Facebook wanted to analyze their petabytes of data but didn't have time to train data analysts to write Java MapReduce programs. Moreover, as the analysts were aware of SQL, they invented this tool "HIVE".
Instead of writing multiple lines of MapReduce, you can write a query and get your desired results.
In a Facebook page, data or news feed keeps changing frequently. NoSQL database, which is technically faster than RDBMS is leveraged here.
The analytics can be accomplished using Hive, and for random access to this analytics, HBase is leveraged.
