The challenge
A tier-1 European bank was running its risk, finance and treasury analytics on a 12 PB Teradata estate that had grown unwieldy over 15 years. Cost was escalating, query concurrency was constrained, and the data science teams could not access Teradata-grade features (Snowpark, Iceberg, Cortex). The bank wanted to move to Snowflake without breaking the regulatory analytics the business depended on.
What we delivered
ByteWave led a 9-month, multi-wave migration: semantic-equivalence validation, Snowflake target architecture, data migration via Snowpipe Streaming & Snowpark, dbt transformations, Horizon Catalog governance, FinOps policy and a full parallel-run / cutover playbook signed off by internal audit, the regulator and the bank’s CRO.
Engagement highlights
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01
Semantic equivalence harness Automated comparison of 4,200 Teradata queries against Snowflake equivalents, with row-level diff, statistical tolerance and explainable failures.
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02
Wave-based cutover 6 waves over 9 months: Finance, Treasury, Risk, Customer, Compliance, AI workloads. Each wave: parallel-run, sign-off, cutover, decommission.
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03
Horizon Catalog governance Tag-based PII masking, row access policies, lineage, GDPR right-to-erasure, retention, BCBS 239 risk-data aggregation controls.
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04
Snowpark for risk models Python UDFs ported from SAS, ML scoring for credit risk, IFRS 9 staging tables, IFRS 17 reserving models, Snowpark-optimized warehouses.
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05
FinOps from day one Resource monitors, query acceleration, dynamic tables, materialized views, capacity commitments; 41% reduction in annual warehouse spend.
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06
Regulator-ready evidence Audit pack with lineage, access policies, query history, BCBS 239 control mapping, signed by internal audit and the regulator’s data team.
Outcomes
- 41% lower annual warehouse spend vs Teradata run-rate.
- 6× faster p95 query latency on risk dashboards.
- Zero critical defects at cutover.
- 100% PII tagging coverage across catalog.
- BCBS 239 risk-data aggregation controls met.
- Snowpark ML scoring <2s per credit decision.
“ByteWave delivered the migration without a single regulator finding. The FinOps outcome alone paid for the engagement twice over.”
— Group CDO, Tier-1 European Bank