開啟通用查詢?nèi)罩?/strong>
因為為了性能考慮，一般通用查詢?nèi)罩緂eneral 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。
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(shù)據(jù)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(tài)修改。
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mysql>select version(); |
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+————+| version() |+————+| 5.1.37-log |+————+1 row in set (0.02 sec) |
設(shè)置日志輸出方式為文件（如果設(shè)置log_output=table的話，則日志結(jié)果會記錄到名為gengera_log的表中，這表的默認引擎都是CSV）：
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mysql>set global log_output=file; |
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Query OK, 0 rows affected (0.00 sec) |
設(shè)置general log的日志文件路徑：
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mysql>set global general_log_file='/tmp/general.log'; |
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Query OK, 0 rows affected (0.00 sec) |
開啟general log：
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mysql>set global general_log=on; |
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Query OK, 0 rows affected (0.02 sec) |
過一段時間后，關(guān)閉general log：
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mysql>set global general_log=off; |
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Query OK, 0 rows affected (0.02 sec) |
通用查詢?nèi)罩镜南到y(tǒng)變量
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log_output=[none|file|table|file,table] #通用查詢?nèi)罩据敵龈袷?/code> |
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general_log=[on|off] #是否啟用通用查詢?nèi)罩?/code>general_log_file[=filename] #通用查詢?nèi)罩疚恢眉懊?/code> |
通用查詢?nèi)罩镜膫浞?/strong>
在Linux或Unix中，你可以通過下面的命令重新命名文件
并創(chuàng)建一個新文件：
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shell> mv hostname.log hostname-old.logshell> mysqladmin flush-logsshell> cp hostname-old.log to-backup-directoryshell> rm hostname-old.log |
在Windows中，服務(wù)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(wù)器然后重新命名日志文件。然后重啟服務(wù)器來創(chuàng)建新日志文件。
演示通用查詢?nèi)罩镜氖褂?/strong>
a、啟用通用查詢?nèi)罩?/strong>
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--演示環(huán)境root@localhost[(none)]> show variables like '%version%'; |
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+-------------------------+------------------------------+| 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 |+-------------------------+------------------------------+ |
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--查看系統(tǒng)變量root@localhost[(none)]> show variables like '%general%'; |
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+------------------+----------------------------+| Variable_name | Value |+------------------+----------------------------+| general_log | OFF || general_log_file | /var/lib/mysql/suse11b.log |+------------------+----------------------------+ |
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--查看當(dāng)前的通用日志，顯示無日志文件root@localhost[(none)]> system ls /var/lib/mysql/suse11b.log |
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ls: cannot access /var/lib/mysql/suse11b.log: No such file or directory |
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--設(shè)置變量general_log以開啟通用查詢?nèi)罩?/code>root@localhost[(none)]> set @@global.general_log=1; |
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Query OK, 0 rows affected (0.00 sec) |
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--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.logroot@localhost[(none)]> select * from tempdb.tb1; --執(zhí)行查詢 |
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+------+------+| id | val |+------+------+| 1 | jack |+------+------+ |
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--查看通用日志文件內(nèi)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: |
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Tcp port: 3306 Unix socket: /var/lib/mysql/mysql.sockTime Id Command Argument141003 16:18:12 4 Query show variables like '%general%'141003 16:18:55 4 Query select * from tempdb.tb1 |
b、更改通用查詢?nèi)罩疚恢?/strong>
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root@localhost[(none)]> exit |
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Byesuse11b:~ # service mysql stopShutting down MySQL... donesuse11b:~ # mysqld --general_log_file=/tmp/suse11b.log --user=mysql &[1] 47009suse11b:~ # ps -ef|grep mysql|grep -v grepmysql 47009 44514 1 16:22 pts/0 00:00:00 mysqld --general_log_file=/tmp/suse11b.log --user=mysqlroot 47053 44514 0 16:22 pts/0 00:00:00 grep mysqlsuse11b:~ # mysql |
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root@localhost[(none)]> system ls /tmp/suse11b.log |
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ls: cannot access /tmp/suse11b.log: No such file or directory |
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root@localhost[(none)]> show variables like '%gener%'; |
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+------------------+------------------+| Variable_name | Value |+------------------+------------------+| general_log | OFF || general_log_file | /tmp/suse11b.log |+------------------+------------------+ |
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root@localhost[(none)]> set global general_log=on; |
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Query OK, 0 rows affected (0.01 sec) |
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--此時從系統(tǒng)變量看出，通用日志已經(jīng)到/tmp目錄下root@localhost[(none)]> show variables like '%gener%'; |
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+------------------+------------------+| Variable_name | Value |+------------------+------------------+| general_log | ON || general_log_file | /tmp/suse11b.log |+------------------+------------------+ |
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--發(fā)布查詢root@localhost[(none)]> select count(*) from tempdb.tb1; |
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+----------+| count(*) |+----------+| 1 |+----------+ |
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--查看通用日志文件內(nèi)容root@localhost[(none)]> system more /tmp/suse11b.log |
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mysqld, Version: 5.5.39-log (MySQL Community Server (GPL)). started with:Tcp port: 3306 Unix socket: /var/lib/mysql/mysql.sockTime Id Command Argument141003 16:30:03 1 Query show variables like '%gener%'141003 16:30:09 1 Query select count(*) from tempdb.tb1 |
c、通用查詢?nèi)罩据敵龇绞?/strong>
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--可以輸出為文件，表以及不輸出，即TABLE，F(xiàn)ILE，NONE--系統(tǒng)變量log_outputroot@localhost[(none)]> show variables like 'log_output'; |
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+---------------+-------+| Variable_name | Value |+---------------+-------+| log_output | FILE |+---------------+-------+ |
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--下面修改為輸出為表方式root@localhost[(none)]> set global log_output='TABLE'; |
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Query OK, 0 rows affected (0.00 sec) |
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root@localhost[(none)]> show variables like 'log_output'; |
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+---------------+-------+| Variable_name | Value |+---------------+-------+| log_output | TABLE |+---------------+-------+ |
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--發(fā)布查詢root@localhost[(none)]> select * from tempdb.tb1; |
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+------+------+| id | val |+------+------+| 1 | jack |+------+------+ |
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root@localhost[(none)]> system more /tmp/suse11b.log |
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mysqld, Version: 5.5.39-log (MySQL Community Server (GPL)). started with:Tcp port: 3306 Unix socket: /var/lib/mysql/mysql.sockTime Id Command Argument141003 16:30:03 1 Query show variables like '%gener%'141003 16:30:09 1 Query select count(*) from tempdb.tb1141003 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?nèi)罩据敵龅轿募H僅記錄到全局變量的修改 |
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--mysql.general_log記錄了通用查詢?nèi)罩镜男畔?/code>root@localhost[(none)]> desc mysql.general_log; |
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+--------------+------------------+------+-----+-------------------+-----------------------------+| 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 | |+--------------+------------------+------+-----+-------------------+-----------------------------+ |
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--從通用查詢?nèi)罩颈砝锊榭赐ㄓ貌樵內(nèi)罩镜膬?nèi)容root@localhost[(none)]> select thread_id,command_type,argument from mysql.general_log; |
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+-----------+--------------+---------------------------------------------------------------+| 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 |+-----------+--------------+---------------------------------------------------------------+ |
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root@localhost[(none)]> show variables like 'log_output'; |
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+---------------+-------+| Variable_name | Value |+---------------+-------+| log_output | TABLE |+---------------+-------+ |
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--使用FILE,TABLE 2者混合輸出通用日志root@localhost[(none)]> set global log_output='file,table';<br> |
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Query OK, 0 rows affected (0.00 sec) |
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root@localhost[(none)]> select @@global.log_output; |
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+---------------------+| @@global.log_output |+---------------------+| FILE,TABLE |+---------------------+ |
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root@localhost[(none)]> insert into tempdb.tb1 values(2,'robinson'); |
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Query OK, 1 row affected (0.06 sec) |
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root@localhost[(none)]> commit; |
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Query OK, 0 rows affected (0.01 sec) |
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--驗證結(jié)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 |
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141003 17:41:54 2 Query insert into tempdb.tb1 values(2,'robinson') |
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root@localhost[(none)]> select thread_id,command_type,argument from mysql.general_log -> where argument like '%robinson%'; |
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+-----------+--------------+------------------------------------------------------------------------+| 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'' | +-----------+--------------+------------------------------------------------------------------------+ |
d、關(guān)閉通用查詢?nèi)罩?/strong>
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--可以通過設(shè)置系統(tǒng)變量general_log來關(guān)閉通用查詢?nèi)罩荆藭r日志輸出設(shè)置為FILE,TABLE<br>root@localhost[(none)]> show variables like 'log_output'; |
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+---------------+------------+| Variable_name | Value |+---------------+------------+| log_output | FILE,TABLE |+---------------+------------+ |
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root@localhost[(none)]> set global general_log=off; |
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Query OK, 0 rows affected (0.01 sec) |
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root@localhost[(none)]> show variables like '%gener%'; |
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+------------------+------------------+| Variable_name | Value |+------------------+------------------+| general_log | OFF || general_log_file | /tmp/suse11b.log |+------------------+------------------+ |
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root@localhost[(none)]> delete from tempdb.tb1 where id=2; |
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Query OK, 1 row affected (0.12 sec) |
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root@localhost[(none)]> commit; |
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Query OK, 0 rows affected (0.00 sec) |
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root@localhost[(none)]> system tail -n 1 /tmp/suse11b.log |
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141003 17:45:13 2 Query set global general_log=off |
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root@localhost[(none)]> select thread_id,command_type,argument from mysql.general_log -> where argument like '%delete%'; |
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Empty set (0.00 sec)<p>--從上面的演示可知，盡管我們設(shè)置了log_output為FILE,TABLE，但general_log為OFF，通用日志無任何記錄產(chǎn)生</p> |
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root@localhost[(none)]> set global log_output=none; |
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Query OK, 0 rows affected (0.00 sec) |
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root@localhost[(none)]> set global general_log=1; |
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Query OK, 0 rows affected (0.00 sec) |
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root@localhost[(none)]> truncate table tempdb.tb1; |
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Query OK, 0 rows affected (0.01 sec) |
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root@localhost[(none)]> system tail -n 1 /tmp/suse11b.log |
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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。 |
