MySQL 8 Administrator???s Guide

MySQL temporary files storage

The value of the TMPDIR environment variable is used by MySQL on the Unix as the path name of the directory to store temporary files. MySQL uses a system default, such as/tmp, /var/tmp, or /usr/tmp if the TMPDIR is not set.

The values of the TMPDIR, TEMP, and TMP environment variables are checked by MySQL on Windows. If MySQL finds one set, it uses that value and does not check for remaining values. If none of these three variables are set, MySQL uses the system default, which is C:\windows\temp\.

If the temporary file directory in the filesystem is too small, we can use the mysqld --tmpdir option to specify a directory on the filesystem with enough space. For the replication, on slave machines, we can use