Leo is available for hire
Hire LeoLeo Mepham
Verified Expert in Engineering
Software Developer
Norwich, United Kingdom
Toptal member since February 20, 2019
Bio
Leo has 15+ years of experience in database design, administration, data warehousing, ETL, capacity, and scale planning. He's familiar with multiple RDBMS and enjoys utilizing his skills in DevOps with infrastructure as code in both Azure and AWS as a server-side programmer in C#.
Portfolio
Thyngs
Amazon Web Services (AWS), SQL Server DBA, PostgreSQL, Database Performance...
CashChat
.NET, Amazon Web Services (AWS), PostgreSQL, .NET Core, C#, Entity Framework...
PrettyLittleThing (via Toptal)
SQL Server DBA, SQL, Microsoft SQL Server, Database Performance
Experience
- SQL - 15 years
- Database Performance - 15 years
- C# - 10 years
- Entity Framework - 10 years
- .NET - 10 years
- Amazon Web Services (AWS) - 6 years
- .NET Core - 2 years
- Azure Cosmos DB - 1 year
Availability
Part-time
Preferred Environment
Amazon Web Services (AWS), Azure, Core, C#, Git, Windows
The most amazing...
...database system I built used multiple front end fail-over groups that allowed tens of thousands of transactions per second with high availability and security.
Work Experience
Infrastructure and Software Engineer
2020 - PRESENT
Thyngs
- Migrated the platform from SQL Server to PostgreSQL by replacing the .NET Framework data access layer with a .NET Standard layer using .NET Core libraries for compatibility with other projects.
- Used AWS Schema Conversion Tool and AWS Database Migration Service for quick and safe migration of data. Achieved a significant saving on monthly database costs.
- Load tested with Artillery to discover maximum throughput at different virtual machine sizes. Used Visual Studio CPU profiling and AWS RDS Performance Insights to improve processing and throughput by a factor of ten.
Technologies: Amazon Web Services (AWS), SQL Server DBA, PostgreSQL, Database Performance, Entity Framework, ASP.NET, C#, .NET, SQL
Software Engineer
2020 - 2020
CashChat
- Built out an API in C# (.NET Core) for administering a mobile chat application with OpenIddict for authentication.
- Used a mixture of Entity Framework LINQ for tasks like user administration and raw SQL against a PostgreSQL DB for reporting queries.
- Dealt with stakeholders and front-end developers to get required dashboards and admin functions built and deployed.
Technologies: .NET, Amazon Web Services (AWS), PostgreSQL, .NET Core, C#, Entity Framework, ASP.NET, SQL
Top SQL Developer
2019 - 2020
PrettyLittleThing (via Toptal)
- Assessed the current setup of SQL Server instances and corrected setup and configuration issues.
- Examined indexing configuration, adding missing and removing unused indexes, and combining indexes to reduce IO and storage while still servicing queries.
- Set up log shipping and warm standby for minimal downtime during a major system and application upgrade.
- Advised on the modernization of SQL Server structures and usage of recent additions to the SQL Server engine to improve performance and stability.
- Proposed solutions for performance capacity increases and provided instruction and guidance on implementation.
Technologies: SQL Server DBA, SQL, Microsoft SQL Server, Database Performance
Contract Systems Analyst
2019 - 2019
Certas Energy
- Sent into a recently acquired software development company to assess their codebase. Produced written and graphical documentation from a board-level overview down to software module detail.
- Examined and detailed multiple software projects. Created data flow diagrams at a high level for PowerPoint board briefings, drilling down into low-level data flow diagrams of individual components useful for onboarding new development staff.
- Provided an overview of business and software functions to allow business streamlining and optimization.
Technologies: ASP.NET, C#, Delphi
Head of Engineering
2017 - 2018
Kodeshio
- Led the infrastructure, budgeting, load testing, and planning future areas for investigation and consideration.
- Designed and built a message bus to data lake to data warehouse systems and a B2B "Tenancy" application to create multiple private microservice ecosystems on a single-service fabric cluster.
- Implemented our CI/CD pipeline on VSTS, created custom tasks as required, and used ARM templates to give consistent IaC rollouts to the Azure platform.
- Assisted with Angular changes and additions where required.
- Built C# APIs for most microservices, keeping things simple, with versioning for older clients or native applications that will not update.
Technologies: ETL, .NET, Azure Cosmos DB, Angular, NServiceBus, Azure Service Fabric, Azure, C#, Database Performance, Entity Framework, SQL
Data Architect
2017 - 2017
Lightful
- Oversaw the data warehousing and ETL from primary data stores, later expanding my role to include designing and building the infrastructure in AWS.
- Created the whole platform in a single stack with extensive use of CloudFormation with Serverless for infrastructure deployments.
- Used Dynamo, Postgres, and Data Pipeline for data warehousing and ETL, AWS networking, and IAM for access control and security.
Technologies: ETL, Data Pipelines, DYNAMO, PostgreSQL, Redshift, Amazon Web Services (AWS), Serverless, Database Performance, SQL
Lead DBA
2010 - 2016
BGO
- Planned, designed, and built databases, data warehousing, and reporting systems.
- Ensured system performance and stability on a terabyte-scale system with thousands of requests per second via hundreds of concurrent connections.
- Oversaw the data migration from our own back end to a global leading back end and rewrote ETL systems to take from their source and schema to provide BI and executive-level overviews continuity.
Technologies: ETL, .NET, SQL Server DBA, SQL, Entity Framework, SQL Server Integration Services (SSIS), C#, Microsoft SQL Server, Database Performance, ASP.NET
Experience
Tournament.gg
http://tournament.ggUsing .NET Core, Entity Framework, C#, MySQL, AWS, and VSTS, we built the following aimed as a B2B quick-roll-out platform:
The tournament platform lets you create free-to-play competitions quickly and easily on both the web and our mobile apps. Available in both Play and App stores, you can reach a whole new audience where gambling businesses were previously not allowed.
The tournament platform lets you create free-to-play competitions quickly and easily on both the web and our mobile apps. Available in both Play and App stores, you can reach a whole new audience where gambling businesses were previously not allowed.
BGO Group
SQL Server, Availability Groups, Replication, Data Warehousing, Reporting, SSIS, ETL
Education
2002 - 2003
Higher National Degree in Software Engineering
Norwich City College - Norwich, England
2000 - 2002
Higher National Certificate in Software Engineering
Norwich City College - Norwich, England
Certifications
AUGUST 2013 - PRESENT
MCSE: SQL Server 2012
Microsoft Corporation
APRIL 2013 - PRESENT
MCSA: SQL Server 2012
Microsoft Corporation
Skills
Libraries/APIs
Entity Framework, NServiceBus
Tools
Git, Terraform
Languages
SQL, C#, DYNAMO, Delphi
Storage
SQL Server DBA, SQL Server Integration Services (SSIS), Database Performance, MySQL, PostgreSQL, Azure Cosmos DB, Data Pipelines, Microsoft SQL Server, Redshift
Frameworks
.NET, .NET Core, ASP.NET, Angular, .NET 5
Paradigms
ETL
Platforms
Amazon Web Services (AWS), Windows, Azure, Azure Functions, Azure Service Fabric
Other
Serverless
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