function Operator:allocateStorage(size)
     local db = self:acquireDatabase()
     while db:getAvailableSpace() < size do
         local dated_item = db:query{
             number = 1,
             tag = "emotion",
             sort = "timestamp",
         }
         db:remove(dated_item)
     end
     local chunk = db:reserveSpace(size)
     zeroMemory(chunk)

return chunk end