Avoiding truncation errors in Microsoft Fabric Data Warehouse: Understanding UTF‑8, collations, and column lengths
Loading data into a Microsoft Fabric Data Warehouse can feel effortless—until it suddenly isn’t. Being a total MS Fabric noob, the following error message caused some confusing and brough me on a learning journey I like to share: String or binary data would be truncated while reading column of type 'VARCHAR(255)'. Turns out that if you’re working with Parquet files, multilingual data, or Copy Into pipelines, this error can appear even when the source column seems to match the target column. In this post, I’ll walk through why this happens, why collation changes alone don’t fix it, and what you can do to avoid it. The scenario I was loading data from an on premise datasource through a data gateway into a Fabric Data Warehouse table. The target column is defined as: NAME_LB VARCHAR(255) To already give you a hint, the source column contains values like: RÖ The column lengths match. I even switched the collation to a UTF‑8 compatible one: COLLATE Latin1_General_...