[LOG4J2-2269] Memory leaking of replacement parameters in case of enableThreadlocals=true

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 3.0.0
• Component/s: Core
• Assignee: Remko Popma
• Reporter: Dmitry Konstantinov
• Created: 23/Feb/18 18:08
• Updated: 05/Feb/19 20:28
• Resolved: 23/Apr/18 18:53

Description

Use case:
1) I have a thread pool with quite large number of threads (around 100)
2) Threads from the pool sometimes process some heavy objects. Threads are not actively writing into logs (so, a thread may process a task and does not log any message).
3) As a part of processing for some objects in some non-frequently used branch a thread logged a message with heavy replacement parameters (parameterized log message is used).

In this case such heavy replacement parameters are not garbage collected until another message will not written within the same thread because thread-local ReusableParameterizedMessage and MutableLogEvent objects keep references to the replacement parameters.

Is it possible to cleanup such references when a message is released (for example as a part of org.apache.logging.log4j.message.ReusableMessageFactory#release and org.apache.logging.log4j.core.impl.ReusableLogEventFactory#release) to avoid such kind of leaks?

Issue Links

• links to: GitHub Pull Request #165