1.Difference between manage table and external table? 2.which table is used in production and why? 3.What are the challenges we are facing while using that table in real time and how can we overcome that?
1a)Managed table and External table in Hive There are two types of tables in Hive ,one is Managed table and second is external table. the difference is , when you drop a table, if it is managed table hive deletes both data and meta data,if it is external table Hive only deletes metadata.
2a)Managed tables are created when you have to make particular optimizations like add or remove columns. External tables only mirror the raw data that is brought into the system. Sometimes some jobs require or work better when the table is restructured. So this is done with managed tables. In terms of data loss, data and system losses are treated as facts of life in a Hadoop environment and must be designed for.