[SPARK-27841] Improve UTF8String fromString()/toString()/numChars() performance when strings are ASCII

• Type: Improvement
• Status: In Progress
• Priority: Major
• Resolution: Unresolved
• Affects Version/s: 3.1.0
• Component/s: SQL
• Assignee: Josh Rosen
• Reporter: Josh Rosen
• Created: 25/May/19 23:29
• Updated: 16/Mar/20 22:52

Description

UTF8String's fromString(), toString(), and numChars() methods are performance hotspots. For strings which consist entirely of ASCII characters we can make performance optimizations which significantly reduce memory allocation and copying, greatly improving performance for many common workloads.

Issue Links

• links to: GitHub Pull Request #24709