Legacy Netezza to Snowflake migration

When a legacy platform is switched off, every report sitting on top of it has to be rebuilt somewhere else without the business noticing a gap. That was the job as Netezza was decommissioned: move the reporting and data workloads onto Snowflake and keep the outputs stable throughout.

The work was equal parts detective and builder. First, understand what the existing solutions actually did, including the undocumented parts. Then rebuild the transformation logic on Snowflake, validate that the new outputs matched the old ones, and support the users who relied on those reports through the change.

What it involved

• Analysing existing Netezza-sourced solutions to understand the real logic, not just the documented logic.
• Rebuilding transformation logic on Snowflake with dbt.
• Validating outputs against the legacy versions so numbers stayed trustworthy through the switch.
• Supporting business users through the transition.