Case Study
5 October, 2026
How TeraSky helped a global fintech company move 200+ critical reports to BigQuery while preserving business logic and data trust.
In financial analytics, a report is never just a report. It represents years of embedded business rules, calculations, and compliance standards. Moving these environments to the cloud is a high-wire act: the underlying technology changes completely, but the final numbers must remain exactly the same.
This was the challenge a global fintech company brought to TeraSky. The organization, which serves millions of businesses, relies on its analytics platform for day-to-day operations, regulatory reporting, and executive decisions.
Over time, this system had grown into a multi-terabyte data warehouse containing hundreds of connected processes. More than 200 of these reports were critical to the business, with some containing over 1,000 lines of complex SQL and PL/SQL logic. The company needed to modernize this massive footprint without disrupting its ongoing global operations.
The Hurdle: Translating Legacy Logic to the Cloud
The client’s target destination was Google Cloud, using BigQuery as the central data warehouse and Looker for reporting.
The main obstacle was architectural. The company’s legacy reports relied heavily on procedural SQL and PL/SQL logic. BigQuery, however, is built for large-scale, distributed analytics and handles data differently. Because the reports couldn’t be copied over, the team had to rewrite, validate, and optimize the logic from scratch to run efficiently in the cloud.
Balancing Preservation and Modernization
To manage this shift smoothly, TeraSky and the client mapped out exactly what needed to stay the same versus what needed to evolve:
| What Had to Stay | What Had to Change |
| Financial Accuracy: Exact business rules and calculations. | Code Architecture: Rewriting PL/SQL into optimized BigQuery logic. |
| Operational Continuity: Meeting strict regulatory deadlines during the move. | Processing Speed: Reducing long-running queries to fit tight reporting windows. |
| Data Trust: Maintaining absolute faith in the final numbers. | Data Cleanliness: Finding and fixing hidden inconsistencies in legacy reports. |
| Business Value: Ensuring uninterrupted access to financial insights. | User Experience: Shifting reporting and dashboards to Looker. |
How the Migration Was Delivered
The company had already worked with TeraSky across multiple cloud and data initiatives, which gave the teams a shared understanding of the environment, the standards, and the level of care required for business-critical systems. This time, TeraSky’s experts worked directly with the business, finance, and technology teams to rebuild the enterprise data warehouse on BigQuery.
The bulk of the effort went into translation and validation. TeraSky analyzed the legacy SQL and PL/SQL processes, preserved the underlying business rules, and redesigned the reporting logic for BigQuery’s analytical model.
Where standard migration patterns or built-in platform capabilities were not enough, TeraSky engineered custom extraction and integration mechanisms to close the gap. These tailored components addressed platform-specific challenges while keeping the modernization aligned with Google Cloud best practices.
Validation was built into every step. TeraSky worked side by side with the company’s data experts to compare outputs, reconcile discrepancies, and confirm that the new cloud reports preserved the intended financial meaning.
This careful checking also helped the team uncover and correct inaccuracies in some legacy reports, strengthening trust in the data the client’s teams rely on.
The Impact
By migrating, validating, and optimizing more than 200 financial reports, the project delivered immediate operational wins:
- Massive Performance Gains: Critical reports that previously took hours to compile now finish in under 10 minutes.
- Reliable Compliance: Faster processing ensures the finance team consistently hits operational and regulatory reporting deadlines.
- Improved data quality: The migration revealed inconsistencies in legacy reports that could be corrected during validation.
- Future Readiness: The clean BigQuery and Looker foundation makes the platform easier to maintain and prepares the company for future self-service data and AI initiatives.
The project also showed the value of TeraSky’s engineering approach. When requirements could not be met through built-in platform capabilities alone, TeraSky designed custom extraction and integration mechanisms that fit the customer’s needs while preserving the integrity, governance, and maintainability of the new Google Cloud environment.
By combining deep technical migration skills, tailored engineering, and a meticulous validation process, TeraSky successfully moved the organization to a faster, more scalable cloud platform. The company achieved total modernization without sacrificing the historical data integrity and business logic on which its global operations depend.
“This was a sensitive migration because the reports carried years of business logic. TeraSky helped us protect that logic, validate the results, and move to a faster, more scalable platform. The process also helped us identify and correct issues in some legacy reports, which strengthened trust in the data.” – Client VP of Data & Analytics
Technologies Used
Google BigQuery | Looker | Google Cloud Platform