Get memory consumption for redis hset data type with uuid is key. Change KEY_SIZE to experiment with different values.

test_redis_memory.rb

require 'securerandom'

KEY_SIZE = 5
MILLIONS = 10

def key_name(uu_id)
  "sk_#{uu_id[0..(KEY_SIZE-1)]}"
end

def field_name(uu_id)
  uu_id[KEY_SIZE..-1]
end

# https://redis.io/topics/mass-insert
def gen_redis_proto(*cmd)
  proto = ""
  proto << "*"+cmd.length.to_s+"\r\n"
  cmd.each{|arg|
    proto << "$"+arg.to_s.bytesize.to_s+"\r\n"
    proto << arg.to_s+"\r\n"
  }
  proto
end

# import 1 million records into redis
def import()
  m = []
  (1..1000000).each do |i|
     m << [SecureRandom.uuid, rand(10)].freeze
  end

  file_path = '/tmp/redis_loads.txt'
  f = open(file_path, 'w')
  m.each do |v|
    f.puts(
       gen_redis_proto(
         "HSET",
         key_name(v[0]),
         field_name(v[0]),
         v[1]
      )
    )
  end
  f.close

  system("cat #{file_path} | redis-cli --pipe; rm #{file_path};")
end

# delete all redis data
system("redis-cli flushall;")
# import random records to redis
MILLIONS.times{ import() }
# get used memory (used_memory_peak_human requires restarting redis)
system("redis-cli info | grep used_memory_human;")