## What is Key Visualizer?

Key Visualizer helps you analyze your Spanner data access patterns.

Understanding data access patterns is critical for following
[schema design best practices](https://docs.cloud.google.com/spanner/docs/schema-design) and avoiding hotspots. Hotspots
occur when too many requests are sent to the same server which saturates the
resources of the server and potentially causes high latencies.

With Key Visualizer, you can diagnose common issues that cause hotspots. It
generates visual reports to show how data is accessed in your database. In
addition, you can identify usage patterns over time that are difficult to
understand otherwise.

## What's next

- Learn how to [Access Key Visualizer](https://docs.cloud.google.com/spanner/docs/key-visualizer/getting-started).
- Find out how to [use Key Visualizer to explore a heatmap](https://docs.cloud.google.com/spanner/docs/key-visualizer/exploring-heatmaps).
- Understand the [patterns you might see in Key Visualizer
  heatmaps](https://docs.cloud.google.com/spanner/docs/key-visualizer/patterns).
- Read about the [metrics you can view in a heatmap](https://docs.cloud.google.com/spanner/docs/key-visualizer/metrics).
- Learn about other tools for [monitoring an instance](https://docs.cloud.google.com/spanner/docs/monitoring-cloud)
- [Watch a video](https://www.youtube.com/watch?v=3QHGhnHx5HQ) about using Key Visualizer to diagnose an issue in a similar product.