Hi Iwona -
This information is captured in the PostgreSQL DB. Take a look at the Workgroup data dictionary (link below). This will provide a list of tables available for query.
I have looked there, but haven't found table capturing this specific information, maybe you can give me a table name where this is captured?
See if this will help get you started ... the http_request_uri only filters out where they download it to a csv file.
r.user_id as "User ID - Site",
u.system_user_id as "User ID - System",
su.name as "User Name",
su.friendly_name as "Friendly Name",
INNER JOIN http_requests r ON vd.vizql_session = r.vizql_session
INNER JOIN users u ON r.site_id = u.site_id AND r.user_id = u.id
INNER JOIN system_users su ON u.system_user_id = su.id
r.action = 'show' AND
vd.action = 'vud' AND
vd.http_request_uri like '%csv=true%'
Thank you, this is very helpful.