Position: Database/DWH Developer/Architect, SQL Developer
Category: SQL
Experience: 11 years | English: upper

Ph.D., technical sciences, the topic of the thesis was pattern recognition and  multi-class classification – classic machine learning challenges.

For the Behave project, data processing with recursive call of three levels of nesting stored procedures were developed. Recursion is a common practice for tables (CTE). But for stored procedures, I did not find anything similar on the internet forums.
Machine Learning were used to build models for results forecasting. Accuracy = 0.865 was achieved.
Approaches how to reduce the cost of using Azure Machine Learning Studio were found. 
Easy-to-use structured and well formatted analytical reports for clients directly in Excel format by means of MS SQL Server were created.

For the supply chain management project, I identified issues with the Snowflake Query Optimizer and proposed a solution for this problem. A typical query to update 10 rows in a one terabyte size table took 6 minutes, my approach did it in 5 seconds.
Another problem was a few seconds delay when fetching even small amounts of data. This was not acceptable for the user interface. A solution has been proposed for caching critical amounts of data. The solution was based on the MySQL database with MEMORY storage engine. The solution allowed to retrieve data from a table of one million rows in 0.0026-0.0053 seconds, which is close in productivity to what Redis can provide, but with SQL interface.

At Treasure Data’s Enterprise Customer Data Platform workflows that were implemented using Python have been rewritten using Trino (formerly Presto, SQL Engine for Big Data). Performance has been improved 10 to 40 times. For example, a task that ran for 13-15 minutes began to complete in 18-20 seconds. The workflow that took 2 hours and 20-40 minutes was completed in 4-6 minutes.

During Project 4 SQL scripts for Snowflake monitoring were developed and implemented, as well as logging approaches from Snowflake to Rapid7. Also, proposals for modifying the configuration of the MS SQL Server and Confluent to reduce the Recovery Time Objective (RTO) as well as Recovery Point Objective (RPO) in case of a disaster recovery (DR) were developed.
Skilled database/DWH developer with 20+ years of experience, specializing in Rest APIs, Microsoft Azure, MS SQL Server, Snowflake, Trino (ex. Presto), AWS, Redshift and database administration. Adept at architecting scalable database solutions for enterprise-level organizations. Have a proven track record of high client satisfaction. Dedicated to producing only the best work in the creation of effective and reliable databases/DWHs. Extensive experience with modifying databases, solving issues, and ensuring standards are properly met. Mentored other developers and oversaw the improvement of several applications. Devoted individual with the ability to successfully collaborate with coworkers to produce functional databases and smart solutions. 

Project 1: MS SQL developer at Behave, Luxembourg.
I was responsible for developing of a sophisticated analytical system: Refinitiv’s financial information analysis for investment professionals.
A database was created from the scratch. Extremely efficient stored procedures for statistical and analytical processing of huge amounts of financial information in the context of each day for decades were developed (hundreds of millions and billions of records in tables to proceed). 
Machine Learning were used for results forecasting (MS SQL R Services and Azure Machine Learning Studio).
The active development stage of the system was successfully completed. Used MS SQL, MS SQL R Services, Azure Machine Learning Studio, Azure Data Factory, R.
    Project 2: Database consultant at large German company, one of the activities - providing supply chain management. Very large amounts of data - 30 million new records per day. They planned to switch from Exasol to another, cheaper database. I helped evaluate the Snowflake database. Testing identified issues with the Query Optimizer for queries longer than one minute. A solution has been proposed for this problem. Used Exasol, Snowflake, MySQL, PostgreSQL, Python.
    Project 3: Senior Data Engineer at one of the largest tobacco corporations. One of the tasks: optimize the workflows at Treasure Data’s Enterprise Customer Data Platform. Used Presto, Hive, embulk, DigDag, Python.
    Project 4: Senior Data Engineer at one of the largest fintech (investment management solution) company. I was responsible for developing Snowflake monitoring/logging and disaster recovery approaches for MS SQL Server, Confluent (cloud Kafka), Atlas MongoDB and Snowflake.
For The Brave Knight There Would Be Always A Kingdom To Serve ;)
Interested in working with big data. I love to learn new tools and apply them in work.
I am looking for a long-term, stable and reliable relationship.
I like to work with data, analyze it, look for patterns and relationships.
At the moment I can perform tasks at the junction of Database Developer, Machine Learning, Data Engineer and Data Analyst.
I am currently learning BigQuery, Redshift and I am sure that I can be useful for your company if you are going to or already using this databases.
Architecture, storage and data processing in BigQuery and Redshift are very familiar to me after working with Snowflake, Hadoop and Presto.