Freelancer: Senior DBA & Data Engineer ? SQL Server, PostgreSQL, Oracle | HA/DR, Replication, ETL/SSIS | 20+ yrs Banking/Insurance

Freiberufler / Selbstst�ndiger

Verf�gbar ab: 13.09.2026

Verf�gbar zu: 100%

davon vor Ort: 10%

Top-Skills

Oracle DBA

MS SQL Datenbankadministration

PostgreSQL

Oracle

MySQL

MariaDB

MongoDB

Redis

T-SQL

MS SQL Server Integration Services

MS SQL Server Reporting Services

PowerShell

Python

Ansible

MS Azure SQL Database

AWS

ServiceNow

Sprachen

Italian

English

French

Spanish

Czech

Russian

Einsatzorte

L�nder

Deutschland, Schweiz, �sterreich

Remote-Arbeit

nicht m�glich

Projekte

4 months

2026-06 - now

Core insurance data platform, multi-server SQL Server estate

Senior SQL Server DBA / Database Engineer

Rolle

Senior SQL Server DBA / Database Engineer

Projektinhalte

T-SQL development and performance tuning on the core insurance data platform: stored procedures, reporting queries and batch routines against high-volume transactional schemas.
Execution-plan driven query optimization ? index redesign, join-strategy correction, removal of non-SARGable predicates and implicit conversions.
Administration of Always On Availability Groups, IPU (In-Place Upgrade) management, replication topologies and SQL Agent automation across a multi-server estate.
Operational automation with PowerShell and Ansible playbooks; incident and service-request handling via ServiceNow, environment access via Citrix.
Production incident diagnosis: blocking chains, deadlock graphs, long-running transactions and wait-statistics analysis, with permanent query-level fixes rather than restarts.
Security hardening and audit remediation across the SQL Server estate.

Kunde

NN Group

Einsatzort

Prague

2019 - today: Multi-Platform DBA

Place of Work: Prague & EU

Role: Senior T-SQL Developer

Customer: on request

Tasks:

Develop and refactor large T-SQL codebases: stored procedures, metadata-driven dynamic SQL generators, batch DML routines and reporting layers, against agreed runtime targets.
Rewrote a heavily-used batch UPDATE over a multi-million-row document-line table into a chunked, index-aligned set-based routine, eliminating lock escalation and collapsing the maintenance window.
Cross-platform SQL Server / PostgreSQL administration: streaming replication / HA, backup & PITR, tuning and migrations to Azure; automation via shell & Python, monitoring with Grafana.
MySQL/MariaDB administration (replication, backup/restore, tuning), CouchDB and Redis (caching, session storage); Informix (11.70?14.10) HDR/RSS, OnBar/ONTape backups and tuning.
Merge and transactional replication troubleshooting at scale: metadata retention and cleanup, subscription reinitialization storms, concurrency limits, orphaned-metadata recovery.
Data modelling for new modules and schema refactoring on live systems, coordinating with application developers and business owners.

2020 - 2026: Multi-brand retail ERP platform

Role: SQL Server Developer & DBA / Reliability Engineer

Customer: Visilab (EssilorLuxottica Group), Geneva / Prague

Tasks:

Multi-brand retail ERP platform (OneSuite) across several country entities, SQL Server with heavy reporting and integration load.
Owner of the T-SQL layer: stored procedures, views and functions backing the ERP and its reporting, including complex dynamic SQL for configurable, multi-tenant queries.
Managed a heterogeneous estate ? SQL Server, PostgreSQL, MySQL/MariaDB, MongoDB and Redis ? on virtual, physical, cloud and container (Kubernetes/OpenShift) infrastructure, with Tier 2/3 support under SLA.
Performance tuning of the transactional workload with Query Store based regression tracking; resolved recurring blocking and deadlock incidents through isolation-level changes and query rewrites.
Designed and maintained the merge-replication topology synchronizing store-level and central data, including retention, conflict and reinitialization policy.
Delivered SSIS ETL and SSRS reporting; migrated SSRS 2016 ? 2022 and ran Always On rolling upgrades (SQL 2016 ? 2022) without service interruption.
Led a security hardening and audit programme: permission-model rework, least-privilege refactoring of application accounts, Kerberos and linked-server delegation.

2019 - 2019: SQL Server and MongoDB administration

Role: DBA / Data Engineer

Customer: SOCAR Trading, Geneva

Tasks:

SQL Server and MongoDB administration, T-SQL development for commodity-trading data flows
ETL pipelines, HA/DR, migrations to Azure and AWS, SAP HANA integration, Kafka streaming for near-real-time pipelines

2018 - 2018: SQL Server and Oracle 12c development

Role: DBA / SQL Developer

Customer: SwissCaution, Switzerland

Tasks:

MS Dynamics CRM integration
SAP data synchronization
ETL development
HA/DR management
cloud-migration tasks

2012 - 2018: Backend development for global trade-statistics platforms

Role: Database Expert (SQL Server / Oracle)

Customer: United Nations ? International Trade Centre, Geneva

Tasks:

Backend development for global trade-statistics platforms:
- complex analytical T-SQL and PL/SQL over very large datasets under strict correctness and reconciliation requirements.
Tuning of long-running analytical queries, index and partitioning strategy, SSIS ETL, Data Guard HA/DR and data-quality frameworks over multi-terabyte data warehouses.

2010 - 2012: data-warehouse design

Customer: Swissport, Geneva

Tasks:

ETL pipelines and BI dashboards (Tableau, QlikView) for cargo logistics

Skills:

Tableau, QlikView

2008 - 2010: financial data warehousing

Customer: BSI Bank, Lugano

Tasks:

financial data warehousing, ETL, SAS BI and regulatory data processing in private banking

2006 - 2008: OBIEE / Oracle OLAP & OLTP development

Customer: CODIX France, Sophia Antipolis

Tasks:

OBIEE / Oracle OLAP & OLTP development, financial consolidation systems and data-quality.

1998 - 2006: enterprise data-warehouse development

Customer: Telecom Italia, Rome

Tasks:

CRM analytics
ETL pipelines
churn & campaign management
reporting

Aus- und Weiterbildung

Information Technology

MSc

University of Renfrew (USA)

Certification:

PRINCE2 Foundation

Position

Senior Database Administrator (DBA) - Multi-Platform
Database Reliability Engineer

Kompetenzen

Top-Skills

Oracle DBA MS SQL Datenbankadministration PostgreSQL Oracle MySQL MariaDB MongoDB Redis T-SQL MS SQL Server Integration Services MS SQL Server Reporting Services PowerShell Python Ansible MS Azure SQL Database AWS ServiceNow

Produkte / Standards / Erfahrungen / Methoden

Profile

Senior Database Administrator / Database Reliability Engineer with 20+ years on mission-critical OLTP and BI platforms across insurance, banking, telecom, commodity trading, retail and international organizations. Primary expertise in Microsoft SQL Server and PostgreSQL, with hands-on experience across MySQL/MariaDB, MongoDB, Oracle, Redis and Kafka. My technical core is T-SQL: writing and refactoring complex, performance-oriented queries, reading execution plans down to the operator level, turning slow, lock-heavy workloads into predictable ones. Alongside this I run production database estates end to end - high availability and disaster recovery, replication, backup/restore and recovery, security and hardening, automation (PowerShell, Ansible, Python) and observability (Grafana, Prometheus, ELK). I invoice EU-wide through my own Czech company, with no agency intermediary.

CORE TECHNICAL SKILLS

SQL Server (primary):

SQL Server 2008R2?2022
Always On Availability Groups
Failover Clustering
merge & transactional replication
backup & recovery models
restore / point-in-time recovery
SQL Server Agent
index & statistics management
security, roles and permissions

Advanced T-SQL development:

Stored procedures and complex dynamic SQL
window functions
CTEs and recursive CTEs
MERGE
APPLY
table-valued functions and parameters
temporal tables
JSON/XML
set-based rewrites of cursor/RBAR logic
transaction control and error handling (TRY/CATCH, XACT_ABORT, savepoints)

Query optimization & performance tuning:

Actual vs. estimated plan analysis, physical join operators (nested loops / merge / hash)
index seek vs. scan, key lookups and spools, cardinality estimation, parameter sniffing (RECOMPILE, OPTIMIZE FOR, plan guides)
Query Store regression hunting, wait statistics, Extended Events, tempdb contention

Indexing, locking & concurrency:

Clustered/nonclustered and covering index design, filtered indexes, columnstore
partitioning and partition elimination, lock escalation, blocking chains, deadlock graph analysis, isolation levels incl. RCSI/SI, index consolidation and cleanup

PostgreSQL:

Installation, configuration & upgrades
streaming replication & HA, logical replication, backup/restore (pg_dump, pg_basebackup, PITR)
vacuum/autovacuum tuning, indexing & query optimization (EXPLAIN/ANALYZE)
roles, privileges and extensions

Data engineering / ETL / BI:

SSIS, SSAS, SSRS
dimensional/star-schema and 3NF OLTP modelling
ETL/ELT pipelines
data warehousing, data-quality and reconciliation logic
Tableau
SAP HANA
SAS BI
Power BI

Automation & DevOps:

PowerShell
Ansible (playbooks)
Python
Bash
dbatools
Git / Azure DevOps
CI/CD
VM blueprints / baselines

Containers & cloud:

Kubernetes / OpenShift (databases on containers)
Azure (SQL Database, VM migrations, consolidation)
AWS (incl. RDS)

Observability & ITSM:

Grafana
Prometheus
ELK
native SQL Server tooling (Extended Events, DMVs, Query Store, execution plans, wait-stats)
ServiceNow, Citrix

Security & compliance:

Security hardening
access-control review
auditability, encryption, pseudonymization/anonymization
data minimization, retention and controlled deletion

Betriebssysteme

MySQL/MariaDB

MongoDB

CouchDB

Oracle

Redis

Kafka

Informix

DB2

Linux

Unix shell

Windows Server

Einsatzorte

L�nder

Deutschland, Schweiz, �sterreich

Remote-Arbeit

nicht m�glich

Projekte

4 months

2026-06 - now

Core insurance data platform, multi-server SQL Server estate

Senior SQL Server DBA / Database Engineer

Rolle

Senior SQL Server DBA / Database Engineer

Projektinhalte

T-SQL development and performance tuning on the core insurance data platform: stored procedures, reporting queries and batch routines against high-volume transactional schemas.
Execution-plan driven query optimization ? index redesign, join-strategy correction, removal of non-SARGable predicates and implicit conversions.
Administration of Always On Availability Groups, IPU (In-Place Upgrade) management, replication topologies and SQL Agent automation across a multi-server estate.
Operational automation with PowerShell and Ansible playbooks; incident and service-request handling via ServiceNow, environment access via Citrix.
Production incident diagnosis: blocking chains, deadlock graphs, long-running transactions and wait-statistics analysis, with permanent query-level fixes rather than restarts.
Security hardening and audit remediation across the SQL Server estate.

Kunde

NN Group

Einsatzort

Prague

2019 - today: Multi-Platform DBA

Place of Work: Prague & EU

Role: Senior T-SQL Developer

Customer: on request

Tasks:

Develop and refactor large T-SQL codebases: stored procedures, metadata-driven dynamic SQL generators, batch DML routines and reporting layers, against agreed runtime targets.
Rewrote a heavily-used batch UPDATE over a multi-million-row document-line table into a chunked, index-aligned set-based routine, eliminating lock escalation and collapsing the maintenance window.
Cross-platform SQL Server / PostgreSQL administration: streaming replication / HA, backup & PITR, tuning and migrations to Azure; automation via shell & Python, monitoring with Grafana.
MySQL/MariaDB administration (replication, backup/restore, tuning), CouchDB and Redis (caching, session storage); Informix (11.70?14.10) HDR/RSS, OnBar/ONTape backups and tuning.
Merge and transactional replication troubleshooting at scale: metadata retention and cleanup, subscription reinitialization storms, concurrency limits, orphaned-metadata recovery.
Data modelling for new modules and schema refactoring on live systems, coordinating with application developers and business owners.

2020 - 2026: Multi-brand retail ERP platform

Role: SQL Server Developer & DBA / Reliability Engineer

Customer: Visilab (EssilorLuxottica Group), Geneva / Prague

Tasks:

Multi-brand retail ERP platform (OneSuite) across several country entities, SQL Server with heavy reporting and integration load.
Owner of the T-SQL layer: stored procedures, views and functions backing the ERP and its reporting, including complex dynamic SQL for configurable, multi-tenant queries.
Managed a heterogeneous estate ? SQL Server, PostgreSQL, MySQL/MariaDB, MongoDB and Redis ? on virtual, physical, cloud and container (Kubernetes/OpenShift) infrastructure, with Tier 2/3 support under SLA.
Performance tuning of the transactional workload with Query Store based regression tracking; resolved recurring blocking and deadlock incidents through isolation-level changes and query rewrites.
Designed and maintained the merge-replication topology synchronizing store-level and central data, including retention, conflict and reinitialization policy.
Delivered SSIS ETL and SSRS reporting; migrated SSRS 2016 ? 2022 and ran Always On rolling upgrades (SQL 2016 ? 2022) without service interruption.
Led a security hardening and audit programme: permission-model rework, least-privilege refactoring of application accounts, Kerberos and linked-server delegation.

2019 - 2019: SQL Server and MongoDB administration

Role: DBA / Data Engineer

Customer: SOCAR Trading, Geneva

Tasks:

SQL Server and MongoDB administration, T-SQL development for commodity-trading data flows
ETL pipelines, HA/DR, migrations to Azure and AWS, SAP HANA integration, Kafka streaming for near-real-time pipelines

2018 - 2018: SQL Server and Oracle 12c development

Role: DBA / SQL Developer

Customer: SwissCaution, Switzerland

Tasks:

MS Dynamics CRM integration
SAP data synchronization
ETL development
HA/DR management
cloud-migration tasks

2012 - 2018: Backend development for global trade-statistics platforms

Role: Database Expert (SQL Server / Oracle)

Customer: United Nations ? International Trade Centre, Geneva

Tasks:

Backend development for global trade-statistics platforms:
- complex analytical T-SQL and PL/SQL over very large datasets under strict correctness and reconciliation requirements.
Tuning of long-running analytical queries, index and partitioning strategy, SSIS ETL, Data Guard HA/DR and data-quality frameworks over multi-terabyte data warehouses.

2010 - 2012: data-warehouse design

Customer: Swissport, Geneva

Tasks:

ETL pipelines and BI dashboards (Tableau, QlikView) for cargo logistics

Skills:

Tableau, QlikView

2008 - 2010: financial data warehousing

Customer: BSI Bank, Lugano

Tasks:

financial data warehousing, ETL, SAS BI and regulatory data processing in private banking

2006 - 2008: OBIEE / Oracle OLAP & OLTP development

Customer: CODIX France, Sophia Antipolis

Tasks:

OBIEE / Oracle OLAP & OLTP development, financial consolidation systems and data-quality.

1998 - 2006: enterprise data-warehouse development

Customer: Telecom Italia, Rome

Tasks:

CRM analytics
ETL pipelines
churn & campaign management
reporting

Aus- und Weiterbildung

Information Technology

MSc

University of Renfrew (USA)

Certification:

PRINCE2 Foundation

Position

Senior Database Administrator (DBA) - Multi-Platform
Database Reliability Engineer

Kompetenzen

Top-Skills

Produkte / Standards / Erfahrungen / Methoden

Profile

CORE TECHNICAL SKILLS

SQL Server (primary):

SQL Server 2008R2?2022
Always On Availability Groups
Failover Clustering
merge & transactional replication
backup & recovery models
restore / point-in-time recovery
SQL Server Agent
index & statistics management
security, roles and permissions

Advanced T-SQL development:

Stored procedures and complex dynamic SQL
window functions
CTEs and recursive CTEs
MERGE
APPLY
table-valued functions and parameters
temporal tables
JSON/XML
set-based rewrites of cursor/RBAR logic
transaction control and error handling (TRY/CATCH, XACT_ABORT, savepoints)

Query optimization & performance tuning:

Actual vs. estimated plan analysis, physical join operators (nested loops / merge / hash)
index seek vs. scan, key lookups and spools, cardinality estimation, parameter sniffing (RECOMPILE, OPTIMIZE FOR, plan guides)
Query Store regression hunting, wait statistics, Extended Events, tempdb contention

Indexing, locking & concurrency:

Clustered/nonclustered and covering index design, filtered indexes, columnstore
partitioning and partition elimination, lock escalation, blocking chains, deadlock graph analysis, isolation levels incl. RCSI/SI, index consolidation and cleanup

PostgreSQL:

Installation, configuration & upgrades
streaming replication & HA, logical replication, backup/restore (pg_dump, pg_basebackup, PITR)
vacuum/autovacuum tuning, indexing & query optimization (EXPLAIN/ANALYZE)
roles, privileges and extensions

Data engineering / ETL / BI:

SSIS, SSAS, SSRS
dimensional/star-schema and 3NF OLTP modelling
ETL/ELT pipelines
data warehousing, data-quality and reconciliation logic
Tableau
SAP HANA
SAS BI
Power BI

Automation & DevOps:

PowerShell
Ansible (playbooks)
Python
Bash
dbatools
Git / Azure DevOps
CI/CD
VM blueprints / baselines

Containers & cloud:

Kubernetes / OpenShift (databases on containers)
Azure (SQL Database, VM migrations, consolidation)
AWS (incl. RDS)

Observability & ITSM:

Grafana
Prometheus
ELK
native SQL Server tooling (Extended Events, DMVs, Query Store, execution plans, wait-stats)
ServiceNow, Citrix

Security & compliance:

Security hardening
access-control review
auditability, encryption, pseudonymization/anonymization
data minimization, retention and controlled deletion

Betriebssysteme

MySQL/MariaDB

MongoDB

CouchDB

Oracle

Redis

Kafka

Informix

DB2

Linux

Unix shell

Windows Server

Vertrauen Sie auf Randstad

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Fragen?

Rufen Sie uns an +49 89 500316-300 oder schreiben Sie uns:

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Einsatzorte

Einsatzorte

Projekte

Projekte

Core insurance data platform, multi-server SQL Server estate

Aus- und Weiterbildung

Aus- und Weiterbildung

Position

Position

Kompetenzen

Kompetenzen

Top-Skills

Produkte / Standards / Erfahrungen / Methoden

Betriebssysteme

Einsatzorte

Einsatzorte

Projekte

Projekte

Core insurance data platform, multi-server SQL Server estate

Aus- und Weiterbildung

Aus- und Weiterbildung

Position

Position

Kompetenzen

Kompetenzen

Top-Skills

Produkte / Standards / Erfahrungen / Methoden

Betriebssysteme

Vertrauen Sie auf Randstad

Fragen?

Rufen Sie uns an +49 89 500316-300 oder schreiben Sie uns:

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