Developed various freelance projects using Java and open-source databases: PostgeSQL, MySQL, MongoDB and Apache Cassandra on Linux.

Participated in developing data processing pipeline. This ETL pipeline is based on Hadoop and Apache Hive; it’s preparing fraud data to be used by Data Scientists.Developed in-house Data Quality Framework using Java. This framework allows creating and executing data quality tests against any database via JDBC. Only knowledge of SQL is required to create such test in this framework.

Developed data migration procedure for CARS database.Participated in "Staff Auction" project. Responsibilities include data modeling, database performance analysis and tuning, development of PL/SQL packages.Tuned existing PL/SQL ETL processes including data feeds and data publishing procedures.Developed new data feeds as requested.Redeveloped existing data feeds to conform to new feed architecture.Developed infrastructure project for Consumer Report's databases. This project was about consolidation of all sachems of same environment into single database to eliminate unnecessary database links and synonyms. New database infrastructure allows streamline deployment to any environment.

Found worst performing queries using AWR reports.Tuned heavy queries provided by developers and ones found at AWR.Analyzed existing indexes and recommended changes when necessary.Compared production and test environments to find reason of performance variances.Made tests to check applicability of star transformation technique.Analyzed fragmentation of tables using segment advisor.

As part of iUFR project team worked full-time onsite customer location. Major responsibilities were data analysis and data validation.Provided support for ETL system (Oracle data warehouse builder).Provided support to database developers regarding writing optimal database queries.Revealed performance issues at Oracle database by analyzing data access path for most frequent queries. Suggested solution by adding necessary indexes and dropping inefficient ones.Optimized deployment procedure to shorten deployment process.

Worked full-time onsite customer location (UBS) as Oracle performance tuning expert. Communicate closely with developers and project manager of Martini project, product of SunGuard, regarding database design, stored procedures and query performance.Provide support to database developers regarding writing efficient database queries.Developed stored procedure to clean up outdated trades and related data. Data eligible for cleanup is backed up to external files first.Tuned several long running housekeeping jobs which led to dramatically reduced execution time.Analyzed data access path with help of Oracle Access Advisor using typical daily workload of system in order to achieve best possible performance gain.

Participated at development of Data Lifecycle Management project (part of eSpear infrastructure program of Deutsche Bank); production footprint of eSpear databases is approximately 50 terabytes and growing. Biggest tables were reorganized from non-partitioned to partitioned, data footprint reduced by deleting/archiving partitions with old data, which helped lower operational costs, increase DB efficiencies, and improve business processes.Participated at migration of eSpear system to Oracle Exadata platform. Non-current data compressed using Exadata Hybrid Columnar Compression (HCC). Optimized data access path by adding necessary indexes, eliminating inefficient indexes and providing required conditions for Oracle Exadata smart scan.Provided technical support for eSpear developers regarding efficient query writing, code review, troubleshooting, and performance tuning.

Managed incident reporting and resolved customer issues; facilitated the resolution of issues related to Oracle clusters (both RAC and HA); served as technical liaison with customer technical support.Provided Oracle support, opened and tracked service requests; installed and configured “hobbit” monitoring system for key customer; tuned databases to optimum levels of performance using Oracle statspack and AWR.

UkrTrade Ltd. is a retail company that runs network of twenty-four-hour supermarkets in Kharkiv; all sites are interconnected and required data replicated; several sites are already migrated to Oracle Real Application Clusters version 10g release 2 (others are in progress of such migration) to provide high availability and better performance.Managed installation, maintenance, tuning, troubleshooting, backup and recovery of Oracle databases; assisted Linux systems administrator with aspects related to database hosting; contacted vendors and recommended equipment purchases.Deployed Real Application Clusters configuration to several production sites to achieve 24/7 availability.Monitored and tuned systems and databases to optimum levels of performance; performed system upgrades in support of business processing requirements.Installed and configured “Big Brother” monitoring system on all production systems, which notified administrators of any issues with email and SMS protocols.Assisted developers with writing and tuning SQL queries; performed on-call support and problem resolution 24/7.

Provided consultancy service to clients regarding Oracle DB administration; migrated database of client’s system from MSSQL 2000 to Oracle 10g standard edition one; designed and deployed two-node database cluster on Oracle RAC technology.Automated backup of Oracle database using Oracle Recovery Manager; installed and configured Big Brother monitoring system; monitored and tuned systems and databases to optimum levels of performance.

Provided support for all environments - production, user acceptance test, quality assurance and development; being on-site operated closely with customer's managers as well as with developers, administrators and quality assurance engineers from Luxoft team; performed regular and ad-hoc reporting; assisted developers with writing efficient queries to database and tuning existing ones; setup new releases on UAT and production, provided troubleshooting support for customer's technical team.Made analysis of production database performance bottlenecks using STATSPACK utility; created reporting database using snapshot replication to offload production database; designed and developed database part of performance monitoring system.

Managed maintenance, tuning, troubleshooting, backup and recovery of production database; designed and deployed Oracle Data Guard configuration in production using maximum availability mode that provides best possible availability as well as no data loss. As Unix systems administrator, managed Linux and OpenBSD systems installation, maintenance, backup and troubleshooting.Migrated production environment from Oracle 7.3.4 database on SCO OpenServer 5 operating system to Oracle 9.2 database on RedHat Advanced Server 2.1 operating system on Intel Xeon-based servers; this provides developers with all features of modern Oracle database including performance improvements, administrators with new scalability, availability, manageability and security features. Installed and configured Intel Server Management and Big Brother monitoring system on all production systems; managed installation, configuration, and maintenance of servers for existing and new branches of bank. Assisted developers with writing and tuning SQL queries. Contacted vendors and recommended on equipment purchases.

Installed, upgraded, maintained, tuned, monitored and troubleshot Oracle databases; performed UNIX systems administration in-house, remotely in all branches and on customer sites. Involved in server-side development.Improved speed of acquisition phase of bill run process on 10 times by optimizing usage of Oracle SQL*Loader; migrated many stored procedures from MS SQL to Oracle; assisted developers with writing and tuning SQL queries.Adjusted database architecture to avoid predictable bottlenecks while adapting billing system for customers with big amount of data; designed and implemented backup strategy of half terabyte Oracle database; maintained cluster of two IBM p660 servers with IBM HACMP high-availability software; maintained several Sun servers.

Installed, upgraded, maintained, tuned, backed up, monitored and troubleshot Oracle databases. Designed data models, participated in development of database part of various projects.Redesigned part of data model, rewrote corresponding PL/SQL procedures and tuned Oracle database I/O to achieve required throughput for banner exchange system.Assisted developers with writing and tuning SQL queries.Setup product demos remotely on customer sites.