http://dev.mysql.com/doc/refman/5.5/en/handler.html
Seems to be very useful for PK lookups, but I haven't seen much information regarding this. What's the pros and cons of the handler syntax vs. ordinary SQL select for simple key-value queries? How does it compare (performance- and consistence-wise) to HandlerSocket?

HANDLERwith the DBA.SE before asking the question. I'll give you a +1 anyway because it is a legitimate subject in the MySQL realm. – RolandoMySQLDBA Nov 22 '12 at 22:33