8.2 — How Direct Lake Works

Direct Lake connects three layers seamlessly:

1. OneLake

Unified storage — one copy of data for the entire analytics estate.

2. Delta Lake

Open, ACID‑compliant tables stored as Parquet files with transaction logs.

3. Semantic Models

Power BI’s modeling layer reads directly from those Delta files — no engine in between, no copy, no cache refresh.

That’s why it’s fast. The data never moves. The model just reads it.

Direct Lake vs Import vs DirectQuery

Feature	Import	DirectQuery	Direct Lake
Refresh required	Yes	No	No
Real‑time	No	Yes	Yes
Performance	High	Low	High
Source load	None	High	None
Data duplication	Yes	No	No
Storage cost	High	Low	Low
DAX support	Full	Limited	Full
Best for	Small datasets	Operational dashboards	Enterprise BI

Direct Lake wins on every axis that matters for enterprise analytics. It’s not a compromise — it’s a genuine step forward.