Eugene is available for hire
Hire EugeneEugene Bereznuk
Verified Expert in Engineering
SQL Developer
Geraardsbergen, Belgium
Toptal member since July 5, 2021
Bio
Eugene is a SQL Server expert with 25+ years of experience in Microsoft SQL Server, from version 6.5 to the most recent standalone and cloud-based versions. He's worked for both small businesses and global enterprises such as Kone, DHL, and Sony. Eugene has taught courses in "Data and Database Architecture" and "The Technical Side of SQL Server" to classes with up to 10 students. He's also an expert in Power BI, Microsoft Access, and Red Gate software.
Portfolio
Tourisoft Sàrl
Microsoft SQL Server, SQL, SQL Server 2014, SQL Server 2017, SQL Server DBA...
Eurostar
Azure SQL Databases, Database Administration (DBA), Data, Database Development...
Objecutive, Inc
SQL, Microsoft SQL Server, Performance Tuning, Optimization...
Experience
- SQL Server DBA - 20 years
- Database Performance - 20 years
- Database Design - 20 years
- Transact-SQL (T-SQL) - 20 years
- Microsoft SQL Server - 20 years
- Database Administration (DBA) - 20 years
- SQL Performance - 20 years
- Microsoft Power BI - 5 years
Preferred Environment
SQL, Azure SQL Databases, SQL Server DBA, Microsoft SQL Server, Azure SQL, Microsoft Power BI
The most amazing...
...moment I've had was an SQL query that used to take 4-5 hours to complete, but suddenly ran in 14 seconds, all thanks to corrected indexes and a query hint.
Work Experience
MS SQL Server Expert
2025 - 2025
Tourisoft Sàrl
- Migrated production instances of local cluster SQL Server 2014 to version 2019 in Azure VM.
- Conducted an audit and analysis of production databases. Tackled performance bottlenecks and problem identification and solving.
- Handled database architecture and design refactoring to improve scalability.
Technologies: Microsoft SQL Server, SQL, SQL Server 2014, SQL Server 2017, SQL Server DBA, SQL Server 2019, Azure SQL, Database Architecture, Microsoft Power BI, SQL Stored Procedures, Transact-SQL (T-SQL), Dashboard Design, Power BI Desktop, SQL Server, SQL DBA, SQL Backups, Azure SQL Managed Instance, Database Performance, Performance Tuning, Database Optimization, Azure
SQL Server Consultant
2023 - 2024
Eurostar
- Conducted an analysis and audit of existing data import, ETL processes, and data correlation.
- Conducted a functional analysis of existing databases and data model alterations.
- Refactored the code, improved performance, and implemented testing and production.
Technologies: Azure SQL Databases, Database Administration (DBA), Data, Database Development, Data Modeling, JSON, SQL Server 2019, SQL, SQL Server DBA, Transact-SQL (T-SQL), Performance Optimization, SQL Performance, Databases, Indexing, Azure, Query Optimization, Microsoft 365, Database Management, Data Analysis, Database Modeling, SQL Stored Procedures, Database Schema Design, VPN, DAX, ETL, Reporting, Google Apps Script, SQL Server, SQL DBA, SQL Backups, Azure SQL Managed Instance, Database Performance, Performance Tuning, Database Optimization
MS SQL Performance Tuning Consultant
2023 - 2024
Objecutive, Inc
- Identified several scopes (landscapes) of performance improvements, starting with global Windows/SQL Server settings and options, via generic data model improvements up to individual processes and databases.
- Identified the most critical bottlenecks across all databases.
- Developed the proof of concept by refactoring the code of many procedures, views, and functions and adjusting the index system.
Technologies: SQL, Microsoft SQL Server, Performance Tuning, Optimization, Database Optimization, Data Migration, SQL Server 2019, SQL Server DBA, SQL Server Profiler, Database Development, Transact-SQL (T-SQL), Performance Optimization, SQL Performance, Databases, Indexing, Azure, Query Optimization, Microsoft 365, Data Engineering, Azure SQL, Database Management, Data Visualization, Data Cleaning, SQL Stored Procedures, Database Normalization, Database Schema Design, VPN, DAX, Key Performance Indicators (KPIs), ETL, Power BI Desktop, Reporting, SQL Server, SQL DBA, SQL Backups, Database Architecture, Azure SQL Managed Instance, Database Performance
Database Engineer
2022 - 2024
Sandhills Global
- Designed target SQL Server database for Currency V.1 project. The primary objectives were to achieve high performance under heavy concurrent load and maintain stability.
- Performed data migration from multiple legacy databases into the new target database. Created a reporting database using Azure replication and elastic queries.
- Maintained good performance and reliability for over two years in a constantly changing production environment.
Technologies: SQL, Microsoft SQL Server, Database Administration (DBA), Transact-SQL (T-SQL), Azure, Apache Airflow, Performance Optimization, Python, SQL Performance, Databases, Indexing, Microsoft Access, Query Optimization, Google Sheets, Microsoft 365, Data Engineering, Microsoft Power BI, Azure SQL, Database Management, Data Analysis, Excel Macros, Amazon Web Services (AWS), Azure Data Factory (ADF), Database Modeling, Data Cleaning, Excel 365, SQL Stored Procedures, Database Normalization, Database Schema Design, VPN, Dashboard Design, Key Performance Indicators (KPIs), ETL, Power BI Desktop, Reporting, Google Apps Script, Google Forms, MySQL, SQL Server, SQL DBA, SQL Backups, Database Architecture, Azure SQL Managed Instance, Database Performance, Performance Tuning, Database Optimization
SQL Server Specialist
2022 - 2022
Euroclear
- Handled the auditing of existing SQL Server databases and data flows.
- Identified performance bottlenecks and potential risks.
- Implementation of system versioning technologies instead of homemade history tables for a data audit.
Technologies: Azure SQL Databases, SQL Server 2016, Optimization, Performance Tuning, Database Optimization, JSON, Excel VBA, Visual Basic, SQL, Database Replication, SQL Server Profiler, Transact-SQL (T-SQL), Performance Optimization, SQL Performance, Databases, Indexing, Microsoft Access, Azure, Microsoft 365, Database Administration (DBA), Finance, Data Visualization, Dashboards, Azure Data Factory (ADF), SQL Stored Procedures, Database Normalization, Microsoft Power BI, Reporting, SQL Server, SQL DBA, SQL Backups, Azure SQL Managed Instance, Database Performance
SQL Server DBA | Performance Expert
2021 - 2022
VISMA
- Merged two multi-billion rows tables. The total downtime required was one hour.
- Identified non-used indexes and implemented numerous changes to the index system, which significantly improved performance in certain cases.
- Straight-lined backup processes and tweaked Lungren's procedures for full and differential backups.
Technologies: SQL Server 2016, Data, SQL, SQL Performance, Database Performance, Microsoft DBA, Optimization, Performance Tuning, Database Optimization, JSON, Microsoft Excel, Excel VBA, Data Migration, SQL Server Clusters, SQL Server DBA, Database Replication, SQL Server Profiler, Transact-SQL (T-SQL), Performance Optimization, Databases, Indexing, Business Intelligence (BI), Query Optimization, Microsoft 365, Database Administration (DBA), Data Engineering, Microsoft Power BI, Azure SQL, Finance, Excel 365, SQL Stored Procedures, Database Normalization, VPN, ETL, Power BI Desktop, Reporting, Google Apps Script, SQL Server, SQL DBA, SQL Backups, Database Architecture, Azure SQL Managed Instance, Azure
SQL Server Specialist | Support Coordinator
2020 - 2021
Shurgard
- Administered the SQL Server administration managing various environments, stored procedures, functions, jobs, indexing, partitioning, replication, mirroring, resource management, performance analysis, and improvements.
- Handled massive data migrations, including sources like multiple Oracle databases, flat files, etc. Did a post-migration data audit.
- Designed, developed, and implemented a data import and integration engine.
Technologies: SQL Server 2016, Microsoft SQL Server, Database Optimization, JSON, Data Migration, SQL Server Clusters, SQL, SQL Server DBA, Database Replication, SQL Server Profiler, Database Development, Transact-SQL (T-SQL), SQL Performance, Databases, Indexing, Azure, Google Sheets, Microsoft 365, Database Administration (DBA), Finance, Database Management, Data Visualization, Dashboards, Database Modeling, Data Cleaning, SQL Stored Procedures, Database Normalization, Database Schema Design, VPN, Dashboard Design, ETL, Power BI Desktop, Reporting, Google Forms, MySQL, SQL Server, SQL DBA, SQL Backups, Azure SQL Managed Instance, Database Performance
Global SQL Server Database Administrator (DBA) | Senior Data Expert
2013 - 2020
Kone
- Performed SQL Server administration, including but not limited to stored procedures, functions, jobs, indexing, partitioning, replication, mirroring, resource management, performance analysis, and improvements; also monitored the SQL Server.
- Developed, designed, and architected data warehouses which included the design, planning, and implementation of a range of environments design (production, acceptance, development); also helped to migrate platforms.
- Contributed to software architecture primarily the data flow and persistence.
Technologies: SQL Server 2008 R2, SQL Server Integration Services (SSIS), SQL Server 2016, Azure SQL Databases, Redgate SQL Toolbelt, Database Design, Database Performance, Microsoft SQL Server, Optimization, Performance Tuning, Database Optimization, Microsoft Excel, Excel VBA, Data Migration, Visual Basic for Applications (VBA), Visual Basic, SQL Server Clusters, SQL, Spreadsheets, Database Mirroring, Database Replication, SQL Server Profiler, Database Development, Transact-SQL (T-SQL), Performance Optimization, Data Architecture, SQL Performance, Databases, Indexing, Business Intelligence (BI), Query Optimization, Google Sheets, Database Administration (DBA), Data Engineering, Microsoft Power BI, Database Management, Dashboards, Data Analysis, Excel Macros, Database Modeling, Data Cleaning, Excel 365, SQL Stored Procedures, Database Normalization, Database Schema Design, ETL, Reporting, MySQL, SQL Server, SQL DBA, SQL Backups, Database Architecture
SQL Server Engineer
2012 - 2012
DHL International
- Analyzed the existing enterprise datastore and BI data warehouses and designed, modeled, and prepared the migration to another infrastructure; also implemented the actual migration.
- Evaluated the existing SSIS ETL structure and analyzed the existing OLTP processes.
- Optimized, maintained, and administered the corporate databases and data warehouses.
Technologies: SQL Server 2008 R2, SQL Server 2012, Windows PowerShell, Microsoft SQL Server, Microsoft Excel, Excel VBA, Data Migration, Visual Basic for Applications (VBA), Visual Basic, SQL, SQL Server DBA, Database Mirroring, Database Replication, Database Development, Transact-SQL (T-SQL), Performance Optimization, SQL Performance, Databases, Indexing, Business Intelligence (BI), Query Optimization, Database Management, Dashboards, Excel Macros, Data Cleaning, SQL Stored Procedures, Database Normalization, Reporting, SQL Server, SQL DBA, SQL Backups
Data Architect | SQL Engineer
2009 - 2011
Belgacom (now Proximus)
- Architected and physically installed the SQL Server clustered environment and new and existing data centers.
- Audited and optimized existing data centers and databases, including massive performance improvements.
- Designed and implemented the Microsoft BI environment which included the development and administration of the data and Infrastructure migration and consolidation design, planning, and implementation.
Technologies: SQL Server 2005, SQL Server 2008 R2, SQL Server Integration Services (SSIS), ER/Studio Data Architecture, Windows PowerShell, Database Design, Data Architecture, Microsoft SQL Server, Visual Basic for Applications (VBA), Visual Basic, SQL, Spreadsheets, Transact-SQL (T-SQL), SQL Performance, DTS, Databases, Indexing, Database Administration (DBA), SQL Stored Procedures, Business Intelligence (BI), SQL Server, SQL DBA
Database Engineer | SQL Server Performance Specialist | Database Administrator (DBA)
2008 - 2009
Sony Electronics
- Analyzed the existing SAN/Cluster SQL Server instances which included the preparation and implementation of the migration from 2000 to 2005 versions.
- Created a new data warehouse and designed and developed ETL processes.
- Solved performance issues and tracked and enhanced critical processes.
Technologies: SQL Server 2000, SQL Server 2005, SQL Server 2008 R2, SQL Server Integration Services (SSIS), Redgate SQL Compare, ER/Studio Data Architecture, Database Design, Database Performance, Microsoft SQL Server, SQL Server DBA, Optimization, Data Migration, Visual Basic for Applications (VBA), SQL, Spreadsheets, SQL Performance, Databases, Indexing, Database Administration (DBA), SQL Stored Procedures, Database Normalization, SQL DBA
Experience
Migration of Chinese Corporate Databases
When I started on this project, I found old corporate databases in multiple formats, including SQL Server 2000 to 2008, Oracle, etc. The Chinese encoding was different everywhere (including outdated and archaic encodings) and needed to be unified to UTF-8. The approximate volume of data was close to 2.5-3TB. The target platform was SQL Server 2016 cluster, and the allowed downtime was 12 hours. After downtime, every hour of data unavailability would cost the company millions.
To save time, data streams were processed consequently for encoding, quality and integrity. A portion of data was preloaded into staging tables.
The project was finished successfully, with the indexes and replication created well within the downtime frame.
To save time, data streams were processed consequently for encoding, quality and integrity. A portion of data was preloaded into staging tables.
The project was finished successfully, with the indexes and replication created well within the downtime frame.
Data Export to S3
It was necessary to regularly export data (with preliminary processing) to a cloud-landing site. The source data was scattered among multiple databases and data warehouses, often requiring dozens of complicated joins.
We created numerous stored procedures which provided processed and formatted data. A fully dynamic SSIS package accepted a stored procedure name as one of the parameters, executed it, exported the results into a CSV file, and placed them on target landing site—all fully automatically, without any intervention.
We created numerous stored procedures which provided processed and formatted data. A fully dynamic SSIS package accepted a stored procedure name as one of the parameters, executed it, exported the results into a CSV file, and placed them on target landing site—all fully automatically, without any intervention.
Performance Improvement at a Global Corporation
A global multinational corporation had a portion of its technical, online, and archive data on a vast array of SQL Servers all around the globe. This data was used in reporting as well as exporting to SAP and other systems.
The performance was deteriorating as the data volume and traffic increased.
The preliminary stage included isolating the most problematic queries, triggers, functions, and stored procedures. Also, about 50% of the queries were generated automatically by third-party software and could not be altered.
To solve this, we performed a global audit of the index system which resulted in removing excessive and unused indexes with changing the majority of the existing indexes to newly created ones.
Where possible, function calls were removed from clauses, triggers replaced with external code, and isolation levels and degrees of parallelism were reviewed.
We chose to implement SQL Server Resource Governor to separate system resources between different applications and users. As a result performance problems disappeared completely while guaranteeing future scalability and expandability.
The performance was deteriorating as the data volume and traffic increased.
The preliminary stage included isolating the most problematic queries, triggers, functions, and stored procedures. Also, about 50% of the queries were generated automatically by third-party software and could not be altered.
To solve this, we performed a global audit of the index system which resulted in removing excessive and unused indexes with changing the majority of the existing indexes to newly created ones.
Where possible, function calls were removed from clauses, triggers replaced with external code, and isolation levels and degrees of parallelism were reviewed.
We chose to implement SQL Server Resource Governor to separate system resources between different applications and users. As a result performance problems disappeared completely while guaranteeing future scalability and expandability.
Skills
Tools
Redgate SQL Compare, Microsoft Access, Microsoft Power BI, SQL Server Profiler, Microsoft Excel, Google Sheets, VPN, Power BI Desktop, Google Forms, DTS, Spreadsheets, Apache Airflow
Languages
Transact-SQL (T-SQL), Visual Basic for Applications (VBA), Visual Basic 6 (VB6), SQL, Stored Procedure, Excel VBA, Visual Basic, Google Apps Script, Python
Paradigms
Database Design, ETL, Business Intelligence (BI), Database Development
Platforms
Windows, Azure, Amazon Web Services (AWS)
Storage
SQL Server DBA, Redgate SQL Toolbelt, Database Performance, SQL Performance, Data Definition Languages (DDL), SQL Server 2008 R2, SQL Server Integration Services (SSIS), SQL Server 2016, SQL Server 2012, SQL Server 2005, SQL Server 2000, SQL Server 2019, Microsoft SQL Server, DB, SQL Stored Procedures, Databases, SQL Triggers, Database Migration, Database Replication, Relational Databases, Database Mirroring, SQL Architecture, Database Administration (DBA), Microsoft DBA, Azure SQL, Database Management, Database Modeling, Database Architecture, Azure SQL Databases, JSON, ER/Studio Data Architecture, SQL Server 2014, SQL Server 2017, MySQL
Frameworks
Windows PowerShell
Other
Data Architecture, Data Warehouse Design, Data, Indexing, Relational Database Design, Data Modeling, Key Performance Indicators (KPIs), Optimization, Performance Tuning, Database Optimization, Data Migration, SQL Server Clusters, Performance Optimization, Query Optimization, Microsoft 365, Data Engineering, Data Visualization, Dashboards, Excel Macros, Data Cleaning, Database Normalization, Database Schema Design, DAX, Reporting, SQL Server, SQL DBA, SQL Backups, Azure SQL Managed Instance, Data Warehousing, Finance, Data Analysis, Azure Data Factory (ADF), Excel 365, Dashboard Design, Consolidation, Encoding
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