Add per-tenant TSDB cardinality status API endpoint#7332
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CharlieTLe wants to merge 3 commits intocortexproject:masterfrom
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Add per-tenant TSDB cardinality status API endpoint#7332CharlieTLe wants to merge 3 commits intocortexproject:masterfrom
CharlieTLe wants to merge 3 commits intocortexproject:masterfrom
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Expose TSDB head cardinality statistics through a new /api/v1/status/tsdb endpoint, enabling users to identify which metrics, labels, and label-value pairs contribute the most series. This follows the existing UserStats fan-out pattern: ingester calls Head.Stats(), distributor aggregates across the replication set (dividing replicated counts by RF), and an HTTP handler serves JSON with an optional ?limit=N parameter. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com> Signed-off-by: Charlie Le <charlie_le@apple.com>
Document the new TSDB cardinality status endpoint in the HTTP API reference, including query parameters, example request/response, and field descriptions. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com> Signed-off-by: Charlie Le <charlie_le@apple.com>
End-to-end test that starts a single-binary Cortex cluster, pushes series with varying cardinality, and validates the TSDB status API returns correct series counts, metric name breakdowns, and limit truncation. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com> Signed-off-by: Charlie Le <charlie_le@apple.com>
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| limit := int32(10) | ||
| if v := r.FormValue("limit"); v != "" { | ||
| if n, err := strconv.Atoi(v); err == nil && n > 0 { | ||
| limit = int32(n) |
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Incorrect conversion between integer types High
yeya24
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Mar 6, 2026
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Thanks for the PR!
I think this worth a design proposal as it is not a simple API and we need to think about how to extend it long term. Several questions I have:
- Is
/api/v1/status/tsdbthe right API to support? Or we should have a more specific API for cardinality analysis. Even though the endpoint is the same but I see you are using different response format compared to what Prometheus has https://prometheus.io/docs/prometheus/latest/querying/api/#tsdb-stats. - What fields should we support?
memoryInBytesByLabelNamelike this might make it hard to extend to long term storage - Is it the right thing to expose the API via distributor? Worst case this API could impact writes and this is what I want to avoid. Exposing via Querier seems safer and we can utilize even Query Frontend caching in the future
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Summary
/api/v1/status/tsdbendpoint that returns per-tenant TSDB cardinality statistics (series count by metric name, label value counts, memory usage by label, series count by label-value pair, min/max time)Test plan
TSDBStatusgRPC methodTSDBStatusaggregation logicTestTSDBStatus) that starts a single-binary Cortex cluster, pushes series with varying cardinality, and validates correct series counts, metric name breakdowns, label stats, and limit truncation🤖 Generated with Claude Code