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Tableau Data Extracts are snapshots of data optimized for analysis and reporting. A short dive into the idea of data extracts – snapshots of data optimized for analysis and reporting. |
Tableau Data Extracts are snapshots of data optimized for aggregation and loaded into system memory to be quickly recalled for visualization. Extracts tend to be much faster than live connections, especially in more complex visualizations with large data sets, filters, calculations, etc.
… When you create an extract from a local file (such as a .csv or an Excel workbook) or an on-premise database, you’re speeding up the workbook through optimization.
– https://www.tableau.com/blog/tableau-cloud-tips-extracts-live-connections-cloud-data
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