-- argv: ns
local ns = KEYS[1]
local groupsKey = ns .. ":groups"
local groupIds = redis.call("SMEMBERS", groupsKey)
local groups = {}
for _, groupId in ipairs(groupIds) do
  local gZ = ns .. ":g:" .. groupId
  local jobCount = redis.call("ZCARD", gZ)
  if jobCount > 0 then
    table.insert(groups, groupId)
  end
end
return groups