purge_history api does not delete media

[SPiRiT369]

I want to delete old room messages. (unencrypted room)

I use purge_history call (/_synapse/admin/v1/purge_history/<room_id>) and it does the work. However, if the deleted events contain uploaded media - they are removed from the room but not from the disk.

Please fix it so purge_history will also delete files from disk.

A workaround for this issue could be to use the delete media api, but it works on all rooms, and I want to clean history on specific rooms only.

[dklimpel]

IMO this is not possible. Purge history deletes also encrypted events. And the server does not know the content / media files of this event.
Also you can use a media in multiple events.

[SPiRiT369]

If the room is unencrypted then it's possible to delete those files I think. Because it's possible to list room media via api.

[dklimpel]

Related #10176

[SPiRiT369]

It is not related. It's for empty rooms. I am speaking about active rooms that I want to clean old messages in them.

[richvdh]

The difficulty here is that media is not particularly linked to a specific event (or even room): there is nothing to say a single media url has not been used in multiple places.

This is covered by a range of existing issues, such as #1263, #6832, https://github.com/matrix-org/matrix-doc/issues/701, matrix-org/matrix-spec-proposals#2278

[SPiRiT369]

Oh @richvdh thank you for this info. I didn't know that it's a duplicate. Sorry for creating another one.
At least it's a known issue. I hope it will be solved somewhere soon. Synapse leaves too much storage junk 😕
Thanks again.