Yongsheng M

PostgreSQL Consultant

Fiverr • Freiberufler

Dec 2023 - Present • 2 yrs 5 mos

Supported client to do Oracle to PostgreSQL migration. Offered technical services on PostgreSQL database performance optimization.

SQL expert & performance DBA

Home Credit China • Vollzeit

Dec 2017 - Oct 2025 • 7 yrs 10 mos

SQL Expert for SQL/Database Optimization in production OLAP(data warehouse) and OLTP (transactional) systems. Duties and Responsibilities: • Performance tuning and optimization for Oracle database and PostgreSQL database - SQL and Database performance optimization. - Database performance monitor and analysis. • Production Support for Oracle databases and PostgreSQL databases - Service Requests/Incident tickets for SQL optimization and other performance related issues. - Troubleshooting real-time database level performance hit. - Real-time SQL queries audit by identifying high cost SQLs through auto-monitor tool and manual check, provide recommendation to optimize inefficient queries. • Projects - Database Platform migration from Oracle database to PostgreSQL database - Setup HA solution (replication, auto-failover, scheduled backup，etc) for PostgreSQL database clusters.

Senior Oracle DBA

Xerox • Vollzeit

Dec 2007 - Dec 2017 • 10 yrs

• As the SQL Performance Expert takes full responsibility on SQL performance review and optimization for production online transactions queries, online ad-hoc queries and various customer reports. • As the Database Operation Expert in charge of database architecture, design, implementation, security compliance, troubleshooting, performance tuning for mission-critical 24*7 production databases. • As the Data Architect focus on high performance-sensitive data extraction, transform, loading, archiving and purging projects; works with developers on data analysis and modeling (reverse engineering) based on business process requirements.