ActiveRecord anti-caching implementation causes out-of-memory error in JRuby

[nbekirov]

Recently, our production web environments began failing due to OOM (Out of Memory) errors. Upon analyzing the heap dumps, we noticed a large number of 33-character strings, all prefixed with a t. It turns out that this issue was caused by our use of with_advisory_lock. This method utilizes random strings generated by WithAdvisoryLock::Base#unique_column_name as aliases for the lock acquisition result column names, which are then stored in the Java::ArjdbcUtil::StringCache.

While this might be considered an issue in activerecord or activerecord-jdbc-adapter, it would be preferable to use a more gentle strategy to "Prevent AR from caching results improperly". Any thoughts?

Environment:

• rails 6.1.7
• jruby 9.3.15.0 (2.6.8) 2024-06-26 28bea01242 OpenJDK 64-Bit Server VM 25.312-b07 on 1.8.0_312-b07 +jit [arm64-darwin]

[1] https://github.com/jruby/activerecord-jdbc-adapter/blob/master/src/java/arjdbc/jdbc/RubyJdbcConnection.java [2] https://github.com/jruby/activerecord-jdbc-adapter/blob/master/src/java/arjdbc/util/StringCache.java