[HIVE-1011] GenericUDTFExplode() throws NPE when given nulls

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 0.6.0
• Component/s: Query Processor
• Hadoop Flags: Reviewed
• Assignee: Paul Yang
• Reporter: Paul Yang
• Created: 23/Dec/09 23:37
• Updated: 17/Dec/11 00:03
• Resolved: 12/Apr/10 19:45

Description

When explode() is called on rows where the array column is null, a null pointer exception is thrown.

For example consider having a table named test with the following rows

key     value
1       [1,2,3]
2       null 

Then running the query

SELECT explode(value) AS myCol FROM test;

or

SELECT * FROM test LATERAL VIEW explode(value) myTab AS myCol;

will throw a null pointer exception when explode() gets the null value from the 2nd row.

Possible options are:

1. Treat null values as an error and make the user fix null values in data
2. explode(null) generates a null output value.
3. explode(null) generates no output values

#2 means that explode(null) and explode(array(null)) will behave identically. Because of that, I think #3 makes the most sense.