plugin_metrics had only a PK on id, so every host-detail, full-metrics, and
dashboard-widget load sequentially scanned the entire time-series table — which
grows by (sources × resources × sample cadence), so the host views got slower
over time (operator-reported "blocked/slow" loads). monitor_results was already
indexed, so the uptime aggregation wasn't the bottleneck.
Add two composite indexes matching the hot query shapes:
- (source_module, resource_name, recorded_at) — history range scans, fleet/
widget queries, and the 'host:%' sub-resource prefix.
- (source_module, resource_name, metric_name, recorded_at) — the latest-value-
per-metric group-by/self-join.
Model __table_args__ + core migration 0023. Integration lane validates the
migration via `alembic upgrade head`.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_016Jg27rgypiW2efULXJDtMC
bvandeusen
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