Manual:$wgTmpDirectory/de-formal

Details
The local filesystem path to a temporary directory. This is required to be writable. It shouldn't be accessible from the web, so try to place it outside of the document root (recommended) or at least deny any access from the web via .htaccess or webserver configuration. Having files from this folder accessible from the web can be a security risk.

$wgTmpDirectory is used by  to control where MediaWiki writes temporary files to, including:

Can be overridden using.
 * Old and new tempfiles for external executable based external diff engines configured by
 * - used for chunked uploading, some transformations, and various parts of the file backend code
 * UID Generator node and lock files.
 * Upload from URL
 * The directory in which a CACHE_DBA cache places its DBA database file.
 * Importing uploads from XML dumps
 * - used for SVG transformation

Common pitfalls
If you are getting this error, an incorrect setting for $wgTmpDirectory often is the cause:

Warning: rename(/tmp/l10n_cache-en.cdb.tmp.335721450,/tmp/l10n_cache-en.cdb): Operation not permitted in /.../vendor/wikimedia/cdb/src/Writer/DBA.php on line 59

Fatal exception of type MWException: Warning: dba_close: supplied resource is not a valid DBA identifier resource in /.../vendor/wikimedia/cdb/src/Writer/DBA.php on line 54

Fatal error: Uncaught Cdb\Exception: Unable to move the new CDB file into place. in /.../vendor/wikimedia/cdb/src/Writer/DBA.php:60

The solution is to set $wgTmpDirectory to a folder, which actually is writable by the webserver user.

Sometimes it is useful to have separate directories for the web server and CLI user, if they require different permissions. For example:

See for more information!

Usage in unsupported MediaWiki versions
The path to the temporary directory. When using CACHE_DBA as your, this allows you to select which directory is used.