Position: Java Software Engineer
Category: Java
English level: fluent
Years of experience: 5


September 2018 – February 2023, Software Engineer at CERN, Geneva, Switzerland

Working as a Software Engineer in a team responsible for the CERN-wide Accelerator Data Logging Service (NXCALS). We provide mission-critical products to allow a large user community to capture, persist, extract and analyze data from the CERN particle accelerators.

• Developing and maintaining large-scale resilient distributed systems based on a Big Data stack with microservices architecture that is responsible for the effective storing and extraction of almost 2PB of data.
• Developing/extending and testing the data ETL pipelines, data ingestion and extraction APIs. Achieved 3x increased performance for heavy data extractions by introducing key-salting techniques.
• Developing/enhancing and commissioning the distributed system responsible for the migration of 1PB of data for 2.5 million signals from the main legacy system. Handling more than 300 various conflicts and unique cases to achieve data integrity and smooth decommissioning. Analyzing data transformation algorithms in the previous data acquisition chain and developing an adaptation mechanism to move to the new system.
• Performing and coordinating various system and software upgrades. Integrating other in-house projects and services. Enhancing continuous integration and deployment mechanisms.
• Handling end-user requests, providing technical solutions and assisting in system integration. Participating in support rota activities.
• Successfully collaborating and coordinating with other teams to provide highly available user-friendly products and services.

Tech stack: Java, Spring, Python, Hadoop, HBase, Spark, Kafka, PL/SQL, Gradle, GitLab, Jenkins CI/CD, Ansible, Prometheus, Grafana, ELK, Oracle Database, Liquibase, JUnit, OpenStack.

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January 2018 – August 2018, Full Stack Software Developer at IBM (Internship), Kyiv, Ukraine

• Designing and implementing new functionality for the internal project for time tracking and work planning.
• Upgrading project configurations to newer standards.
• Making a training/presentation about new technologies.

Tech stack: Java, Spring, Hibernate, DB2, JavaScript, jQuery.