Hive Interview Questions and Answers

1. Does Hive support record level Insert, delete or Update?

Hive does not support recode level insert, delete or update. It doesn’t provide transactions also. If the user can go with CASE statements and built-in functions of Hive to satisfy the insert, update and delete.

2. What kind of data warehouse applications is suitable for Hive?

Basically, Hive is not a full database it is a data summarization tool in Hadoop eco-system. Hive can do below applications:

I)Fast response times are not required
II)When the data is not changing rapidly
III)Relatively static data is analyzed

3. How can the columns of a table in Hive be written to a File?

In Hive using the awk command in Hive shell, the output from HiveQL can be written to a file

Example : hive -S -e  "describe table_name" | awk -F " '{print 1}' > ~/output

4.Difference between order by and sort by in Hive?

In Hive SORT BY will sort the data within each reducer. It can use any number of reducers for SORT BY operations.
Coming to ORDER BY will sort all of the data together, which has to pass through one reducer. Thus, ORDER BY in Hive uses single reducers and guarantees total order in the output while SORT BY only guarantees ordering of the rows within a reducer




5. Wherever Different directory I run Hive query, it creates new metastore_db, please explain the reason for it?

Whenever you run the Hive in embedded mode, it means that it creates the local metastore. And before creating the metastore it looks whether metastore already exists or not. This property is defined in the configuration file in hive_site.xml properties.

"javax.jdo.option.ConnectionURL" with default value

"jdbc:derby::databaseName=metastore_db";create=true

6. Is it possible to use the same metastore by multiple users, in case of embedded Hive?

No, it is impossible to use metastore for multiple users, it is only for a single user in a single mode database like PostgreSQL, MySQL, etc.