[IMPALA-1861] Conditional functions with constant arguments should be simplified during analysis

• Type: Improvement
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: Impala 2.2
• Fix Version/s: Impala 2.9.0
• Component/s: Frontend
• Labels: impala performance
• Target Version: Product Backlog
• Assignee: Thomas Tauber-Marshall
• Reporter: Dimitris Tsirogiannis
• Created: 09/Mar/15 20:40
• Updated: 23/Aug/17 17:45
• Resolved: 17/Apr/17 15:30

Description

The frontend should be able to detect conditional functions with constant predicates (e.g. IF(true, expr1, expr2)) and automatically replace them with the correct result during the analysis.

Issue Links

• breaks: IMPALA-5125 Check failed: tuple_desc_map_.back() != __null
• breaks: IMPALA-5725 coalesce() not being fully applied with outer joins on kudu tables
• is duplicated by: IMPALA-4491 Avoid reading columns that are only part of constant expressions in select
• is related to: IMPALA-1788 Consider replacing constant exprs with literal equivalents