Posts

All the articles I've posted.

• Windows Already Ships the Decompressor Power Pivot Needs

  12 Aug, 2026

  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 for macOS: Open and Inspect PBIX Files on a Mac

  23 Jul, 2026

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

• How VertiPaq Sorts a Table — A Visual Walkthrough

  16 May, 2026

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

• Parsing Power Pivot Data Models from Excel XLSX Files

  12 May, 2026

  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 Parsing in Your Browser: Introducing PBIX.info

  27 Apr, 2026

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

• How VertiPaq Sorts Rows to Maximize RLE Compression

  21 Apr, 2026

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

• Reconstructing Column Data from .idf and .idfmeta

  14 Apr, 2026

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

• VertiPaq Dictionaries and Hash Indexes

  7 Apr, 2026

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