[HIVE-22191] Simplify SemanticAnalyzer by removing unused code

• Type: Task
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 4.0.0-alpha-1
• Component/s: CBO, Hive
• Assignee: Akos Dombi
• Reporter: Akos Dombi
• Created: 11/Sep/19 08:03
• Updated: 17/Nov/22 08:50
• Resolved: 30/Sep/19 11:23

Description

Simplify SemanticAnalyzer by:

• Remove dead code
• Simplify returning statements
• Use interfaces types for parameters/fields/variables where it is straightforward to migrate
• Make visibility stricter where it is possible
• Check logging to use parametrised logging
• Removing unnecessary keywords (e.g.: static)
• Some code part could be simplified by using Java 8 features

I think this is crucial step as this class already contains 15000+ lines of code which is screaming for splitting into more reasonable classes.