Skip to content

Draft changelog: Merge Queue testing capacity metrics #314

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
mintlify wants to merge 1 commit into
base: main
Choose a base branch
from
Open

Draft changelog: Merge Queue testing capacity metrics #314

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
21 changes: 21 additions & 0 deletions changelog/2026-08-19-merge-queue-testing-slot-metrics.mdx
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,21 @@
---
title: "Merge Queue: New testing capacity metrics"
description: "The Merge Queue Prometheus endpoint now exposes separate gauges for active CI testing slots and PRs currently in the testing phase, making batching-aware capacity tracking straightforward."
slug: merge-queue-testing-slot-metrics
date: 2026-08-19
category: Merge Queue
type: update
---

**Two new gauges on the Merge Queue Prometheus endpoint make it easy to track CI capacity separately from the number of PRs under test.**

Previously, testing activity was reported as a single number, which conflated CI slot usage with the number of PRs in flight when batching was on. The endpoint now exposes:

- **`mq_testing_slots_active`** — number of active CI slots currently in use. A batch counts as one slot, so this maps directly to CI concurrency.
- **`mq_prs_testing`** — number of PRs currently in the `TESTING` state. With batching enabled, this can exceed `mq_testing_slots_active` because several PRs share a slot.

Use `mq_testing_slots_active` for CI utilization alerts against your configured concurrency, and `mq_prs_testing` when you want to see how many PRs are being validated at once.

Both metrics carry the standard `repo`, `branch`, and `queue_type` labels and are available at `GET /v1/getMergeQueueMetrics` alongside the existing point-in-time gauges and 1-hour window metrics.

See [Merge Queue metrics](/merge-queue/administration/metrics) for the full metric reference and example PromQL queries.
6 changes: 6 additions & 0 deletions changelog/index.mdx
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -8,6 +8,12 @@ rss: true

### August 2026

<Update label="August 19, 2026" tags={["Merge Queue"]}>
**[Merge Queue: New testing capacity metrics](/changelog/2026-08-19-merge-queue-testing-slot-metrics)**

The Prometheus metrics endpoint now exposes `mq_testing_slots_active` and `mq_prs_testing` as separate gauges, so batching-aware CI capacity tracking is straightforward.
</Update>

<Update label="August 11, 2026" tags={["Flaky Tests"]}>
**[Flaky Tests: Asana ticketing integration](/changelog/2026-08-11-flaky-tests-asana-ticketing)**

Expand Down
Loading