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I am using mariadb and I to investigate some issue I wanted to check the logs. To my surprise, log file is not generated for mariadb.

I suspect this cannot be the case so I am doubting my search skills. 

MariaDB [(none)]> show variables like 'log_error'
    -> ;
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| log_error     |       |
+---------------+-------+
1 row in set (0.00 sec)

I have added the entry in my.cnf still above field is coming to be empty.

[root@cslcodev11-oem ~]# cat /etc/my.cnf
[mysqld]
!includedir /etc/mysqld/conf.d
datadir=/mnt/mgmt/var/lib/mysql
socket=/var/lib/mysql/mysql.sock
tmpdir=/mnt/mgmt/var/lib/mysql_tmp
user=mysql
# Disabling symbolic-links is recommended to prevent assorted security risks
symbolic-links=0
### TRT-3229 #####
sync_binlog=1
innodb_flush_method=O_DIRECT
innodb_support_xa = 1
myisam_repair_threads = 2
myisam_recover_options = FORCE
###################
innodb_file_per_table=1
innodb_log_buffer_size = 8M
table_open_cache=256
max_heap_table_size=256M
### TRT-4685 ###
max_connections=500
################
innodb_log_file_size = 512M

[mysqld_safe]
log-error=/var/log/mariadb/mysqld.log
pid-file=/var/run/mysqld/mysqld.pid
[root@cslcodev11-oem ~]#

So, I want to know do we have any default location where these logs are getting generated, if the path cannot be read from config files.

Update:

After some investigation, I found this information,

Reference: https://mariadb.com/kb/en/mariadb/error-log/

Activating the Error Log

The error log is active by default. The log-error=filename option determines where the output will be written. If no file name is specified, the log will be written to host-name.err. If no absolute path is specified, the file will be written to the data directory (determined by the value of the datadir system variable).

On Unix systems, if the --log-error option is not used, the errors are written to stderr (usually, the command line).

On Windows, if the --console option is specified, and --log-error is not used, the errors are written to the console. If --log-error is present, --console is ignored.

So now I understand that due to some reason the configuration log_error in my.cnf is not considered. So as per the suggestion, on Unix system, if --log-error is not used, logs are redirected to stdout.

BUT, I am starting the service using service mysqld start command so I want to know what all options are used by default when we start the service using service mysql start? ESP, is --log-error used?

Bhupesh Pant
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1 Answers1

0

If you're presently using a 2023 version of MariaDB, and if you already activated the MariaDB logs, one of those commands below might show the log location. Which command works depends on your operating system:

mariadbd --print-defaults

or

mariadb --print-defaults

or

my_print_defaults --mysqld | grep log-error

"If the above don't help, check also if your system is set to write to syslog, in which case you need to use journalctl to access it."

Source at https://mariadb.com/kb/en/error-log/

Francewhoa
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