Redis interview questions

Redis Interview questions

1.redis What is it? ？

redis It's a key-value Non relational database , Read data fast , It can be used as a cache to reduce the load pressure of the database .

2.redis What data types are supported ？

redis There are five types , Namely String,list,hash,set,zset

（1）String type ： Can store any type of data , Like strings , Integers and floating point numbers

（2）list type ： Its structure is data duplication , Orderly

（3）hash type ： Its structure is value It's divided inside key-value, Suitable for storing object data

（4）set type ： Its structure is that the data cannot be repeated , disorder

（5）zset type ： Its structure is that the data cannot be repeated , Orderly

2. Suitable for the scene

1） Cache data

2） Distributed lock

3.Redis key How to set the expiration time and permanent validity of ?

EXPIRE and PERSIST command

4.redis How to implement distributed locks ？

5.redis The persistence of

redis Persistence has RDB Strategy ,AOF Strategy ,redis Persistence of means redis Will write the data in the memory to the hard disk , stay redis Load this data on reboot , So as to minimize the impact of cache loss .

RDB Strategy ： The frequency of persistence is not high , Data loss is serious , Data security is low , but redis It provides users with higher performance of operating data

AOF Strategy ： Second persistence , With higher data security , If the server crashes , Only lose 1 Seconds of data