This post explores how threads in Kotlin enter a BLOCKED state when they cannot acquire a lock held by another thread. A sample program demonstrates this scenario with 10 threads attempting to access a synchronized method, causing 9 to be blocked. It also discusses diagnosing BLOCKED threads through manual and automated approaches.
The article explains how to simulate and troubleshoot CPU spikes in Kotlin by creating a program with six threads in an infinite loop. It discusses manual and automated approaches to diagnose CPU spikes, detailing how to capture and analyze thread dumps using the yCrash tool for effective root cause analysis of performance issues.
The application connecting to the Oracle RAC cluster experienced performance issues due to resource constraints, causing unresponsiveness. Troubleshooting artifacts were collected and analyzed using yCrash, revealing that 46% of threads were blocked waiting for database responses. After escalating to the DBA, resource adjustments resolved the slowdown, restoring normal application function.
Apache PDFBox is an open-source library for handling PDF documents in Java. A recent deadlock issue was identified in the library, which occurs when two threads are blocked, waiting for resources held by each other. The problem was diagnosed using a thread dump, and a ticket was filed, resulting in a prompt fix by the PDFBox team.
This post discusses deadlock in multi-threaded applications, specifically in Kotlin. It defines deadlock and provides a practical example using trains on a single track. A sample Kotlin program illustrates how deadlock occurs between two threads. Troubleshooting deadlock involves capturing thread dumps and analyzing them with tools like yCrash for clearer insight.
The post discusses troubleshooting intermittent HTTP 502 Bad Gateway errors in an application running on AWS Elastic Beanstalk. The errors were traced to the Tomcat server, which was terminated due to insufficient RAM (1GB). Upgrading to a 2GB RAM EC2 instance resolved the issue, eliminating the errors.
The post discusses c1 and c2 compiler threads in Java, which optimize application performance but may lead to high CPU consumption. It explains the differences between client and server JIT compilers, default thread counts, and provides solutions for managing high CPU usage, including JVM arguments to adjust compilation levels and thread counts.
On October 11, 2021, GCeasy experienced an outage due to HTTP 504 errors caused by inefficiencies in a new SQL query from a recent deployment. AWS CloudWatch monitored CPU and database connection spikes, while yCrash identified the problematic code. Commenting out the SQL query restored application performance.
This article on chaos engineering demonstrates how to simulate a CPU spike to 100% using an infinite loop in a Java program with multiple threads. It discusses monitoring CPU consumption using the UNIX tool 'top' and suggests manual and automated root cause analysis methods, highlighting the yCrash tool's effectiveness in identifying the source of the issue.