ApsaraDB for Memcache uses Tair internally and provides services using Memcached interfaces. The semantics of each command and the returned error values are consistent, which allows almost seamless switchover between ApsaraDB for Memcache and Memcached. The two differences are as follows:
The operands of Increment and Decrement are 64-bit unsigned integers in Memcached and 32-bit unsigned integers in ApsaraDB for Memcache. In addition, the operation results on the string data is different.
The CAS value is a 32-bit unsigned integer in Memcached and a 16-bit unsigned integer in ApsaraDB for Memcache. It does not have any impact on the developers.