[SPARK-33092] Support subexpression elimination in ProjectExec

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 3.1.0
• Fix Version/s: 3.1.0
• Component/s: SQL
• Assignee: L. C. Hsieh
• Reporter: L. C. Hsieh
• Created: 08/Oct/20 05:45
• Updated: 12/Oct/20 07:55
• Resolved: 12/Oct/20 07:55

Description

Users frequently write repeatedly expression in projection. Currently in ProjectExec, we don't support subexpression elimination in Whole-stage codegen. We can support it to reduce redundant evaluation.

Issue Links

• relates to: SPARK-32989 Performance regression when selecting from str_to_map
• links to: [Github] Pull Request #29975 (viirya)