Tableau Server "dataengineextract" Folder Consumes Disk Space

Issue

When backgrounder process exits unexpectedly during an extract refresh, the temporary extract file and old (and orphaned) extracts files are not reaped from the extract folder.
Temporary extract file has been left under working directory that is named with _TDFSTRNSFR.
The files are stored on the server location like below:
C:\ProgramData\Tableau\Tableau Server\data\tabsvc\dataengine\extract\05\e1\{66C5A7DE-E58C-4D44-B706-3D4D33D109BF}_TDFSTRNSFR\TestDS.hyper

Environment

Tableau Server 2018.1, 2018.2 and 2018.3

Resolution

Option 1
Manually delete dataengine\extract\##\{FOLDERID}_TDFSTRNSFR\*.hyper file that are more than 24 hours old since last update date. Tableau Server can be running while deleting these files.

Option 2
Upgrade Tableau Server to versions 2018.1.10 / 2018.2.7 / 2018.3.4 and later. Then orphaned .hyper files under *_TDFSTRNSFR temporary folder will be deleted when Tableau Server is restarted.

Cause

There was a known issue since Tableau Server 2018.1. Temporary ongoing hyper file for refresh extract are created under dataengine\extract\##\{FOLDERID}_TDFSTRNSFR directory.
When the backgrounder process fails during extract refresh, the hyper file under {FOLDERID}_TDFSTRNSFR is left orphaned without any references and causing disk space shortage.