This is documentation for the next version of Tempo. For the latest stable release, go to the latest version.

Open source

Tag search

An issue occurs while searching for traces in Grafana Explore. The Service Name and Span Name drop down lists are empty, and there is a No options found message.

HTTP requests to Tempo query frontend endpoint at /api/search/tag/ would respond with an empty set.

Root cause

The introduction of a cap on the size of tags causes this issue.

Configuration parameter max_bytes_per_tag_values_query causes the return of an empty result when a query exceeds the configured value.


There are two main solutions to this issue:

  • Reduce the cardinality of tags pushed to Tempo. Reducing the number of unique tag values will reduce the size returned by a tag search query.
  • Increase the max_bytes_per_tag_values_query parameter in the overrides block of your Tempo configuration to a value as high as 50MB.