Configure data loading (Beta)

Sigma uses queries to retrieve data from your connected data platform. To optimize performance and reduce the number of queries sent to your data platform, the browser cache is used. You can configure when an element uses the browser cache with Alpha Query to help accelerate the performance of some workbook elements.

To determine the best way to optimize performance for your workbook, see Best practices for improved document performance.

User requirements

You must have the Create, edit, and publish workbooks permission enabled on your account type and Can edit access to the workbook.

Configure data loading

To accelerate performance of your workbook, configure data loading for one or more elements in a workbook. Elements that benefit from configuring data loading are parent elements with multiple child elements and elements referenced by other elements, such as with a lookup.

To configure data loading:

1. Open a workbook for editing.

2. Open the workbook lineage to identify the optimal parent elements on which to configure this setting. Elements with multiple child elements are good candidates to configure data loading.

   

3. For each relevant parent element, click View element to open the workbook canvas with the element selected.

   

4. On the element toolbar, select More, then select Advanced options > Configure data loading....

   The Configure data loading popover appears.

   

5. Review the Diagnostics section to validate that the query results for the element can always be prefetched:

   • The Source row count is at least 1, and less than 10,000. If your data contains JSON columns, the row count must be less than 1,000.
   • The Source row count and the Output row count match.

6. For Alpha Query prefetch mode, select Always.

   Your changes are automatically applied to the workbook.

   Data loading for an element has 3 possible modes:

   Alpha Query prefetch mode	Effect
   Default	Sigma uses statistics and history to automatically decide when to prefetch data.
   Always	Sigma always prefetches data for this element to be used by other data elements in the document. If data in the browser cache can be used, use that data. If data is not in the browser cache, run a query against the connected data platform to retrieve the data.
   Never	Sigma never prefetches data for this element. Run a query against the connected data platform every time.

7. Publish the workbook for your changes to take effect on the published version.

8. (Optional) Review the query history for the workbook to confirm that the selected element is the only element that is retrieving data from the warehouse when the workbook is first loaded, and subsequent actions rely on browser calculations.

   

What happens when data loading is set to Always

When you have multiple elements in your document that use or reference the same data element, like as a data source or for a lookup, Sigma performs a "prefetch query" to retrieve the data for the referenced data element and store it in the web browser cache. Normally, the element must load before the connection timeout is reached (4 seconds by default). If the element takes longer to load, the prefetch query is cancelled.

For example, if you have 10 charts that use a table in your document as a data source, Sigma runs one prefetch query to retrieve the data for the parent table, rather than running 11 individual queries to retrieve the data for each of the data elements.

After that prefetch query is performed, Alpha Query can process the data, performing calculations with the cached data instead of querying the data warehouse for every element.

If you configure data loading to Always on a parent element, the element can take longer to load (more than the connection timeout, or 4 seconds by default) and the prefetch query still runs. After the prefetch query completes, the child elements use the cached data:

flowchart TD
    A[Parent element with Alpha Query set to **Always**]
    A -->|uses cached data| B[Child]
    A -->|uses cached data| C[Child]
    A -->|uses cached data| D[Child]

style A fill:#4CEC8C
style B fill:#FF9A74
style C fill:#FF9A74
style D fill:#FF9A74