About
Krzysztof Książek
Independent database consultant. I help software teams and agencies investigate MySQL, MariaDB and Aurora MySQL performance and availability questions, and hand over findings their engineers can act on.
What I help with
Most engagements start with a specific problem: a query or workload that has become slow, a locking problem that keeps coming back, or a planned change that needs an independent view.
My background combines production database operations, high-availability architecture, performance investigations, and technical support leadership. I look at the database, the operational context around it, and what your team can realistically change.
How I work
- Share the context, the problem and the evidence already available.
- We agree the investigation, deliverables, fee and schedule before starting.
- I investigate personally and separate supported findings from what still needs testing.
- Your engineers receive recommendations and validation steps they can act on, with a technical handover.
Selected experience
Roles below distinguish employment from independent consulting.
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Database Reliability Engineer
Sporty Group
Employment
- 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.
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Owner · Independent consultant
DB-Ex
Own business
- Independent database consulting and architecture for high-availability systems, including MySQL/MariaDB, Galera, and InnoDB Cluster.
- 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.
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Head of Support
Severalnines
Employment
- 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.
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Senior Support Engineer
Severalnines
Employment
- 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.
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Operational DBA
PalominoDB / Blackbird
Employment
- MySQL operations, performance tuning, and architecture improvements for multiple clients.
- High-availability solutions and on-call cover for critical production environments.
- Capacity planning, database health checks, and performance optimization reviews.
Writing and talks
46 technical articles on this site, including 12 hands-on lab write-ups such as a nine-part MySQL backup verification series.
- Percona Live Europe: MySQL load-balancers speaker interview Percona's interview about my talk on MaxScale, ProxySQL, HAProxy, MySQL Router and nginx, while at Severalnines.
- Severalnines webinar: MySQL and MariaDB load balancing with ProxySQL A joint session with ProxySQL creator René Cannaò, including my demonstration of a ProxySQL setup in ClusterControl.
- Severalnines webinar replay and Q&A: ProxySQL, HAProxy and MaxScale Published material from my work as a Senior Support Engineer, covering deployment, management and audience questions.
These are references to my professional work, not DB-Ex customer endorsements. Historical technical guidance should be checked against current product versions.
“Krzysztof is one of the most reliable, efficient and capable database administrators I have met. There has not been a task that he has not achieved, typically with results that exceeded expectations. His ability to work within teams, and independently, and to create a sense of trust and security with clients is a huge asset to the organization. I am quite grateful to have him on our team.”
Background
Beyond the consulting focus above, I have worked with PostgreSQL, Redis, MongoDB and ClickHouse, which helps when a question crosses system boundaries.
Education: Cracow University of Technology (Politechnika Krakowska im. Tadeusza Kościuszki), 2000 — 2005.
Have a database question worth investigating?
Describe the system, the problem, and what you need to find out. We can then establish whether a focused engagement is the right next step.