Manual:$wgTmpDirectory

Details
The local filesystem path to a temporary directory. This is required to be writable. It is not required to be accessible from the web.

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

used for chunked uploading, some transformations, and various parts of the file backend code
 * Old and new tempfiles for external executable based external diff engines configured by 


 * UID Generator node and lock files.


 * Upload from URL

Can be overridden using  .
 * The directory which a man>Special:MyLanguage/Manual:$wgMainCacheType|CACHE_DBA cache places it's 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.

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.