4 posts tagged with "Lakehouse"

Copying tables into a lakehouse is the easy part. The hard part is whether 0 means zero or was null in the legacy system, and whether a 0.01 drift is rounding or a bug.

I treat migration as a semantic contract, not a file move. Stakeholders do not celebrate that Delta exists. They celebrate that last month's margin still matches within agreed rules.

Figure 1. Shortcuts and schemas change where data appears, not what it means. Source: Microsoft Learn: lakehouse schemas.

Medallion architecture asks where bronze, silver, and gold live. In Fabric you can answer with many lakehouses or with schemas inside one lakehouse.

That choice leaks into shortcuts, SQL endpoints, notebooks, CI/CD, and how painful renames become later. It is not a folder preference. It is a topology decision.

Figure 1. Lakehouse creation in Microsoft Fabric. Source: Microsoft Learn: lakehouse schemas.

Moving a handful of warehouse views to Materialized Lake Views is a rewrite. Moving hundreds is a program. Teams that treat the long tail like a weekend notebook usually discover dependency order the hard way: gold breaks, silver thrashes, and bronze shortcuts were never registered as the real contract.

Frame the work as bronze to silver to gold with gates. Count the estate. Order by dependency. Prove a representative POC. Then convert with per-view notebooks so blast radius stays local. Success is parity plus runtime, not "the portal shows an MLV."

Figure 1. MLV migration is a program across bronze, silver, and gold. Gates belong between layers, not as a weekend cutover wish. Source: Microsoft Learn: medallion lakehouse architecture.

Medallion diagrams still tempt teams to land a physical bronze copy of everything upstream. When the upstream domain already publishes curated Delta in OneLake, that copy is not prudence. It is a second warehouse with a friendlier name.

Bronze can be a contract of shortcuts and thin clean views. Ownership stays with the publisher. Freshness follows the source. Your CI/CD list becomes the shortcut set, not a shadow catalog of cloned tables.

Figure 1. Bronze can be a pointer surface. Prefer OneLake shortcuts over copying bytes the platform already holds. Source: Microsoft Learn: OneLake shortcuts.