User creating group and inviting a seemingly random large amount of members

The user with ID 963770 at 2017-01-24 02:44:11.428056+00, then created the group www185096com009 and proceeded to invite 1981 other users to this group. I could not find any pattern in the Email addresses, which suggests the users are invited randomly (instead of e.g. being colleagues). This process in turn seems to produce a large increase in SQL queries:

This also seems to have lead to users complaining on Twitter about getting spammed: https://twitter.com/tosbourn/status/823819491553509376

The query counts seem to be the result of the problem described in https://gitlab.com/gitlab-org/gitlab-ce/issues/27148, which is most likely an N+1 query problem.

The user in question has been disabled using the following SQL query:

update users set state = 'blocked', locked_at = now(), can_create_group = false where id = 963770;