# Tableau 2020.2: Incremental refresh in Tableau Prep Builder

> 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:** 2020-05-06
- **Format:** Video · 9 min watch · transcript available
- **Topics:** Data prep
- **Tools:** Excel; Tableau (performance, prep)
- **Canonical:** https://just-tim.com/posts/tableau-2020-2-incremental-refresh-in-tableau-prep-builder
- **Watch:** https://www.youtu.be/PnmiKdXqG_0

I walk through the incremental refresh capability added to Tableau Prep Builder in Tableau 2020.2. Using the sample superstore data, I show how to set up incremental refreshes and append data so that only new rows are processed rather than re-running calculations across the entire data set.

## Key takeaways

- Incremental refresh in Tableau Prep is configured in the input settings, but you must first build out the full workflow and create an output before it can be enabled
- You identify new rows using a field that always updates with new records, such as order date, and Prep matches this against a corresponding date field in the output
- On the output step you can independently control what a full refresh versus an incremental refresh does, including setting a full refresh to only append data for growing historical data sets
- Incremental refresh only processes new rows, so calculations like date differences are not recomputed for data that has already passed through the flow, which is vital for very large data sets
- The feature is especially powerful when running Tableau Prep Conductor on Server or Online, letting you process only incremental additions rather than the entire history each run

## Chapters

- 0:14 Setting up the input and files
- 1:18 Enabling incremental refresh
- 2:00 Building the workflow and output
- 3:40 Configuring refresh options
- 4:40 Running the flow and fixing the write error
- 5:44 Appending new data and testing the refresh
- 6:54 Why incremental refresh matters

Watch the full video, read the transcript and use chapter deep-links on the page: https://just-tim.com/posts/tableau-2020-2-incremental-refresh-in-tableau-prep-builder

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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