[HIVE-253] rand() gets precomputated in compilation phase

• Type: Bug
• Status: Closed
• Priority: Blocker
• Resolution: Fixed
• Affects Version/s: 0.6.0
• Fix Version/s: 0.3.0
• Component/s: Query Processor
• Hadoop Flags: Reviewed
• Assignee: Raghotham Murthy
• Reporter: Zheng Shao
• Created: 28/Jan/09 00:52
• Updated: 17/Dec/11 00:09
• Resolved: 18/Mar/09 22:02

Description

SELECT * FROM t WHERE rand() < 0.01;

Hive will say: "No need to submit job", because the condition evaluates to false.

The rand() function is special in the sense that every time it evaluates to a different value. We should disallow computing the value in the compiling phase.

One way to do that is to add an annotation in the UDFRand and check that in the compiling phase.

Issue Links

• duplicates: HIVE-325 [Hive] rand() should be ignored by input pruning