[LOG4J2-1575] (GC) Store Configuration Properties in List instead of Map to prevent creating temporary iterators

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.6.2
• Fix Version/s: 2.7
• Component/s: Lookups
• Epic Link: GC-free
• Assignee: Remko Popma
• Reporter: Remko Popma
• Created: 11/Sep/16 12:13
• Updated: 11/Sep/16 17:13
• Resolved: 11/Sep/16 17:10

Description

Currently the Configuration stores Property values in a Map, where the key is the Property, and the value is a Boolean specifying whether the value contains a "${", meaning it requires a string substitution.

This is not a problem in itself, but if the configuration contains properties, the Map is iterated over for each event, creating a number of temporary objects.

I propose to store the boolean value in the Property class itself (to be initialized in the constructor). This allows the Configuration to store Property values in an immutable List, which can be iterated over without creating temporary objects.

Issue Links

• supercedes: LOG4J2-1282 Make RingBufferLogEvent::mergePropertiesIntoContextMap allocation-free if possible