redis 内存计算公式 k:74+x+y=17+key+ 24+16+ 17+valueH:57+x+N(74+y+Z)=17+key 24 +16 +n(74+field+value)Set:57+x+N(57+y)=17+key+ 24 +16 + N(57+value)L:57+X + N(41+value)