What do you do when the implementation you paid for doesn't work?
After more than a year and more than $1 million, a previous vendor’s data warehouse implementation was unusable. We recommended starting over, rebuilt the integration in about three months, and it is still in use.
Rebuilding a failed data warehouse integration
The situation
The client had hired a contractor to implement a data warehouse. More than a year and more than $1 million later, the implementation did not work.
Meanwhile, the business was reporting the old way. Data from many systems was copied and pasted between spreadsheets, run through custom summary formulas, and emailed. By the time it reached the executive team, it was hard to know what the numbers meant or whether to trust them.
What was wrong
The queries that loaded the warehouse were enormous, and they still did not return correct results. They reloaded the entire database for every cell of data they retrieved.
The load was heavy enough that the cloud provider asked the client to stop running it, because it was affecting the provider’s own infrastructure. There was nothing in the implementation worth keeping.
What we did
We recommended scrapping the existing implementation and starting over. Making that case was the hardest part of the engagement, because the client had already invested so much in it.
We then rebuilt the integration and tested it. It was working in about three months.
What changed
The system is still in use. The client can now report on combined accounting, operations, and HR data in one place. Executives make decisions on data whose source they know.
