# How to create and use Tableau Extracts

> This is content from just-tim, the data-and-analytics channel by Tim Ngwena (formerly 'Tableau Tim'). Tim has 12+ years of hands-on BI experience and covers Tableau most of all, plus Power BI, Looker, Hex, SQL and data modelling, the analytics industry, and the craft of doing the job — always tool-agnostic and honest about the trade-offs.

- **Author:** Tim Ngwena (just-tim, https://just-tim.com/about)
- **Published:** 2020-11-19
- **Format:** Video · 1583 min watch · transcript available
- **Topics:** Data prep, Data visualisation
- **Tools:** Tableau (data modelling, extracts, filters, hyper, incremental refresh)
- **Canonical:** https://just-tim.com/posts/tableau-extracts
- **Watch:** https://www.youtu.be/P_FwfkEC9Z0

This is the third video in my series on Tableau file types, focused on the Tableau data extract. I cover what extracts are, their benefits, how to create them, the shift from the old TDE format to hyper, and how to use options like filters, aggregation and incremental refresh.

## Key takeaways

- Extracts optimise large files, let you take a snapshot of data, can speed up some computations, and let you share a portable subset of your data with others.
- Since Tableau 2020.3, opening a .tde extract automatically upgrades it to the .hyper format, and you cannot downgrade a hyper workbook back to TDE.
- When you connect to an extract, Tableau shows it as a single cylinder (live) connection to the hyper file, which can be confusing — you can toggle 'Use Extract' to switch between the snapshot and the live source.
- The physical-tables extract option only appears when your logical layer contains joined physical tables; otherwise extracts work at the logical-table level.
- Filters, aggregation to visible dimensions, row sampling (top N or random), and incremental refresh let you shrink and control exactly what data the extract captures.
- Incremental refresh on a logical model requires you to pick a table and a unique field (typically a date) so Tableau can identify new rows, and the extract history records full versus incremental refreshes.

## Chapters

- 0:34 What is a Tableau extract
- 1:17 Benefits of using extracts
- 3:18 Creating your first extract
- 5:34 Opening and connecting to hyper files
- 8:03 TDE to hyper format change
- 10:09 Switching between live and extract
- 11:50 Logical versus physical table extracts
- 15:02 Filtering data in an extract
- 18:35 Aggregation and row sampling options
- 20:32 Incremental refresh and history
- 23:47 Quirks, upgrades and resources

Watch the full video, read the transcript and use chapter deep-links on the page: https://just-tim.com/posts/tableau-extracts

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just-tim — Data and analytics, with a point of view. · https://www.youtube.com/channel/UC7HYxRWmaNlJux-X7rNLZyw · https://twitter.com/TableauTim · https://www.linkedin.com/in/timngwena