[HIVE-19813] SessionState.start don't have to be synchronized

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 3.1.0, 4.0.0-alpha-1
• Target Version/s: 3.1.0
• Hadoop Flags: Reviewed
• Assignee: Daniel Dai
• Reporter: Daniel Dai
• Created: 06/Jun/18 06:58
• Updated: 21/Oct/22 06:59
• Resolved: 12/Jun/18 06:39

Description

This is introduced in HIVE-14690. However, only check-set block needs to be synchronized, not the whole block. The method will start Tez AM, which is a long operation. Make the method synchronized will serialize session start thus slow down hs2.