Aleksandr Schlag

I engineer data systems that stay fast, reliable and understandable under pressure — from schema and SQL to distributed storage and production operations.

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01 / Profile

Data, engineered end to end.

More than a decade working where database internals, backend engineering and operations meet.

I design and evolve data systems that remain fast, reliable and understandable as products grow. My work covers the full lifecycle: data modelling, complex SQL, performance engineering, migrations, resilience and production troubleshooting.

I help teams make deliberate storage decisions, remove bottlenecks and reduce operational risk. That means looking beyond an isolated query or technology — into workload patterns, application behaviour, failure modes and the people who must run the system after launch.

Comfortable close to both the engine and the application layer, I work across Linux, automation and systems programming to turn demanding data workloads into maintainable engineering.

02 / Expertise

Deep database craft.

Architecture is more than choosing a database. It is understanding how data behaves, how systems fail and where performance is actually won.

[ 01 ]

Data modelling & architecture

Relational modelling, normalization and intentional denormalization
OLTP and OLAP workload design
Indexes, partitioning and schema evolution
Transactional boundaries and consistency models
Polyglot persistence and technology selection

[ 02 ]

SQL & performance engineering

Advanced SQL, CTEs, window functions and analytics
Execution plans and optimizer behaviour
Statistics, cardinality and index strategy
Lock contention and transaction isolation
Workload profiling and capacity planning

[ 03 ]

Reliability & operations

Replication, backup, restore and recovery planning
High availability and failover patterns
Metrics, logging and production observability
Incident investigation and root-cause analysis
Data integrity, security and safe automation

[ 04 ]

Distributed & non-relational systems

Key-value, wide-column and column-oriented models
Consistency and availability trade-offs
Partition keys, sharding and horizontal scale
Caching, TTL design and hot-key mitigation
High-throughput ingestion and analytics

03 / Stack

Tools chosen by workload.

Broad enough to compare paradigms. Deepest where schemas, SQL and database behaviour shape the system.

01 Relational core

02 Analytical

03 Distributed / NoSQL

04 Engineering

04 / Collaboration

How I can help.

Focused engineering support for systems where data correctness, performance and operational confidence matter.

Architecture

Storage selection, data boundaries and scalable designs grounded in real workloads.

Performance

Query-plan analysis, indexing, workload profiling and targeted bottleneck removal.

Modernization

Pragmatic migration and schema-evolution plans with risk and downtime kept visible.

Reliability

Replication, recovery, observability and failure-mode reviews for production systems.

Incident response

Structured diagnosis of slowdowns, contention and unexpected database behaviour.

Backend engineering

Data-layer implementation and automation in Python, Go, C/C++ and TypeScript.

05 / Contact

Let’s build something resilient.

Open to ambitious database, backend and data-platform work. Based in Bremen, authorized to work in the EU and most interested in fully remote collaboration.

Start a conversation

Email: shlag@tutanota.de
Phone: +49 1575 5830217
Base: Bremen, Germany
Status: EU work authorization
Mode: Fully remote preferred