Evgenii Timofeev, Developer in Petrovac, Budva Municipality, Montenegro
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Evgenii Timofeev

Verified Expert  in Engineering

Data Engineering Developer

Petrovac, Budva Municipality, Montenegro
Toptal Member Since
June 18, 2020

Evgenii has around nine years of database development experience, with a primary focus on building and optimizing data warehouses. He started his professional career as an SQL engineer-analyst in one of RosTeleCom Mobile holdings and was promoted to analytical reporting team manager in two years. During his career, Evgenii has participated in several telecom OSS and BSS migration and integration projects, including Tele2 Rus, Optus AU, and Telenet BE.


Samsung NEXT
Apache Airflow, Python 3, ClickHouse, PostgreSQL, MySQL, Data Pipelines...
Apache Ignite, Cassandra, Java, Shell, Oracle PL/SQL, Apache Airflow...
Java, Shell, Oracle PL/SQL, PL/SQL Developer, DBeaver, Oracle SQL, PL/SQL...




Preferred Environment

Git, IntelliJ IDEA, DBeaver, PL/SQL Developer, DataGrip, SQL, Oracle PL/SQL

The most amazing...

...thing I've coded and driven is the migration of the analytical DWH of RosTeleCom Mobile into Tele2 Rus systems.

Work Experience

Senior Data Engineer

2021 - PRESENT
Samsung NEXT
  • Implemented data pipelines based on Apache Airflow. These data pipelines collected information from different data sources like PostgreSQL, MySQL, Instagram API, Mixpanel, etc., into ClickHouse.
  • Administered machine learning features data collection into a separate database for recommendation system recalculation.
  • Created complex SQL queries on ClickHouse SQL to implement analytical dashboards. Tuned and improved existing analytical reports.
Technologies: Apache Airflow, Python 3, ClickHouse, PostgreSQL, MySQL, Data Pipelines, DataGrip

Lead Software Engineer

2019 - 2021
  • Tasked with internal code delivery drops on build and testing within my stream.
  • Managed a team of five developers. Decomposed, set, and controlled tasks.
  • Made the LOE, scope of work, and time frame estimations.
  • Communicated with the project team, conterminal streams, and customer representatives.
Technologies: Apache Ignite, Cassandra, Java, Shell, Oracle PL/SQL, Apache Airflow, Apache Hive, Python 3, PL/SQL Developer, DBeaver, Oracle SQL, PL/SQL, Data Engineering, PL/SQL Tuning, Data Migration, Migration, Python, Data Pipelines, Team Management, Software Development Management, Spark SQL, Spark, PySpark

Senior Software Engineer

2016 - 2019
  • Developed PL/SQL transformations into an entity–attribute–value database and validations according to migration documents.
  • Managed post-migration activities as a data migration lead with four subordinates. Analyzed customer requests, improved system function and speed, fixed bugs and design, and distributed and controlled tasks between subordinates.
  • Verified and modified migration rules during discussions with business analysts.
  • Looked for migration speed bottlenecks and tuned SQL transformations.
  • Participated in meetings with customer representatives and provided consultations to the onsite team regarding migration procedures.
Technologies: Java, Shell, Oracle PL/SQL, PL/SQL Developer, DBeaver, Oracle SQL, PL/SQL, Data Engineering, PL/SQL Tuning, Data Migration, Integration, Migration, Data Pipelines

Lead Database Programmer

2015 - 2016
  • Developed a database structure based on the entity–attribute–value model. Created Oracle PL/SQL procedures and packages.
  • Optimized database search time with Oracle Text index as part of my role.
  • Created a database back-end REST API using Oracle ORDS utility.
  • Developed a Pentaho Data Integration schema for database migration from Oracle to PostgreSQL.
  • Developed a PostgreSQL integration with MS SQL server for using data in MS SSAS, including ETL chains and subprograms on Janino.
Technologies: SSAS, Microsoft SQL Server, Pentaho, PostgreSQL, Janino, Java, Redgate, Oracle REST Data Services (ORDS), Index, Oracle, RMAN, PL/SQL Developer, Oracle SQL, PL/SQL, Data Engineering, PL/SQL Tuning, Migration

Analytical Report Team Manager

2014 - 2015
  • Executed and controlled monthly and yearly billing procedures.
  • Administrated and controlled Teradata Churn CRM integration procedures.
  • Developed the data warehouse structure and PL/SQL package for flexible schemes of dealers settlement and reward and a dealers fraud identifying reports system.
  • Set, split, and controlled tasks between three analytical reporting group developers, motivated subordinates, and coordinated vacation schedules.
  • Managed and orchestrated the CJSC NSS statistics system migration into the Tele2 Russia informational system.
Technologies: Java SE, Churn Analysis, Teradata, OLAP, BSS, SQL, Oracle PL/SQL, Oracle SQL, PL/SQL, Data Engineering, PL/SQL Tuning, Data Migration, Migration, Data Pipelines, Team Management, Software Development Management, Data Analysis, Data Analytics, Analytics Implementation

Analytical DB Engineer

2011 - 2014
CJSC "NSS" (RosTeleCom holding)
  • Developed and optimized SQL requests to the billing system.
  • Developed the load-base statistics maintaining system for telecom base stations.
  • Enlarged and improved the analytical data warehouse system, integrated with numerous data sources for report system optimization.
  • Analyzed and developed single and periodic analytic reports according to management expectations.
  • Developed a program pack for working with content providers using Java SE and Oracle 10g PL/SQL.
Technologies: Java SE, PL/SQL, Oracle SQL, SQL, Oracle PL/SQL, Data Engineering, Analytics Implementation, Data Analysis, Data Analytics

Base Operator Migration into NetCracker BSS & OCS Systems

The process for migrating Base Operator (a part of Telenet Belgium) customers from a legacy system to a NetCracker real-time billing and rating management system.

I was an OCS (online charging system) migration team lead, came into the project when the migration design was almost finished. However, due to numerous product code changes, the design had to be changed several times dramatically. Also, because of the absence of OCS migration business analysts, I had to proactively communicate with the product implementation team and the customer, performing analysis and design by myself to create and split implementation tasks between team members.
I was also responsible for executing SVT tests, analyze results, and find ways to improve performance in all parts of the OCS migration ETL—Oracle PL/SQL scripts for data extraction and preliminary transformation, Java/Kotlin application for data transfer, and Grafana logs for monitoring Apache Cassandra load.
From the people management perspective, I was doing all the regular team lead activities: tasks decomposition, distribution and control, delivery planning, new features assessment, and ETA calculation.

SingTel Optus Migration into NetCracker OSS System

Successful migration of Australian Optus operator's OSS systems to the NetCracker TOMS engine.

As a senior developer, I've created transformation, validation, and reconciliation scripts for millions of records to be processed and uploaded into the EAV data model during migration. A huge part of this work was Oracle SQL tuning and PL/SQL scripts development for matching customers' NFRs for migration timeframes.
After the migration, I continued to work on this project as a post-migration support team lead, distributing data fixes between team members and working with the customer's data extract team on new data integration CRs (customer requests).

Nizhny Novgorod Communications to Tele2 DWH Migration

This project focuses on the management and orchestration of CJSC "NSS" (Nizhny Novgorod Communications) statistics system migration into the "Tele2 Russia" informational system. This migration was necessary after the sale of RosTeleCom PJSC's mobile assets to Tele2 Russia LLC. Our primary objective was to align the analytical and reporting system of CJSC "NSS" with the standards set by Tele2.

I led a team of analytical reporting developers responsible for the migration process. We aligned the systems by conducting system comparisons, collaborating with Tele2 data development and marketing teams to ensure mapping and ETL design, determining hardware requirements, performing data validation and performance checks, coding and executing ETL processes, and providing post-migration support.
2008 - 2013

Specialist Degree (Master's Degree Equivalent) in Computer Science in Economics

Lobachevsky State University of Nizhnii Novgorod - Nizhnii Novgorod, Russia


Apache POI, Apache HttpClient, PySpark


IntelliJ IDEA, Git, RMAN, Redgate, SSAS, Shell, Apache Ignite, Apache Airflow, DataGrip, Jira, Postman, Pentaho Data Integration (Kettle), TortoiseSVN, Subversion (SVN), Spark SQL




PL/SQL Developer, Oracle SQL, PL/SQL, Data Pipelines, Oracle PL/SQL, Oracle 11g, Data Integration, Oracle RDBMS, Data Validation, DBeaver, Teradata, Microsoft SQL Server, Cassandra, Apache Hive, PostgreSQL, SQL Server 2012, ClickHouse, MySQL


SQL, SQL DDL, Java SE, Python 3, Kotlin, Python, Java 8, Java


Oracle, Pentaho

Industry Expertise



Hibernate, JUnit, Spark


PL/SQL Tuning, Data Migration, Migration, Integration, Data Engineering, Software Development Management, Remote Team Leadership, Telecom Business Support Systems (BSS), Data Warehouse Design, Team Management, BSS, Churn Analysis, Index, Oracle REST Data Services (ORDS), Janino, Apache Cassandra, Analytics Implementation, Data Analysis, Data Analytics

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