High Memory Utilization in LogWatcher of the Due to Unmanaged StringBuilder

[JanakaPushpakumara]

Description

Hi Team,

We have identified a high memory utilization issue in the LogWatcher class [1] in the diagnostic-tool [2]. The StringBuilder used to accumulate log data is not being managed properly, leading to excessive memory usage. This issue was detected through a heap dump analysis using Eclipse MAT, which pointed to a large byte[] instance retained by the StringBuilder.

[1] https://github.com/wso2/runtime-diagnostic-tool/blob/c70186279d8cf9cba3055d690f8d53ab1df4a600/src/main/java/org/wso2/diagnostics/watchers/logwatcher/LogWatcher.java
[2] https://apim.docs.wso2.com/en/4.3.0/troubleshooting/utilizing-runtime-diagnostic-tool/

Thanks,
Janaka.

Steps to Reproduce

1. Run the wso2am 4.3.0 with the LogWatcher class active.
2. Monitor memory usage of the diagnostic-tool over time.
3. Observe the high memory consumption and potential memory leak.

Version

4.3.0

Environment Details (with versions)

No response

[npamudika]

This is fixed in the master branch with wso2/runtime-diagnostic-tool#12

[npamudika]

Upgraded the diagnostic tool version in APIM master brach with wso2/product-apim#13646