Archives

VertiPaq's xpress8 compression is raw MS-XCA LZ77 behind a two-field wrapper, and Windows has shipped a decoder for it all along. Enough to read the Power Pivot model inside an Excel workbook from a PowerShell script with no dependencies.

PBIXRay is a native macOS app for opening and inspecting Power BI PBIX files, including the model, DAX, Power Query, data and report structure.

A visual companion to the row-ordering article — step through the greedy bucket-splitting algorithm that VertiPaq uses to maximise RLE compression.

Excel workbooks with Power Pivot models contain the same Analysis Services and VertiPaq storage ideas as PBIX files. This article shows how PBIXRay reads them directly from Python.

PBIX.info: a browser-based PBIX inspector built on WebAssembly. Local-first parsing, interactive diagrams, and shareable collaboration links.

How VertiPaq appears to use a greedy row-reordering algorithm to maximise RLE compression across all columns in a segment.

How VertiPaq stores column segments in .idf and .idfmeta files, and how those files combine to reconstruct imported table data from a PBIX file.

How VertiPaq stores dictionaries and hash indexes inside a PBIX file, and how those structures help turn internal IDs back into readable values.

Extract tables, measures, M queries, and report metadata from any PBIX file using the open source Python library PBIXRay — no Power BI required.

How metadata.sqlitedb inside a PBIX file exposes the semantic model as an embedded SQLite database, mirroring the same objects as TMSCHEMA DMVs.

Power BI embeds a full Analysis Services Vertipaq engine inside every PBIX file. This article explains how the DataModel stream works and what it contains.

A PBIX file is a ZIP archive. Here's a map of every entry inside it — what each file does and how they relate to one another.

An introduction to the .pbix file format — what it contains, how Power BI uses it, and why its internals matter for developers and data engineers.