DB-Ex

About Us

Krzysztof Ksiazek

Senior MySQL & MariaDB DBRE · High Availability Architect & Consultant

My name is Krzysztof Książek and I have been a database administrator since 2007. I have been working with different technologies, including PostgreSQL, Redis, MongoDB, and ClickHouse, but my main area of expertise is MySQL.

With over 14 years of experience in MySQL and MariaDB consulting, I specialize in architecture design for high availability environments built on these datastores. I provide professional services related to HA design, performance reviews, and assistance in delivering successful proofs of concept. My mission is to help customers design and maintain highly available database environments based on open source databases.

I like MySQL for its ease of use and the variety of solutions around it: MySQL NDB Cluster, Galera Cluster, InnoDB Cluster, asynchronous and semi-synchronous replication, Vitess, ProxySQL, MaxScale. Those solutions can handle quite some problems thrown at them. Even if your problem is too complex for MySQL to deal with, what I like is how easy you can export data from MySQL to other databases like ClickHouse or big-data systems.

I very much hope that I will be able to help you in your challenges and that together we will make your MySQL implementation successful.

Experience

  1. Apr 2025 — Present

    Database Reliability Engineer

    Sporty Group

    Remote

    • Day-to-day operations for a large fleet of 700+ Amazon Aurora clusters and MongoDB Atlas deployments, keeping availability, performance, and stability across multi-database environments.
    • Designed and implemented a new database sharding system to improve scalability and data distribution across relational and document databases.
    • Performed major Aurora version upgrades across 30+ clusters with minimal downtime and risk.
    • Performance debugging and optimization for MongoDB Atlas using Query Profiler, Performance Advisor, and Real-Time Performance Panel.
    • Improved alerting and incident management by integrating Jira-based maintenance scheduling, cutting alert noise and mean time to resolution.
    • Worked with development teams on complex schema changes and query optimizations in large-scale Aurora and MongoDB Atlas environments.

  2. Jun 2012 — Present

    Owner · Independent consultant

    DB-Ex

    Remote

    • Independent database consulting and architecture for MySQL, MariaDB, Galera Cluster, and InnoDB Cluster for clients worldwide.
    • Performance audits and optimization: schema design, query performance, and configuration tuning for high-traffic systems.
    • High-availability architectures including replication topologies, failover, and disaster recovery.
    • End-to-end engagements from audits and proofs of concept through production deployments and ongoing operational support.

  3. Jul 2019 — Mar 2025

    Head of Support

    Severalnines

    Remote

    • Led a global technical support team, driving customer satisfaction and retention through proactive service and technical excellence.
    • Designed and deployed high-availability solutions (MySQL, MariaDB, Galera, ProxySQL, MaxScale, MongoDB) for enterprise clients.
    • Supported sales with pre-sales consulting and proof-of-concept work.
    • Created webinars, blogs, and best-practice guides; delivered performance optimization consulting for complex production environments.

  4. Feb 2015 — Jul 2019

    Senior Support Engineer

    Severalnines

    Remote

    • Mission-critical MySQL and MariaDB support and consulting for enterprise customers worldwide.
    • Technical blogs, webinars, and training materials on high availability, replication, load balancing, and performance tuning.
    • Spoke at Percona Live Europe on MySQL load balancers (MaxScale, ProxySQL, HAProxy, MySQL Router, nginx).
    • Built deep expertise in ClusterControl and database automation while handling complex customer escalations.

  5. Jul 2012 — Jan 2015

    Operational DBA

    PalominoDB / Blackbird

    Kraków, Poland

    • MySQL operations, performance tuning, and architecture improvements for multiple clients.
    • High-availability solutions and 24/7 on-call for critical production environments.
    • Capacity planning, database health checks, and performance optimization reviews.