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With multiple table storage, however, Tableau Desktop will perform the join inside Tableau’s data engine during visualization query time. For single table storage, your source database will perform the join during extract creation.
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How to choose between Single table and Multiple table extract In certain cases, this will result in smaller extract file sizes, faster extract creation and potentially faster queries. Multiple table extracts: All the tables being used in the data source are stored separately in the extract file, mirroring the database structure.
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Single table extracts: The data is stored in file as a single table structure.
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Why use Tableau Data Extractsġ. Performance: Data extracts in general provide increased performance.Ģ. Reduce load on back-end systems: Replacing live connection to OLTP database or any other database reduces the load on the database.ģ. Pre-aggregations: An aggregated dataset is much smaller than the transaction level data extract which improves query performance.Ĥ. Materialization of calculated fields: When you optimize a Tableau extract, all of the calculated fields are pre computed and stored as static values in extract. The data extracts can be scheduled on the Tableau Server to refresh automatically. A Tableau data extract is a compressed snapshot of data stored on disk and loaded into memory as required to render a Tableau viz.