[LOG4J2-2212] Unnecessary contention in CopyOnWriteSortedArrayThreadContextMap

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.10.0
• Fix Version/s: 2.11.0
• Assignee: Gary Gregory
• Reporter: Daniel Feist
• Created: 23/Jan/18 14:25
• Updated: 24/Jan/18 14:51
• Resolved: 23/Jan/18 21:33

Description

The following method retrieves the value of a system property for each and every map that is created.  While maps are cached/reused where possible via thread local this method is still used a lot in runtime.

protected StringMap createStringMap() {
  return new SortedArrayStringMap(PropertiesUtil.getProperties().getIntegerPropertyPROPERTY_NAME_INITIAL_CAPACITY, DEFAULT_INITIAL_CAPACITY));
}

Under concurrency, this introduces unnecessary contention due to java.util.Properties monitor in HashTable.contains when retrieving system property, as seen below.

 

 

Issue Links

• is related to: LOG4J2-2213 Unnecessary contention in GarbageFreeSortedArrayThreadContextMap
• is related to: LOG4J2-2214 Unnecessary contention in DefaultThreadContextMap.