[HIVE-11366] Avoid right leaning tree hashCode depth during ExprNodeDescEqualityWrapper HashMaps

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.0.0, 1.1.0, 1.1.1, 1.2.0
• Fix Version/s: 1.3.0, 2.0.0
• Component/s: Logical Optimizer

Release Note

HIVE-11366: Avoid right leaning tree hashCode depth in ExprNodeDescEqualityWrapper hashmaps (Gopal V, reviewed by Ashutosh Chauhan)

• Assignee: Gopal Vijayaraghavan
• Reporter: Gopal Vijayaraghavan
• Created: 24/Jul/15 04:22
• Updated: 16/Feb/16 23:53
• Resolved: 25/Aug/15 21:37

Description

For a large sequence of AND clauses, the precedence order results in a deep unbalanced tree.

(AND A (AND B (AND C (AND D (AND E)....)

which could result in a hashcode for the top-level expression traversing deep.

Issue Links

• is part of: HIVE-11315 Compilation performance issues for large queries