Erik W.

Independent backend and database engineering practice, serving clients on geo-information systems and contributing to open-source PostgreSQL.

• Optimized PostgreSQL procedures and SQL statements in a production geospatial information system, improving runtime performance.
• Upgraded PostgreSQL from version 12 to 16 and migrated production servers from Ubuntu 20.04 to 24.04.
• Migrated the application stack from Python 3.9 to 3.12 and ported legacy modules to a new database model.
• Extended a Flask web application with maintenance-window management and automated email notifications for scheduled downtime.
• Contributed fixes and code reviews to the open-source PostgreSQL project across documentation, psql, libxml2 integration, and PL/Tcl.
• Built pgcov, a tool for reporting PL/pgSQL code coverage, and implemented a materialized-view feature slated for an upcoming PostgreSQL release.

Omexom Hochspannung, part of VINCI Energies, builds and maintains high-voltage transmission infrastructure for the power grids of Germany, Austria, and Italy.

• Designed and implemented PostGIS-backed geographic information systems for planning and constructing high-voltage power lines across the German grid.
• Built data models that enabled direct database access through QGIS as the primary user interface.
• Developed WebGIS modules using Python and React, deployed via Docker on on-premises servers for users without direct database access.
• Engineered a Flask web application for user and project access management, including TOTP-based two-factor authentication and QR-code device synchronization.
• Designed a PostgreSQL backup process using Barman for point-in-time recovery and optimized production PostgreSQL clusters.
• Established the team’s development process using Azure DevOps for CI, Sqitch for versioned database migrations, and Docker for reproducible environments.

gm technology partners is a German software consultancy delivering custom enterprise software for business-critical processes across industries.

• Built a modular Java web application for managing goods flow in food retail, delivering modules for baking schedules, volume planning, and advertising campaigns.
• Served as the technical project lead for these modules, handling requirements analysis and effort estimation.
• Optimized inefficient ORM-generated SQL by replacing it with hand-written queries, developing a strong reputation for tuning complex queries.
• Rebuilt an unmaintainable legacy deposit-refund backend using Spring Boot, using JMH benchmarks of the existing system as a performance baseline.
• Added integration tests to a legacy backend that previously had no test coverage.
• Automated deployments to store servers using Azure DevOps pipelines and Ansible, and upgraded store databases from PostgreSQL 9.2 to 12.