ejabberd add_rosteritem process_rosteritems

Hello, I am fairly new to ejabberd and I am trying to use it with an external DB, Azure SQL server.

Almost everything works fine (except for a connection problem I talk about in another post).

What I am trying to understand better now, are the add_rosteritem and process_rosteritems commands.
I use add_rosteritem to add users to each others rosters, like so:

ejabberdctl add_rosteritem localuser localserver user server nick group subs

where subs is always "both". This command also create a record in the rostergroups table, as it seems I have to specify a group even tough I dont want to (I use a group called "all" for convenience) or the command does not work.

Point is, if I run "process_rosteritems list any any any any" all I get is "There are 0 roster items in total."

Any suggestion? thanks!