.png)
Data Extraction
A data extract is a compressed, optimized snapshot of your data that Tableau stores in its own fast in-memory engine (Hyper), separate from the original data source.
Creating an Extract
Data menu -> select the data source -> Extract Data...
Choose filters and aggregation options -> SaveWhy Use an Extract?
- Much faster performance than querying large live databases repeatedly.
- Allows offline work when disconnected from the original data source.
- Can pre-aggregate or filter data to reduce file size.
Refreshing an Extract
Because an extract is a snapshot, it needs to be refreshed to reflect new data - this can be done manually in Desktop or scheduled automatically on Tableau Server/Cloud.
Data menu -> Extract -> RefreshExtract vs Live Connection
A live connection always reflects the current state of the source but can be slower on large datasets; an extract is faster but only as current as its last refresh.
For large, slow-changing datasets, extracts often give the best balance of speed and simplicity - but for real-time dashboards, a live connection is usually the better choice.