Case Study

Teradata to Snowflake Migration Case Study


Customer's Challenge

A Pharmacy Benefits Manager serving 27+ million members was having major performance and reliability issues with their mission-critical Teradata data warehouse. As their contract came up for renewal, they wanted to move to Snowflake; but to undertake such a complex, high-stakes undertaking, they first had to find the right skills.

phData's Solution

phData not only achieved a successful data warehouse migration, but also implemented automation and design best practices to maximize the benefits. The result? Massive improvements in performance, scalability and efficiency — querying data across tables with 1.7 billion detailed rows, with zero failures and 90–97% faster completion.


Ultimately, the PBM is now positioned not only to scale their data warehouse with far better performance, but to support innovative new ways of monetizing the value of their data.

As one of our solutions architects put it: anyone migrating to Snowflake from an on-prem data warehouse knows there is “no easy button” to make it happen. But when you make the jump — and you do it with Snowflake-specific data ingestion, architecture, and operational best practices in mind — the results will speak for themselves.

The Full Story

Providing access to centralized pharmacy claims information is what Pharmacy Benefits Managers (PBMs) do; it’s what empowers them to help both pharmacies and insurers identify fraud, waste, and other potential savings.

In other words, their data is their value. So, when a certain PBM (serving 27+ million members throughout the U.S.) found themselves facing increasingly destabilizing performance issues with their on-prem Teradata data warehouse, finding a solution was a top priority.

The pain of poor data warehouse performance

It was clear to the PBM that performance and reliability issues with their data warehouse were hurting their bottom line. As they ramped up more concurrent users on the system to support the growth of their business, the issues only got worse:

One of the company’s most important business-critical applications was especially responsible for hampering the performance of other systems, but there were few options to remediate the problem without limiting access.

Ultimately, it was clear that the PBM’s existing systems couldn’t scale to meet their needs. With their Teradata contract coming up for renewal, they were eager to invest in a next-generation data warehouse platform, with a modern, cloud-based architecture. They became especially interested in Snowflake — not only because it could resolve their multi-tenancy issues and do what their existing system did more efficiently, but also because it provided the best support for new use cases, such as Data Sharing, that could potentially unlock new revenue streams.

However, they also understood that enterprise-scale data warehouse migrations bring complexity and risk. Knowing they needed deep expertise around Snowflake, they turned to phData’s team of specialists to map a path to a modern cloud-based platform with the ability to support both current and future needs.

A cloud-based treatment​​

phData provided a complete framework for the PBM to migrate Teradata workloads to Snowflake, complete with best practices, runbooks, and automation. To validate performance in Snowflake — querying across tables with 1.7 billion detailed rows — here’s what we did:

Proving the value of data warehouse modernization

The results after moving from Teradata to Snowflake were night and day. The PBM realized massive improvements in performance, scalability and
efficiency. Queries joining data across eight tables — three of which had 1.7 billion detailed rows — saw the following results:

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