The MySQL server now includes the widely used memcached in-memory caching system, and a plugin that allows fast NoSQL-style access to InnoDB tables through the memcached protocol. This access method avoids the overhead of SQL parsing and constructing a query optimization plan. You can store the underlying data in a single InnoDB table, or spread it across multiple tables. You can read and write data through both memcached and SQL. For example, you can do fast single-key lookups through memcached get calls, and do statistical reports across all the data through SQL.
Advanced users can enable the traditional memcached in-memory caching and control whether operations look up and store data in memory, in InnoDB tables, or both.
One of the versions[1] of the 5.6 documentation[2] has a comment regarding that.
> This configuration differs from another popular MySQL NoSQL solution, HandlerSocket, by skipping even the Handler API layer and directly accessing the InnoDB storage engine through low-level APIs, making the code path even shorter and more efficient.
The MySQL server now includes the widely used memcached in-memory caching system, and a plugin that allows fast NoSQL-style access to InnoDB tables through the memcached protocol. This access method avoids the overhead of SQL parsing and constructing a query optimization plan. You can store the underlying data in a single InnoDB table, or spread it across multiple tables. You can read and write data through both memcached and SQL. For example, you can do fast single-key lookups through memcached get calls, and do statistical reports across all the data through SQL.