如何在不重新启动 MySQL 的情况下启用 MySQL 的慢速查询日志？

我按照这里的说明: http://crazytoon.com/2007/07/23/mysql-changing-runtime-variables-with-out-restarting-mysql-server/，但这似乎只设置了阈值。

我是否需要执行其他操作，比如设置文件路径？

根据 MySQL 的文档

If no file_name value is given for --log-slow-queries, the default name is
host_name-slow.log. The server creates the file in the data directory unless
an absolute path name is given to specify a different directory.

跑步

SHOW VARIABLES

doesn't indicate any log file path and I don't see any slow query log file on my server...

EDIT

Looks like I'm using server version 5.0.77, so I needed to do:

SET GLOBAL log_slow_queries = 1;

但是我得到: ERROR 1238(HY000) : 变量‘ log _ slow _ query’是一个只读变量

我假设我需要重新启动服务器并在我的配置中设置 log _ slow _ query？

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小开

I think the problem is making sure that MySQL server has the rights to the file and can edit it.

If you can get it to have access to the file, then you can try setting:
SET GLOBAL slow_query_log = 1;

If not, you can always 'reload' the server after changing the configuration file. On linux its usually /etc/init.d/mysql reload

小开

Try SET GLOBAL slow_query_log = 'ON'; and perhaps FLUSH LOGS;

This assumes you are using MySQL 5.1 or later. If you are using an earlier version, you'll need to restart the server. This is documented in the MySQL Manual. You can configure the log either in the config file or on the command line.

小开

MySQL Manual - slow-query-log-file

This claims that you can run the following to set the slow-log file (5.1.6 onwards):

set global slow_query_log_file = 'path';

The variable slow_query_log just controls whether it is enabled or not.

小开

These work

SET GLOBAL LOG_SLOW_TIME = 1;
SET GLOBAL LOG_QUERIES_NOT_USING_INDEXES = ON;

Broken on my setup 5.1.42

SET GLOBAL LOG_SLOW_QUERIES = ON;
SET GLOBAL SLOW_QUERY_LOG = ON;
set @@global.log_slow_queries=1;

http://bugs.mysql.com/bug.php?id=32565

Looks like the best way to do this is set log_slow_time very high thus "turning off" the slow query log. Lower log_slow_time to enable it. Use the same trick (set to OFF) for log_queries_not_using_indexes.

小开

For slow queries on version < 5.1, the following configuration worked for me:

log_slow_queries=/var/log/mysql/slow-query.log
long_query_time=20
log_queries_not_using_indexes=YES

Also note to place it under [mysqld] part of the config file and restart mysqld.

小开

Find log enabled or not?

SHOW VARIABLES LIKE '%log%';

Set the logs:-

SET GLOBAL general_log = 'ON';


SET GLOBAL slow_query_log = 'ON';
小开

This should work on mysql > 5.5

SHOW VARIABLES LIKE '%long%';

SET GLOBAL long_query_time = 1;

小开

If you want to enable general error logs and slow query error log in the table instead of file

To start logging in table instead of file:

set global log_output = “TABLE”;

To enable general and slow query log:

set global general_log = 1;
set global slow_query_log = 1;

To view the logs:

select * from mysql.slow_log;
select * from mysql.general_log;

For more details visit this link

http://easysolutionweb.com/technology/mysql-server-logs/


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