Tukukkk

I have a scenario where I have two Hive tables, and the second one is essentially an evolved schema of the first (it has 1 more column in this example).

Table_A

{

business_date String

Name String

Age Number

} partitioned by business_date



Table_B {

business_date String

Name String

Age Number

Address String

} partitioned by business_date

In order to obfuscate downstream users from schema changes, I am creating a Hive view with the following syntax:

Create VIEW customer_info AS 

select * from Table_B 

UNION 

select business_date, name, age, null as address from Table_A

I know the above returns all the data, but from a performance standpoint, if a query run against the view with a valid business_date value, does it take the partition key into account? Or do I lose this benefit when working with views?

Edit: I should mention that business_date is actually a unique value across all partitions. This means, that data provided in Table_A, should not be provided in Table_B. Think of Table_A as being an "older version" of data. Given this, is this the best approach of serving the data if the goal is to abstract schema changes away from the end consumers?

Edit#2: Storing this data in one table is not possible due to tons of other problems.

You are not using any partition predicates in your query, that is why it will be no partition pruning. Use explain command to check this, it will show partition predicates applied. Partition pruning should work fine with a view.

If business_date is unique value across all partitions then using UNION makes no sense here because all rows are unique. UNION is the same as UNION ALL+DISTINCT.
Use UNION ALL instead, it will perform much better.