This article details a step‑by‑step investigation of a container whose memory usage spiked to 99% due to large objects being allocated to the old generation under G1GC, explains the root cause, demonstrates reproducible tests with JVM flags and monitoring tools, and provides practical mitigation strategies.
This article documents a step‑by‑step investigation of a high TP99 caused by frequent Full GC in a Java service, describing the diagnostic mindset, tools used, GC trigger conditions, object promotion mechanisms, the impact of AdaptiveSizePolicy and Metaspace, and the concrete configuration and code changes that eliminated the issue.
This article documents a month‑long JVM garbage‑collection tuning process that reduced daily FullGC occurrences from over 40 to less than one per ten days by adjusting heap parameters, fixing memory leaks, and tuning Metaspace, while providing detailed analysis, code snippets, and performance graphs.
A June 15 Full GC alert in a Spring Data Elasticsearch service led to a deep investigation using jstat, jmap, VisualVM, and OQL, revealing massive class loading from ES PO packages caused by per‑request ElasticsearchRestTemplate instances, which exhausted metaspace and triggered repeated garbage collections.
This article examines a real‑world case where a serverless instance’s automatic scaling was instantly overwhelmed, causing high CPU usage, frequent Full GC and JVM crashes, and then demonstrates how Sentinel’s system‑level rules can mitigate the overload and improve cold‑start performance.
The article analyzes a serverless scaling failure where newly added instances suffered high CPU and frequent Full GC leading to JVM crashes, reproduces the issue under load, and demonstrates how Sentinel's CPU‑based circuit‑breaker rule mitigates the problem across cold and hot start scenarios.
This article dives deep into the OpenJDK G1 FullGC implementation, explaining its architecture, trigger conditions, preparation steps, and the four‑phase collection process while comparing single‑threaded and multi‑threaded implementations in JDK 8 and JDK 11, and highlighting code paths that can cause long GC pauses.
The report analyzes recurring morning Full GC alerts in a Java service, identifies a Groovy‑driven scheduled task as the root cause through JVM parameter review, log inspection, and memory profiling, and proposes concrete fixes such as reusing a single GroovyShell instance and clearing its classloader cache.
This article documents a month-long JVM garbage‑collection tuning effort on a 2‑core, 4 GB server cluster, detailing initial problems with frequent FullGC, successive configuration adjustments, memory‑leak investigations, and the final optimizations that cut FullGC occurrences and significantly improved overall throughput.
