tables = Restaurant.find_by_sql("
SELECT nspname || '.' || relname AS relation,
    pg_size_pretty(pg_relation_size(C.oid)) AS size
  FROM pg_class C
  LEFT JOIN pg_namespace N ON (N.oid = C.relnamespace)
  WHERE nspname NOT IN ('pg_catalog', 'information_schema')
  And relname like 'bill_calculations_%'
  ORDER BY pg_relation_size(C.oid) DESC")

ids = []
tables.each do |t|
  id = t.relation.split('public.bill_calculations_')[1].gsub('_', '-')
  ids << id if id.to_s != 'copy-pkey'
end
ids.each_with_index do |id, i|
  r = Restaurant.find_by_id(id)
  if r
    r.shard = "staging_shard#{i%4}"
    r.save
  end
end