Elasticsearch version 8.9.1

High Memory Pressure due to a GC JVM setting change

This version of Elasticsearch is bundled with JDK 20. In JDK 20 Preventive GC is disabled by default. This may lead to increased memory pressure and an increased number of CircuitBreakerExceptions when retrieving large documents under some load patterns. (issue: #99592)

If this change affects your use of Elasticsearch, consider re-enabling the previous behaviour by adding the JVM arguments -XX:+UnlockDiagnosticVMOptions -XX:+G1UsePreventiveGC (reference: JDK 20 release notes). It is important to note that this workaround is temporary and works only with JDK 20, which is bundled with Elasticsearch up to version 8.10.2 inclusive. Successive versions are bundling JDK 21+, where this setting has been removed. Specifying those JVM arguments will prevent the JVM (and therefore Elasticsearch Nodes) from starting.