The difference between vernacular Redis and memcached

If you simply compare the difference between Redis and memcached, the external difference is:

1 Redis not only supports simple k/v-type data, but also provides storage of data structures such as List,set,zset,hash.

2 Redis supports backup of data, that is, Master-slave mode of data backup.

3 Redis supports data persistence, which keeps the in-memory data on disk and can be loaded again when it is restarted.

Comparison of key technologies for memcached and Redis

Memcached's idea is to pre-apply many different sizes of memory into a number of groups, storage objects come, by size in the smallest can accommodate this object in the space, the advantage is that the object does not need to temporarily apply for memory, the disadvantage is that there will be wasted memory space.

The idea of Redis is that when an object comes in, it applies memory to the size of the object that has already been calculated, and then puts it in the head position of the memory, and then does not have to calculate the size again in the future operation. Equivalent to the need for time to calculate the results of preservation, and later use will not be calculated, using space for time to optimize the original memory management mode.

Comparison of cluster implementation mechanism between REDIS and memcached

Memcached calculates the distribution position on the client side in a consistent Hashi manner.

Redis is used in the server implementation of the cluster, the implementation of cluster concept, the client arbitrary access to nodes, the nodes will communicate with each other, complete data access. And because the nodes can communicate with each other, there is a master-slave mechanism, the data on one node is synchronized to other nodes, and the data will not be lost after the sudden outage.

The difference between vernacular Redis and memcached