Heatmap patterns for document keys

This page shows examples of patterns that you might see in a Key Visualizer heatmap. These patterns can help you troubleshoot specific performance issues.

Evenly distributed usage

Heatmap showing evenly distributed reads and writes

If a heatmap shows a fine-grained mix of dark and bright colors, then reads and writes are evenly distributed throughout the database. This heatmap likely represents an effective usage pattern for Firestore.

Sequential keys

Example heatmap showing a diagonal hot band

A heatmap with a single bright diagonal line can indicate a database that uses strictly increasing or decreasing keys. Sequential keys are an anti-pattern that can create hotspots. To learn more about hotspots, see the best practices page.

When hotspotting, you might observe corresponding elevated latencies when you compare a Ops/s metric with a latency metric.

Sudden traffic increase

Heatmap showing a sudden increase

A heatmap with a key range that suddenly changes from dark to bright indicates a sudden spike in load. If Ops traffic increases faster than Firestore can auto-scale resources, you might see corresponding elevated latency metrics.

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