How Carrefour is lowering its Oracle footprint

When Nicolas Forgues joined Carrefour as its CTO in early 2020, the French retailer was exploring how to accelerate cloud transformation and adopt new IT capabilities, such as DevOps.

Forgues spent almost a year and a half there, working on a plan involving the reduction of the company’s legacy Oracle footprint, before leaving in September 2021 to join the IT consultancy, Veltys as a partner. Speaking of the project, which began during his tenure at Carrefour, Forgues says it involved a migration to PostgreSQL and a strategy to switch to a software-as-a-service (SaaS)-based line of business systems.

He says the company was also looking to rejuvenate its open source software strategy. “Open source was previously a recommendation, not a big pillar of the company’s technology strategy,” he explains.

Carrefour’s main database management system is Oracle and the company runs a number of releases from version 8 to version 12c, which are used by business applications. For instance, Oracle is used in price optimisation and analytics. The company also operated an Exadata on-premise system. Forgues estimates that the annual maintenance fee the company paid to Oracle was in the order of €5m.

Like many organisations, Carrefour needed to work within the constraints of Oracle licensing, especially in terms of deploying software on virtual servers. “You have the challenge of bringing your own licences,” says Forgues. “With virtualisation, you cannot move licences as is. You are required to license the whole server cluster.”

The company’s digital transformation strategy in 2018 put pressure on IT to find cost savings. “To reduce cost, we looked at our main expenses, such as Oracle, and looked at the trajectory,” says Forgues, adding that commercial software providers do not readily rip out and replace the underlying database system on which their software is built. This limited the applications that Carrefour could migrate from Oracle to those that had been developed in-house.

With the company’s home-made applications and analytics, Forgues says Carrefour was able to reduce its Oracle footprint significantly by switching the underlying database it relied on to Postgres (PostgreSQL). “I knew from my time at Air France that Postgres has achieved a level of  maturity where you can run critical workloads,” he adds.

“But we needed to find ways to fund the migration,” says Forgues. Carrefour selected third-party support provider Rimini Street in a bid to reduce its Oracle support costs. The goal was to combine Rimini Street’s third-party support with a migration of in-house applications to Postgres and use Oracle Cloud when required.

Discussing the negotiations with Oracle, Forgues says: “It was very tense with Oracle. Our strategy was that we would  have no on-premise Oracle maintenance. Either we use Rimini Street or move to Oracle’s database-as-a-service. We did not want to be stuck on a three-year Oracle contract.”

Within a year, Carrefour was able to move all its on-premise Oracle support over to Rimini Street, he says.

Discussing the approach Carrefour took to rebuilding its in-house applications for Postgres, Forgues says: “We began moving all the easy applications, but Oracle applications that have been developed using stored procedures require more work. If it’s a heavy transformation, it may be too costly.”

For the commercial off-the-shelf applications, he says: “We started to look long-term at vendors that are not Oracle-based.” This requires change management, he adds. 

Carrefour’s IT function is divided into business-orientated teams, each of which is essential when discussing the migration to Postgres, says Forgues.

Just as when his team helped the business to identify potential in-house-developed code as candidates to migrate to Postgres, they also needed to help people in the IT team responsible for line-of-business software to decide on a strategy for keeping or moving off Oracle-based applications. 

Because the business aims to be cloud-first, Forgues says priority is given to SaaS over platform-as-a-service (PaaS) deployments, and this is ahead of infrastructure-as-a-service (IaaS)-based options, where the application is effectively hosted on a public cloud. Above all, he says, “we want to avoid on-premise systems”.

Many newer enterprise software packages are now SaaS-based, which helps to reduce costs. “That is how we engaged them,” says Forgues. “All costs are linked back to the business. It is in their interest to reduce cost.”

But when discussions began in 2021, Forgues says there was no budget on the business side to consider kicking off an application migration strategy that was not set to start until 2023. He explains: “When you start the discussion, it is difficult for people to see the urgency when the planning period is over a year.”

Forgues’ approach involved partnering with the team responsible for the platforms the business used. “We showed the benefits, anticipated choices, defined a roadmap and identified which application we could get rid of,” he says.

When looking for potential products, Forgues says: “We would prefer to find a non-Oracle-dependent vendor.” Carrefour is expected to start application migration from 2023.