KNOWLEDGE BASE

Error "hyper_execute_query: 0 Cannot allocate ### bytes of memory: exceeding allocation limit" Accessing Published View or Querying Extract on Tableau Online


Published: 19 Nov 2019
Last Modified Date: 25 Nov 2019

Issue

When attempting to load a published view or query an extract on Tableau Online, the following error occurs:

Data Source Error
Unable to connect to the data source.
Try connecting again. If the problem persists, disconnect from the data source and contact the data source owner.
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[###] hyper_execute_query: 0 Cannot allocate ### bytes of memory: exceeding allocation limit of ### bytes for local transaction memory limit
DataServiceFailure

Environment

  • Tableau Online
  • Hyper

Resolution

See the below options to reduce the amount of extracted data and optimize the query to use less memory resources on Tableau Online. 

Option 1 - Add Filters and Aggregation When Creating the Extract

When you create an extract, use filters to exclude data that you don't need, and aggregate data for visible dimensions to minimize the size of the extract file, and increase performance. Also, ask yourself if you need all of the records in a data source, or if you can limit the extract to a representative sample. For more information, see Extract Your Data.

Option 2 - Hide Unused Fields

Hidden fields are not included when you create an extract. Use the Hide All Unused Fields option to hide unnecessary fields before you create an extract. This makes the extract smaller, which improves performance. For more information, see Hide or Unhide Fields.

Option 3 - Optimize Extracts 

The Compute Calculations Now option materializes calculations in your extract, meaning that certain calculations are computed in advance and their values are stored in the extract. Depending on the complexity of the calculations used in your extract, this can potentially speed up future queries. For more information, see Materialize Calculations in Your Extracts

Option 4 - Create Efficient Calculations

Consider rewriting calculations for improved performance. For more information, see Create Efficient Calculations.

Cause

Tableau Online has a 20GB RAM limit. If that limit is exceeded the query will be terminated.
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