Dmitry is available for hire
Hire DmitryDmitry Kozlov
Verified Expert in Engineering
Big Data Architect and Developer
Toronto, ON, Canada
Toptal member since February 24, 2021
Bio
Dmitry is a senior big data architect with 16+ years of experience in data warehousing, BI, ETL, analytics, and the cloud. He's led teams in the delivery of 24 projects in the industries of finance, insurance, telecommunications, government, education, mining, manufacturing, and retail. Dmitry thrives in high-paced environments, has demonstrated the ability to lead effectively, manage, and support teams, and has consulted on several projects as a BI, data warehouse, and big data expert.
Portfolio
CD Newco LLC
Data Architecture, Amazon Web Services (AWS), Analytics, Data Pipelines...
Hendrick Autoguard - Main
Data Governance, Data Engineering, Data Warehouse Design, SQL Stored Procedures...
Hendrick Autoguard - Main
Data Engineering, Snowflake, Architecture, Automation
Experience
- Data Architecture - 20 years
- Business Intelligence (BI) - 20 years
- SQL - 20 years
- Data Engineering - 18 years
- Data Warehouse Design - 16 years
- ETL - 16 years
- Tableau - 10 years
- Big Data - 5 years
Preferred Environment
SQL, ETL, Data Architecture, Big Data, Business Intelligence (BI), Data Warehousing, Tableau, Team Leadership, Snowflake, Data Analysis
The most amazing...
...and challenging project I've done was building an ETL framework for a small startup that was crucial to the company's growth.
Work Experience
Lead Analytics Engineer / Data Architect (Greenfield Project)
2026 - PRESENT
CD Newco LLC
- Built a Customer Cube that created a reporting view for a harmonized customer.
- Created Snowflake data warehouse using the Medalion Architecture for 12 data sources. ETL pipelines developed in Talend.
- Created Tableau dashboards to replace Salesforce reports.
Technologies: Data Architecture, Amazon Web Services (AWS), Analytics, Data Pipelines, Data Visualization, Data Modeling, SQL, Data Governance, Board Reporting, Customer Data, ETL, ELT, Talend Stitch, Tableau, Snowflake
Data Governance SME
2025 - PRESENT
Hendrick Autoguard - Main
- Led data warehouse migration from MS SQL to Snowflake.
- Developed an ETL framework using Snowflake stored procedures.
- Automated source data load using metadata dictionaries.
Technologies: Data Governance, Data Engineering, Data Warehouse Design, SQL Stored Procedures, Data Strategy, Data Governance, Data Architecture, Data Quality, Data Analysis
DBA Snowflake Engineer
2026 - 2026
Hendrick Autoguard - Main
- Developed an automated framework on Snowflake and dbt using the Medallion architecture.
- Implemented a metadata-driven automated bronze layer data pipeline.
- Created an automated data quality and reconciliation solution for incoming data.
Technologies: Data Engineering, Snowflake, Architecture, Automation
Senior Snowflake Data Engineer
2026 - 2026
Proven Winners North America, LLC - Main
- Led successful MDM initiative for customers and brokers.
- Integrated Snowflake - Salesforce for accounts and orders based on the golden record.
- Supported Salesforce migration using Snowflake data warehouse.
Technologies: Snowflake, Medallion Architecture, Role-based Access Control (RBAC), Data Warehousing, Data Engineering, ETL, Data Lakehouse, iPaaS, Python, Data Build Tool (dbt), Salesforce, Talend, Enterprise Resource Planning (ERP), Inventory Management, Picas, Master Data Management (MDM)
PostgreSQL Search Engine Expert
2025 - 2025
Go Playfully Inc
- Analyzed the client's app performance issues using Python benchmark scripts.
- Isolated network and dataset structure issues and ruled out database configuration as the cause.
- Provided short and long-term recommendations for PostgreSQL implementation on Google Cloud.
Technologies: Google Cloud Platform (GCP), PostgreSQL, SQL, PostgreSQL 9, Search, Vector Search, Python, SQL Performance, GIS
Snowflake/Sigma Data Analyst
2024 - 2025
Howl Technologies Inc.
- Developed numerous Sigma Computing dashboards on Snowflake.
- Automated monthly invoicing for key brand partners.
- Designed a new data warehouse platform on Snowflake.
- Cut Snowflake's daily cost by 60% across an organization. Improved Sigma Computing dashboard performance.
Technologies: Python, Data Engineering, SQL, Query Optimization, Data Analysis, Snowflake, Amazon Web Services (AWS), Sigma Computing Data Visualization, Sigma.js, Business Intelligence (BI), SQL Stored Procedures, Looker, Reporting, Fivetran, Data Governance, Business Intelligence (BI), Data Reporting, Data Quality, Data Analysis
Senior Solutions Architect | Migration Lead
2024 - 2025
Blue Cross Blue Shield
- Led a team of developers and QA analysts in a source system migration project for a Fitbit rewards project.
- Designed a solution to replace a major source system for a key insurance benefit application.
- Performed reverse engineering and data analysis for an existing Oracle application.
Technologies: Data Architecture, Oracle, Data Migration, Solution Design, Wearables, Query Optimization, Data Warehouse Design, SQL Stored Procedures, Data Strategy, Database Administration (DBA), Backup & Recovery, Database Backups, Solution Architecture, Data Governance, Data Architecture, Data Quality, Data Analysis
Senior Data Engineer
2023 - 2024
Orbital Kitchens
- Developed the first version of the client's corporate dashboard.
- Created a forecast for Superbowl 2024 demand and analyzed the execution.
- Integrated the customer historical and incremental order data.
Technologies: Data Visualization, ETL, Data Engineering, Modeling, SQL, Tableau, Databases, Snowflake, Data Warehouse Design, Business Intelligence (BI), GIS, Data Governance, Business Intelligence (BI), Data Architecture, Data Reporting, Data Quality, Data Analysis
Data Engineer III
2023 - 2024
Gartner - Engineering
- Migrated Oracle data structure and software packages to PostgreSQL.
- Conducted extensive performance tuning on both Oracle and PostgreSQL.
- Used Python Streamlit to create custom reporting solutions.
Technologies: PL/SQL, Oracle, SQL, PostgreSQL, Amazon Web Services (AWS), Python, Terraform, CI/CD Pipelines, Scaled Agile Framework (SAFe), Performance Tuning, Dynamic SQL, Query Optimization, Big Data, SQL Stored Procedures, Database Administration (DBA), Backup & Recovery, Database Backups
Data Analyst Engineer
2022 - 2022
Bentkey Services, LLC
- Performed statistical analysis for Recurly subscription data integrated with Snowflake data warehouse.
- Provided a marketing budget channel attribution analysis on Facebook and YouTube.
- Developed video playback metadata analysis and a campaign effectiveness analysis.
Technologies: SQL, Data Analysis, Statistics, Snowflake, Event-driven Architecture, Domo, Recurly, Business Analysis, Data Analytics, Fivetran, Data Quality, Data Analysis
Cloud Data Engineer
2022 - 2022
Vivid Machines Inc.
- Developed complex Tableau dashboards for apple growers.
- Designed a data model for a machine learning output.
- Automated ETL pipelines to support the dashboards.
Technologies: SQL, Amazon Web Services (AWS), Data Pipelines, Data Engineering, Python, ETL, Data Warehousing, Data Architecture, Data Lakes, Databases, Data Modeling, Data Analysis, APIs, Tableau, PostgreSQL, Event-driven Architecture, Data Visualization, Google Cloud SQL, Google Cloud Platform (GCP), Machine Learning, Business Intelligence (BI), Reporting, GIS, Business Intelligence (BI), Data Reporting
Senior Data Engineer
2022 - 2022
SIG - Main
- Created a tool to integrate data from Hadoop data and Oracle data marts.
- Helped business users create custom requests from two sources.
- Provided training to business users on how to use a new tool.
Technologies: SQL, Oracle, Oracle PL/SQL, Python, Hadoop, Spark SQL, ETL, PL/SQL, Data Warehousing, Big Data, Apache Hive, Data Pipelines, Performance Tuning, Dynamic SQL, Query Optimization, Database Administration (DBA), Backup & Recovery, Database Backups
Senior Data Architect
2021 - 2022
Canadian Apartment Properties REIT
- Supported the enterprise architecture team on their strategy initiative phase two.
- Designed a data model for several subject areas and created logical and physical data models.
- Integrated several data sources into a corporate data lake.
Technologies: Azure, Azure SQL, Azure Data Factory (ADF), Data Lakes, Data Marts, Kimball Methodology, Data Modeling, Microsoft Power BI, Data Analysis, Data Governance, Transact-SQL (T-SQL), Data Governance, Data Architecture
Data and ETL Architect
2021 - 2021
Haus
- Created an operations tracking data mart on Snowflake. Collected events from a website.
- Created a marketing data mart to track social media spending and channel attribution.
- Developed a Tableau dashboard for management and operations.
Technologies: Snowflake, Tableau, Amazon DynamoDB, Stitch Data, Event-driven Architecture, Data Analysis, Data Analytics, Fivetran, Data Architecture, Data Analysis
Data and ETL Architect
2021 - 2021
Standard Normal
- Designed a data model for energy trading across five major markets.
- Migrated legacy data from an old database to a new database.
- Developed ETL pipelines to load trading data from source systems and provided tools for risk assessment and analytics.
Technologies: Google BigQuery, Google Cloud SQL, PostgreSQL, Microsoft SQL Server, Data Architecture, ETL, Kimball Methodology, Data Analytics, Data Pipelines, Google Cloud Platform (GCP), Transact-SQL (T-SQL), SQL Stored Procedures, Data Quality
Data and ETL Architect
2016 - 2021
Daisy Intelligence
- Developed a fully functional ETL framework that 10 developers used.
- Designed the corporate data architecture for companies in the retail and insurance domains.
- Led a team in onboarding 17 retail and five insurance data warehouses for clients.
- Designed a set of Tableau dashboards to monitor the ETL framework.
- Developed an extensive ETL package and implemented performance tuning.
- Led the prototype development for migrating an on-premise solution to Google Cloud.
Technologies: SQL, Apache Hive, Hadoop, IBM Db2, ETL, Big Data, Data Warehousing, Data Warehouse Design, Tableau, PL/SQL, SQL Stored Procedures, Data Architecture, Databases, PostgreSQL, Data Modeling, Spark SQL, Kimball Methodology, Team Leadership, Data Analysis, Data Visualization, Data Analytics, Data Pipelines, Google BigQuery, Google Cloud SQL, Performance Tuning, Dynamic SQL, Google Cloud Platform (GCP), JavaScript, Machine Learning, Query Optimization, Business Intelligence (BI), BigQuery, Data Strategy, Solution Architecture, Data Governance, Data Product Management, Business Intelligence (BI), Data Architecture, Data Reporting, Data Quality, Data Analysis
BI and Data Architect
2014 - 2016
Bayer Canada
- Designed numerous data marts for Tableau dashboards for executives, account managers, and sales reps.
- Led a team of onshore and offshore ETL and BI developers.
- Addressed database and dashboard performance issues.
Technologies: Tableau, Oracle, PL/SQL, Microsoft SQL Server, ETL, Business Intelligence (BI), PostgreSQL, Databases, Team Leadership, Data Analysis, Data Visualization, JavaScript, Reporting, Business Intelligence (BI), Data Reporting
Senior FATCA Data Architect
2014 - 2016
TD Bank Group
- Designed, from end to end, a solution for different source systems.
- Implemented comprehensive data modeling for a data warehouse and data marts.
- Served as the go-to performance tuning guy and optimized complex queries and stored procedures.
- Reviewed the data architecture, architectural blueprint, and business requirement documents.
Technologies: Oracle 12c, PL/SQL, Erwin, Business Analysis, Solution Design, Data Architecture, Data Pipelines, Google Cloud, Performance Tuning, Database Administration (DBA), Backup & Recovery, Database Backups, Data Governance, Data Architecture, Data Quality, Data Analysis
BI Architect
2014 - 2015
Innovapost
- Created BI semantic layer, metadata, and report definitions for RDP and BOBJ universes.
- Implemented extensive performance tuning of Oracle data mart queries.
- Transformed a local MS Access solution for unaddressed emails to enterprise architecture based on Oracle and the BusinessObjects server.
Technologies: Business Intelligence (BI), SAP BusinessObjects (BO), Tableau, SQL, erwin Data Modeler, Oracle, Data Marts, Kimball Methodology, Data Analysis, Data Visualization, Reporting, Business Intelligence (BI), Data Reporting
Senior Data Architect
2012 - 2014
Intact Financial
- Designed all layers in an enterprise data warehouse (EDW) to acquire a data feed from Guidewire ClaimCenter.
- Ideated and designed all layers in the enterprise data warehouse (EDW) to acquire a data feed from Detica NetReveal.
- Participated in a data warehouse enhancement initiative that replaced multiple data hubs with a data vault.
Technologies: Oracle, SQL, Oracle PL/SQL, Erwin, Data Architecture, Data Vaults, Sybase PowerDesigner, Informatica ETL, ETL, Business Analysis, Kimball Methodology, Data Governance, Data Architecture, Data Analysis
Senior Data Warehouse and BI Solution Designer
2011 - 2013
Rogers Communications
- Took the business/data requirements from the business/data analysts and translated these requirements into information delivery logical designs and technical specifications that the BI designers/developers needed.
- Led the strategy, design, and implementation of solutions in the area of business intelligence and data warehousing.
- Designed project-based data models and added them to BI tools.
Technologies: Oracle, Teradata, Oracle PL/SQL, MicroStrategy, erwin Data Modeler, SQL Stored Procedures, Dynamic SQL, Query Optimization, Solution Architecture, Data Architecture
Senior ETL Developer
2008 - 2010
Bristol West
- Performed a comprehensive data warehouse assessment.
- Designed logical and physical data models for enterprise data warehouses (EDW) and numerous data marts.
- Developed complex mappings and performed extensive SQL tuning and optimization on queries and PL/SQL stored procedures.
- Led and mentored a team and created and utilized best practices documents to elicit the best team performance.
Technologies: Oracle, Data Architecture, SQL, Oracle PL/SQL, Oracle Warehouse Builder (OWB), Oracle Data Integrator (ODI), erwin Data Modeler, Kimball Methodology, Data Pipelines, Performance Tuning, Dynamic SQL, Data Strategy, Database Administration (DBA), Backup & Recovery, Database Backups
Senior Data Warehouse Architect
2008 - 2008
Vale Canada
- Reviewed the existing Vale Canada data warehouse process documentation, development methodologies, data models, and ETL.
- Conducted interviews with the Vale Canada technical staff to understand current data warehouse capabilities and collect future methodology and architecture requirements.
- Participated in workshops to gather information about current data warehouse capabilities, future methodology, and architecture requirements and validate project findings and recommendations.
- Assisted the project manager by making recommendations for methodology, architecture, and other improvements required to close internal audit recommendations.
Technologies: erwin Data Modeler, Microsoft SQL Server, Microsoft Visio, Data Warehousing, Data Warehouse Design, Data Governance, Transact-SQL (T-SQL)
Senior ETL Developer
2006 - 2008
Colleges
- Led a team of ETL developers in the development of an increment 1 data warehouse. Scheduled, assigned, managed, and tracked their work, coordinating resources and task dependencies. Set the technical direction for team members.
- Managed the development, quality assurance, deployment, and initial and daily load processes.
- Developed complex mappings and performed extensive SQL tuning and optimization on queries and PL/SQL stored procedures.
- Performed business analysis, designed data warehouse, and created mapping specifications.
Technologies: Data Warehouse Design, Data Warehousing, ETL, Oracle PL/SQL, Oracle Warehouse Builder (OWB), Oracle Designer, Data Architecture, SQL Stored Procedures, Performance Tuning
Senior Business Analyst
2006 - 2006
Brit
- Designed overall solution requirements for claims and aggregate exposures subject areas as part of the overall BI project.
- Gathered requirements through documentation and customer interviews and analyzed source system data.
- Performed a logical and physical design for the data model for the data warehouse and the data marts.
- Created numerous mapping specifications for ETL processes and composed report specifications.
Technologies: Business Analysis, SQL, erwin Data Modeler, Data Architecture, ETL Specification, Data Governance
Senior ETL Developer
2005 - 2006
TELUS
- Led a team of ETL developers in a project-based camp. Scheduled, assigned, managed, and tracked work. Coordinated resources and task dependencies that set the technical direction for team members.
- Collaborated with a BI team and an architect to develop high-level process designs and entity models and provided training for the support team.
- Designed the ETL solution architecture and data architecture.
- Developed complex mappings and performed extensive SQL tuning and optimization on queries and PL/SQL stored procedures.
Technologies: SQL, Oracle PL/SQL, erwin Data Modeler, Data Architecture, ETL, Unix Shell Scripting, Oracle Warehouse Builder (OWB)
Senior ETL Developer
2005 - 2005
CIBC
- Developed and documented numerous extract, transform, and load PL/SQL packages for different data feeds for the Basel II project, a wholesale credit data warehouse.
- Performed extensive SQL tuning and optimization on queries and PL/SQL stored procedures.
- Collaborated with other team members and managed other subject areas.
Technologies: SQL, Oracle, Oracle PL/SQL, Stored Procedure, ETL, Data Warehousing, Data Warehouse Design
Senior ETL Developer
2004 - 2004
Dynamic Funds
- Developed ETL (extract, transform, load) routines for several data marts.
- Consulted with a team of developers regarding the development of supporting Oracle tables, indexes, views, triggers, packages, procedures, in-line functions, and SQL queries.
- Performed extensive SQL tuning and optimization on views, queries, and PL/SQL stored procedures.
Technologies: SQL, Oracle PL/SQL, Oracle, ETL, SQL Stored Procedures, Unix Shell Scripting, Data Warehouse Design, Data Warehousing
Senior Data Application Developer
2000 - 2004
PdMAIN
- Led and trained a team of developers, solution analysts, and support specialists for the new edition of the sequencing process for numerous implementations on different sites of TDS Automotive.
- Created numerous PL/SQL stored program units (packages, procedures, functions, and triggers) and Oracle Forms and Oracle Reports for different modules of the PdMAIN’s ERP system.
- Developed the complete OLTP data architecture's logical and physical design.
Technologies: SQL, Enterprise Resource Planning (ERP), Oracle PL/SQL, Oracle, Stored Procedure, erwin Data Modeler, Data Architecture, Oracle Forms & Reports, Oracle Application Express (APEX)
Experience
ETL Framework
One of my most challenging yet successful projects was with a small startup that had ambitious goals but lacked the budget for an ETL tool.
The startup's prototype solution stored procedures on IBM Db2. Their data intake was about to grow exponentially. Therefore, they had decided to migrate to a Hive/Hadoop cluster.
To satisfy their evolving needs and utilize their development team's skill set, I designed and developed an end-to-end ETL framework that ran stored procedures like ETL processes in a Hive/Hadoop environment, kept all metadata on a Db2 server, and had Tableau dashboards for operational support.
This framework was able to serve a team of up to ten developers and three support operators. We used it for ETL development for 17 retail and five insurance data warehouses. Later on, we migrated it to a GCP cloud.
The ETL framework was crucial for the company's growth, allowing it to expand development and support operations for at least five years.
The startup's prototype solution stored procedures on IBM Db2. Their data intake was about to grow exponentially. Therefore, they had decided to migrate to a Hive/Hadoop cluster.
To satisfy their evolving needs and utilize their development team's skill set, I designed and developed an end-to-end ETL framework that ran stored procedures like ETL processes in a Hive/Hadoop environment, kept all metadata on a Db2 server, and had Tableau dashboards for operational support.
This framework was able to serve a team of up to ten developers and three support operators. We used it for ETL development for 17 retail and five insurance data warehouses. Later on, we migrated it to a GCP cloud.
The ETL framework was crucial for the company's growth, allowing it to expand development and support operations for at least five years.
Senior Data Architect
I designed a distributed data model for energy trading data. I then migrated data from the legacy system to Postgres and BigQuery. I also expanded the new architecture to new trading markets and designed ETL pipelines.
Senior Tableau Designer
I designed advanced visualizations for an innovative, cutting-edge vision technology that helps fruit growers produce more food on existing acreage. The visualizations presented ML results together with accurate data in a near real-time mode.
Education
1990 - 1996
Master's Degree in Mathematics and Computer Science
Dnipro National University - Dnipro, Ukraine
Certifications
JULY 2005 - PRESENT
Oracle Certified Professional
Oracle
Skills
Libraries/APIs
Sigma.js
Tools
Tableau, Erwin, Oracle Warehouse Builder (OWB), Sybase PowerDesigner, Informatica ETL, Microsoft Visio, Microsoft Power BI, GIS, Oracle Designer, Stitch Data, Spark SQL, Domo, Recurly, Terraform, Sigma Computing Data Visualization, Looker, BigQuery, Oracle Application Express (APEX)
Languages
SQL, Stored Procedure, Snowflake, Transact-SQL (T-SQL), Python, JavaScript
Frameworks
Hadoop, Scaled Agile Framework (SAFe), Data Lakehouse
Paradigms
ETL, Business Intelligence (BI), Kimball Methodology, Event-driven Architecture, Role-based Access Control (RBAC), Automation
Platforms
Oracle, Oracle Data Integrator (ODI), Google Cloud Platform (GCP), Amazon Web Services (AWS), Azure, Salesforce, Talend, Talend Stitch
Storage
PL/SQL, Apache Hive, IBM Db2, SQL Stored Procedures, Oracle 12c, Microsoft SQL Server, Oracle PL/SQL, PostgreSQL, Databases, Data Pipelines, Dynamic SQL, Database Administration (DBA), Database Backups, Teradata, Google Cloud, Google Cloud SQL, Amazon DynamoDB, Data Lakes, Azure SQL, SQL Performance, Master Data Management (MDM)
Other
Data Architecture, Big Data, Data Warehousing, erwin Data Modeler, Team Leadership, Business Analysis, Solution Design, Data Marts, ETL Specification, Data Warehouse Design, Google BigQuery, Data Engineering, Data Analytics, Data Visualization, Data Modeling, Data Analysis, Statistics, Data Migration, Performance Tuning, Data Governance, Query Optimization, Data Strategy, Backup & Recovery, Reporting, Solution Architecture, Data Governance, Business Intelligence (BI), Data Architecture, Data Reporting, Data Quality, Data Analysis, Mathematics, Computer Science, SAP BusinessObjects (BO), Data Vaults, Unix Shell Scripting, Enterprise Resource Planning (ERP), Oracle Forms & Reports, Machine Learning, Wearables, Fivetran, Data Product Management, MicroStrategy, APIs, Azure Data Factory (ADF), CI/CD Pipelines, Modeling, PostgreSQL 9, Search, Vector Search, Medallion Architecture, iPaaS, Data Build Tool (dbt), Inventory Management, Picas, Analytics, Board Reporting, Customer Data, ELT, Architecture
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