debusine-server-delete-expired keeps failing

The last message before failing is

Deleting NN expired workspaces

The number NN grows monotonically from one run to the next. Very likely expiration for workspaces fails somehow.

Possibly related:

Lock timed out (5 seconds). Try again.

and:

CommandError: Database error: ("Cannot delete some instances of model 'FileInArtifact' because they are referenced through protected foreign keys: 'FileUpload.file_in_artifact'.", {...})