[Yandex Cloud documentation](../../../index.md) > [Yandex DataLens](../../index.md) > Troubleshooting > Data source timed out

# [Yandex DataLens] Data source timed out

`ERR.DS_API.DB.SOURCE_ERROR.TIMEOUT`

Query execution time exceeded for the data source.


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DataLens limits the query execution time on the source to 80 seconds.

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To fix this error:

* Optimize the data in the source.
* Reduce the number of complex expressions with nested aggregations.
* Reduce the number of fields in the dataset.
* Create calculated fields at the dataset level instead of fields at the chart level.