如何在不重新启动 MySQL 的情况下启用 MySQL 的慢查询日志?

我按照这里的说明操作:http://crazytoon.com/2007/07/23/mysql-changed-runtime-variables-with-out-restarting-mysql-server/ 但这似乎只是设置了阈值.>

我还需要做其他事情吗，比如设置文件路径?

根据 MySQL 的文档

<前>如果没有为 --log-slow-queries 提供 file_name 值，则默认名称为主机名-slow.log.服务器在数据目录中创建文件，除非给出绝对路径名以指定不同的目录.

运行

显示变量

不指示任何日志文件路径，并且我在我的服务器上没有看到任何慢查询日志文件...

编辑

看起来我使用的是服务器版本 5.0.77，所以我需要做:

SET GLOBAL log_slow_queries = 1;

但我得到:错误 1238 (HY000):变量log_slow_queries"是只读变量

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

解决方案

尝试 SET GLOBAL slow_query_log = 'ON'; 或者 FLUSH LOGS;

这假设您使用的是 MySQL 5.1 或更高版本.如果您使用的是早期版本，则需要重新启动服务器.这在 MySQL 手册中有记录.您可以在配置文件或命令行中配置日志.

I followed the instructions here: http://crazytoon.com/2007/07/23/mysql-changing-runtime-variables-with-out-restarting-mysql-server/ but that seems to only set the threshold.

Do I need to do anything else like set the filepath?

According to MySQL's docs

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. 

Running

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;

but I get: ERROR 1238 (HY000): Variable 'log_slow_queries' is a read only variable

I assume I'm going to need to restart the server and have log_slow_queries set in my config?

解决方案

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.