Tcp port: 3306 Unix socket: /var/lib/mysql/mysql.sock
Time Id Command Argument
141003 16:30:03 1 Query show variables like '%gener%'
141003 16:30:09 1 Query select count(*) from tempdb.tb1
141003 16:31:00 1 Query show variables like 'log_output'
141003 17:00:48 1 Query set global log_output='TABLE' #通用查詢日志輸出到文件僅僅記錄到全局變量的修改
MYSQL必讀
--mysql.general_log記錄了通用查詢日志的信息
root@localhost[(none)]> desc mysql.general_log;
MYSQL必讀
+--------------+------------------+------+-----+-------------------+-----------------------------+
| Field | Type | Null | Key | Default | Extra |
+--------------+------------------+------+-----+-------------------+-----------------------------+
| event_time | timestamp | NO | | CURRENT_TIMESTAMP | on update CURRENT_TIMESTAMP |
| user_host | mediumtext | NO | | NULL | |
| thread_id | int(11) | NO | | NULL | |
| server_id | int(10) unsigned | NO | | NULL | |
| command_type | varchar(64) | NO | | NULL | |
| argument | mediumtext | NO | | NULL | |
+--------------+------------------+------+-----+-------------------+-----------------------------+
MYSQL必讀
--從通用查詢日志表里查看通用查詢日志的內容
root@localhost[(none)]> select thread_id,command_type,argument from mysql.general_log;
MYSQL必讀
+-----------+--------------+---------------------------------------------------------------+
| thread_id | command_type | argument |
+-----------+--------------+---------------------------------------------------------------+
| 1 | Query | show variables like 'log_output' |
| 1 | Query | select * from tempdb.tb1 |
| 1 | Query | desc mysql.general_log |
| 1 | Query | select thread_id,command_type,argument from mysql.general_log |
+-----------+--------------+---------------------------------------------------------------+
MYSQL必讀
root@localhost[(none)]> show variables like 'log_output';
MYSQL必讀
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| log_output | TABLE |
+---------------+-------+
MYSQL必讀 --使用FILE,TABLE 2者混合輸出通用日志 root@localhost[(none)]> set global log_output='file,table';
MYSQL必讀
Query OK, 0 rows affected (0.00 sec)
MYSQL必讀
root@localhost[(none)]> select @@global.log_output;
MYSQL必讀
+---------------------+
| @@global.log_output |
+---------------------+
| FILE,TABLE |
+---------------------+
MYSQL必讀
root@localhost[(none)]> insert into tempdb.tb1 values(2,'robinson');
MYSQL必讀
Query OK, 1 row affected (0.06 sec)
MYSQL必讀
root@localhost[(none)]> commit;
MYSQL必讀
Query OK, 0 rows affected (0.01 sec)
MYSQL必讀
--驗證結果,表和文件里邊存在通用的日志記錄
root@localhost[(none)]> system tail /tmp/suse11b.log|grep robinson
MYSQL必讀
141003 17:41:54 2 Query insert into tempdb.tb1 values(2,'robinson')
MYSQL必讀
root@localhost[(none)]> select thread_id,command_type,argument from mysql.general_log
-> where argument like '%robinson%';
MYSQL必讀
+-----------+--------------+------------------------------------------------------------------------+
| thread_id | command_type | argument |
+-----------+--------------+------------------------------------------------------------------------+
| 2 | Query | insert into tempdb.tb1 values(2,'robinson') |
| 2 | Query | select thread_id,command_type,argument from mysql.general_log |
| | | where argument like ''robinson'' |
+-----------+--------------+------------------------------------------------------------------------+
MYSQL必讀
d、關閉通用查詢日志
MYSQL必讀 --可以通過設置系統變量general_log來關閉通用查詢日志,此時日志輸出設置為FILE,TABLE
root@localhost[(none)]> show variables like 'log_output';
MYSQL必讀
+---------------+------------+
| Variable_name | Value |
+---------------+------------+
| log_output | FILE,TABLE |
+---------------+------------+
MYSQL必讀
root@localhost[(none)]> set global general_log=off;
MYSQL必讀
Query OK, 0 rows affected (0.01 sec)
MYSQL必讀
root@localhost[(none)]> show variables like '%gener%';
MYSQL必讀
+------------------+------------------+
| Variable_name | Value |
+------------------+------------------+
| general_log | OFF |
| general_log_file | /tmp/suse11b.log |
+------------------+------------------+
MYSQL必讀
root@localhost[(none)]> delete from tempdb.tb1 where id=2;
MYSQL必讀
Query OK, 1 row affected (0.12 sec)
MYSQL必讀
root@localhost[(none)]> commit;
MYSQL必讀
Query OK, 0 rows affected (0.00 sec)
MYSQL必讀
root@localhost[(none)]> system tail -n 1 /tmp/suse11b.log
MYSQL必讀
141003 17:45:13 2 Query set global general_log=off
MYSQL必讀
root@localhost[(none)]> select thread_id,command_type,argument from mysql.general_log
-> where argument like '%delete%';
MYSQL必讀 Empty set (0.00 sec)MYSQL必讀--從上面的演示可知,盡管我們設置了log_output為FILE,TABLE,但general_log為OFF,通用日志無任何記錄產生
MYSQL必讀
root@localhost[(none)]> set global log_output=none;
MYSQL必讀
Query OK, 0 rows affected (0.00 sec)
MYSQL必讀
root@localhost[(none)]> set global general_log=1;
MYSQL必讀
Query OK, 0 rows affected (0.00 sec)
MYSQL必讀
root@localhost[(none)]> truncate table tempdb.tb1;
MYSQL必讀
Query OK, 0 rows affected (0.01 sec)
MYSQL必讀
root@localhost[(none)]> system tail -n 1 /tmp/suse11b.log
MYSQL必讀
Time Id Command Argument
--通過上面的演示,在log_output=none,general_log=on的清下下無任何通用日志輸出.
MYSQL必讀?
