[release/13.6] Reduce dashboard CPU under sustained metric ingestion

[aspire-repo-bot]

Backport of #20736 to release/13.6

/cc James Newton-King (@JamesNK)

Customer Impact

In Aspire 13.6, long-running AppHosts with sustained metric ingestion can consume steadily increasing dashboard CPU even under a fixed or idle workload. A reported 15-project AppHost reached approximately 70% of one core after 6.8 hours, with significant SQLite churn and database growth.

Testing

Passed 59 targeted SQLite metrics and persistence tests, excluding quarantined and outerloop tests. The source PR also validated the before/after ingestion benchmarks and smoke-tested all 12 existing metrics-query benchmark cases. Backport PR CI is currently in progress.

Risk

Low. The change is localized to SQLite metric-retention cleanup, preserves the existing retention limit and cascading deletes, and adds focused coverage for retention, database reopening, and transaction-failure recovery. It makes no public API or database schema changes.

Regression?

Yes — introduced in 13.6 with SQLite-backed telemetry in #18924.

[github-actions]

🚀 Dogfood this PR with:

⚠️ WARNING: Do not do this without first carefully reviewing the code of this PR to satisfy yourself it is safe.

curl -fsSL https://raw.githubusercontent.com/microsoft/aspire/main/eng/scripts/get-aspire-cli-pr.sh | bash -s -- 20747

Or

• Run remotely in PowerShell:

iex "& { $(irm https://raw.githubusercontent.com/microsoft/aspire/main/eng/scripts/get-aspire-cli-pr.ps1) } 20747"

[github-actions]

Tests selector

Selects the full PR test matrix + all PR-gated jobs (ALL) — run-all fallback: 'benchmarks/Aspire.Dashboard.Benchmarks/TelemetryRepositoryMetricsBenchmarks.cs' is neither Layer-1-owned nor matched by a Layer 2 rule

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Selection computed for commit d69560a.

[github-actions]

Retrying the failed CI jobs for this pull request from the CI run attempt. The rerun is being tracked in the rerun attempt.

[aspire-repo-bot]

✅ No documentation update needed.

Step 5 branch taken: excluded → base_branch_is_release, head_branch_is_backport, title_release_prefix, body_backport_marker

Triggered signals: none (signal_count = 0; excluded overrides the docs_optional recommendation regardless).

Exclusion reasons (from .pr-docs-check/signals.json):

• base_branch_is_release — PR base is release/13.6.
• head_branch_is_backport — head branch follows the automated backport-bot naming pattern.
• title_release_prefix — title is prefixed [release/13.6].
• body_backport_marker — PR body states "Backport of Reduce dashboard CPU under sustained metric ingestion #20736 to release/13.6".

This PR is a backport of #20736 to release/13.6, created by aspire-repo-bot[bot]. Per the workflow's backport-exclusion rule, documentation for this change belongs on the original forward PR (#20736) against the default branch, not duplicated here. No docs PR is drafted for this backport.