Newly created Fabric workspaces default to this Spark resource profile, controlled by spark.fabric.resourceProfile. Built for ETL and ingestion, it leaves V-Order switched off; reading suits readHeavyForSpark or readHeavyForPBI better.
Read more: Microsoft Learn
In the Ultra Transcenders books
Each book explains writeHeavy in context, with comparison tables and the common traps.
Terms in this definition
- Resource profile
A ready-made bundle of Delta Lake and Spark settings tuned to a kind of workload, chosen through spark.fabric.resourceProfile. The options are writeHeavy (V-Order off, and what new workspaces get by default), readHeavyForSpark, readHeavyForPBI (V-Order on) and custom.
- ETL
Extract, transform, load: data is reshaped before it reaches the target. Data Factory offers ETL and ELT as a managed service.
- V-Order
An optimisation Fabric applies to Parquet files as they are written, covering sorting, row-group layout, encoding and compression, so reads (above all Direct Lake) are quicker at some cost to writes. New workspaces have it switched off, and
OPTIMIZE ... VORDERapplies it to files already written. - readHeavyForPBI
A Spark resource profile in Fabric meant for tables that Direct Lake reports will read heavily; it enables V-Order and 1 GB optimize write bins. Workspaces created today use writeHeavy until changed.