Details
Major Description
For `desc table ` queries, DescTableOperation always creates a Deserializer object, even though it's not often needed.
What is worse is that if a table is backed on some particular SerDe class, uses have no chance to desc table without adding appropriate jar files. With this patch, users at least are able to desc tables when they only need metadata of the table, especially in a shared Hive environment.
For above two reasons, it's better to create Deserializer object only when it's needed.