"IMPORT INTO" uses only the "RocksDB"-engine, not the "Titan"-engine?

[heyciao]

File: /release-8.5/sql-statements/sql-statement-import-into.md
I have started a few weeks ago to try to use TiDB and so far it was a nice experience, as well because of the very nice documentation - thank you 😄

In the config of my test installation I have the parameter "titan.enabled: true" and when I insert large records into my tables I see that files in "../tikv-20160/db/titandb/" are written.

A few days ago I used the "import into"-functionality and once the job had finished executing (successfully) I noticed that nothing got written into the directory "../tikv-20160/db/titandb/" where the titan files reside - only its parent directory had new sst-files (and I assume that all what's in that parent directory are files related to RocksDB).

If I did not make a mistake or overlooked some parameter, then I assume that the "import into"-functionality cannot currently use the "titan"-engine, respectively, that it will always write all data into TiDB's RocksDB engine?
If this is correct then it would be nice to mention this in the documentation.

Cheers
Stefano