[IMPALA-10971] Data cache metrics count error when LIRS is enabled

• Type: Bug
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: Impala 4.0.0
• Fix Version/s: Impala 4.3.0
• Component/s: Backend
• Target Version: Impala 4.3.0
• Epic Color: ghx-label-12
• Assignee: Joe McDonnell
• Reporter: Zihao Ye
• Created: 18/Oct/21 06:30
• Updated: 02/Jun/23 22:41
• Resolved: 02/Jun/23 22:41

Description

When LIRS is enabled, impala-server.io-mgr.remote-data-cache-total-bytes may give a wrong value because of INSTANT EVICTIONS. When INSTANT EVICTIONS occur, the total bytes decreases due to EvictedEntry, and no corresponding increase due to failure of insert, so the total bytes becomes smaller and smaller, or even negative.