MariaDB /tmp file filling with MAD file

15 January,2020 by Rambler

Question: I've received an alert from a RHEL server with MariaDB installed. The alert refers to a MAD file filling the /tmp drive . What is going on? and how can I fix the mysql MAD file filling the /tmp drive?

Answer: This is a common problem when under certain circumstances - CREATE & ALTER statements executed on InnoDB tables create a temporary table in mysql's tmpdir.   

To find out the current value check my.cnf  or use SHOW VARIABLES LIKE "TMPDIR

During the data load phase MariaDB creates a temporary table in /tmp - which consequently fills the /tmp

The quick fix is to alter the tmpdir value in my.cnf and restart mysql  .   Find the directory which has enough disk space to support the load requirement.

Before you load the data you can check the tmpdir variable. 



| Variable_name | Value |
| tmpdir | /tmp |
1 row in set (0.01 sec)


Go to the my.cnf   file and add\modify the tmdir variable. Ensure the  entry is placed in the [mysqld] section.

Restart the mysql service :  service mysql restart       and check  SHOW VARIABLES LIKE "TMPDIR";





Author: Rambler (


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