[MYFACES-4186] [perf] concurrency issue in _ComponentAttributesMap

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.0.24, 2.1.18, 2.2.12, 2.3.0-beta
• Fix Version/s: 2.0.25, 2.1.19, 2.2.13, 2.3.0
• Assignee: Bill Lucy
• Reporter: Bill Lucy
• Created: 09/Jan/18 14:27
• Updated: 25/Jun/20 17:51
• Resolved: 12/Jan/18 19:37

Description

We've hit a performance issue with the property descriptor map in _ComponentAttributesMap. Driving a heavy load to an application, we can see threads spending a lot of time in this area:

...
(entered lock: java/util/Collections$SynchronizedMap@0x000000000000000, entry count:1)
at javax/faces/component/_ComponentAttributesMap.getPropertyDescriptor(_ComponentAttributesMap.java:394(Compiled Code))
at javax/faces/component/_ComponentAttributesMap.containsKey(_ComponentAttributesMap.java:165(Compiled Code))
at javax/faces/component/UIComponent.isCompositeComponent(UIComponent.java:239(Compiled Code))
...

In this case, replacing the HashMap used by _propertyDescriptorMap with a ConcurrentHashMap gives us much better performance. Since we can use a ConcurrentHashMap here, there shouldn't be any performance hit in the normal case.

Related: https://issues.apache.org/jira/browse/MYFACES-3216