What causes the return value of a dimension to be null?

The return value of a dimension being null can occur when there is a retention of only a limited number of data values in a query. This typically happens in scenarios where the data set is compacted or filtered down to a specific range or subset that does not include the information related to that dimension. If the query is structured to only retrieve a certain number of data points, and those points do not cover the full time frame or conditions needed, it can lead to situations where the dimension returns no applicable results.

In contrast, improper formatting of the metric data refers to issues with how the data is presented or structured, which would not inherently lead to a null return but rather could cause errors or misinterpretations of the data. Low data volume collected over time typically would provide some values assuming there is data available for the specified conditions, just potentially fewer values than desired. Lastly, insufficient permissions would generally result in access denial errors rather than a null return of dimensions, as the system would indicate that the data cannot be accessed at all rather than returning a null value for the queried dimension.