---
title: "Tag search | Grafana Tempo documentation"
description: "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."
---

> For a curated documentation index, see [llms.txt](/llms.txt). For the complete documentation index, see [llms-full.txt](/llms-full.txt).

# 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/service.name/values` 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.

## Solutions

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](../../configuration/#overrides) block of your Tempo configuration to a value as high as 50MB.