MySQL Tutorial

MySQL Installation and Configuration

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MySQL set log output mode

MySQL allows you to determine where the server sends output for the General Query Log and the Slow Query Log by setting the log_output system variable. This setting can take one or multiple of the following values:

FILE: Writes log output to files.
TABLE: Writes log output to tables in the mysql database (general_log and slow_log).
NONE: Disables logging, which can be used to temporarily disable the logs without changing the other log_output settings.

The default value for log_output is FILE.

Setting the log output mode

You can set the log_output mode in your MySQL configuration file (my.cnf or my.ini). Here's an example that sets log_output to TABLE:

[mysqld]
log_output=TABLE

In this example, MySQL will write general and slow query logs to the general_log and slow_log tables in the mysql database.

You can also set the log_output mode to both FILE and TABLE:

[mysqld]
log_output=TABLE,FILE

In this example, MySQL will write general and slow query logs to both files and tables. The log file names are determined by the general_log_file and slow_query_log_file system variables.

You can also change the log_output value dynamically while the server is running using the SET command. For example:

SET GLOBAL log_output = 'TABLE';

This command will set the global log_output value to TABLE. Note that this change is not persistent and will be reset when the server restarts.

Note: Modifying the MySQL configuration file and changing system variables typically require administrative privileges. Always be careful when modifying configuration files and ensure to back up any files before you modify them.

MySQL set log output mode:
- Description: Set the log output mode to control where MySQL writes log information.
- Example (Write logs to a file):
```
[mysqld]
log_output = FILE
```
Change log format in MySQL:
- Description: Change the log format to customize the information included in the logs.
- Example (Set log format to JSON):
```
[mysqld]
log_output = FILE
log_json = ON
```
Configuring log output mode in MySQL:
- Description: Configure the log output mode to determine where log information is written.
- Example (Write logs to the console):
```
[mysqld]
log_output = CONSOLE
```
Switching log output modes in MySQL:
- Description: Switch between different log output modes to change where log information is stored.
- Example (Switch to writing logs to a table):
```
[mysqld]
log_output = TABLE
```
Customize log output in MySQL:
- Description: Customize log output by adjusting configuration options based on your requirements.
- Example (Customize general query log output):
```
[mysqld]
general_log = 1
general_log_file = /path/to/general-query.log
```
Log verbosity levels in MySQL:
- Description: Adjust the verbosity level to control the amount of detail included in the logs.
- Options include ERROR, WARN, INFO, DEBUG, and TRACE.
- Example (Set log verbosity to INFO):
```
[mysqld]
log_error_verbosity = 2
```
Setting log levels in MySQL:
- Description: Set specific log levels to filter the type of information included in the logs.
- Example (Set error log level to warnings only):
```
[mysqld]
log_error_verbosity = 1
```
Adjusting logging options in MySQL:
- Description: Adjust various logging options to fine-tune the behavior of MySQL logs.
- Example (Adjust the number of log files to keep):
```
[mysqld]
log-bin = /path/to/mysql-bin
expire_logs_days = 7
```