[RATIS-2017] CheckAndEvictCache must be done in writeLock

• Type: Bug
• Status: Resolved
• Priority: Critical
• Resolution: Fixed
• Affects Version/s: 3.0.0
• Fix Version/s: 3.1.0
• Component/s: server
• Assignee: Duong
• Reporter: Duong
• Created: 27/Jan/24 01:32
• Updated: 27/Jan/24 21:10
• Resolved: 27/Jan/24 21:10

Description

RATIS-1893 moved checkAndEvictCache to a separate thread. 

This opens a condition race between evictCache and normal log operations like get/put. 

Before RATIS-1893, checkAndEvictCache was called from appendEntryImpl and safe under a writeLock().

 

I noticed this error because there are get/put operations intervene with the EntryCache eviction during testing zero-copy:

void clear() {
  map.values().forEach(ReferenceCountedObject::release);
  map.clear();
  size.set(0);
} 

Issue Links

• is caused by: RATIS-1893 In SegmentedRaftLogCache, start a daemon thread to checkAndEvictCache
• links to: GitHub Pull Request #1031