Message-ID: <gh-pgjdbc-pgjdbc-3089@github.com>
From: "embuc (@embuc)" <noreply+embuc@github.com>
To: "pgjdbc/pgjdbc" <noreply+pgjdbc-pgjdbc@github.com>
Date: Tue, 09 Jan 2024 13:56:41 +0000
Subject: [pgjdbc/pgjdbc] issue #3089: Metaspace Memory leak: Thread.inheritedAccessControlContext
List-Id: <gh-pgjdbc-pgjdbc.github.com>
X-GitHub-Author-Id: 1480007
X-GitHub-Author-Login: embuc
X-GitHub-Issue: 3089
X-GitHub-Repo: pgjdbc/pgjdbc
X-GitHub-State: closed
X-GitHub-Type: issue
X-GitHub-Url: https://github.com/pgjdbc/pgjdbc/issues/3089
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**Describe the issue**
After update to driver version > 42.6.0 (tested also both released version up to latest released 42.7.1) we started to notice memory leaks connected to re-deploys of web-apps in Apache Tomcat (ver 9.0.80). I inspected heap dumps and found the instances of org.postgresql.util.LazyCleaner retained in Metaspace i.e. with path to GC roots with excluded phantom/weak/soft/etc references. Regression seem to have happened with release of 42.6.0 version. Downgraded to 42.5.4 - after excessive testing - no leaks in Metaspace and everything was released correctly. Perhaps this has to do something with [fix 2817](https://github.com/pgjdbc/pgjdbc/pull/2817) and/or [fix 2847 ](https://github.com/pgjdbc/pgjdbc/pull/2847)? I didn't have time to investigate more but it should be hopefully enough to point the experts in right direction.    

**Driver Version?** 
42.6.0
**Java Version?**
17
**OS Version?**
Ubuntu 22.04
**PostgreSQL Version?**
14
**To Reproduce**
Steps to reproduce the behaviour:
Re-deploy .war files in Apache Tomcat. 
**Expected behaviour**
GC should be able to clean Metaspace when classes are unloaded (as with deploy).
And what actually happens:
Old Classloader is bound with reference from LazyCleaner thus preventing GC to remove it. 

**Logs**
If possible PostgreSQL logs surrounding the occurrence of the issue (N/A)