knowledge(performance): add job queue reliability guidance

community/knowledge/performance/job-queue-on-hold-does-not-stop-running-work.md

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+---
+bc-version: [all]
+domain: performance
+keywords: [job-queue, on-hold, cancellation, in-process, long-running, stop-request]
+technologies: [al]
+countries: [w1]
+application-area: [all]
+---
+
+# Putting a job queue entry on hold does not stop its current run
+
+> Contributions welcome — open a PR to refine or extend this article.
+
+## Description
+
+The On Hold status prevents a job queue entry from starting again, but it does not cancel a run that is already in process. A long-running handler continues until it completes, fails, reaches a cancellation point implemented by the application, or its session is stopped externally.
+
+## Best Practice
+
+Use On Hold to pause future scheduling. When a long-running operation must support graceful cancellation, store a separate application-owned stop request and check it between bounded units of work. Exit only at a point where completed work and the checkpoint are consistent; use administrative session termination only when graceful cancellation is impossible.
+
+See sample: `job-queue-on-hold-does-not-stop-running-work.good.al`.
+
+## Anti Pattern
+
+Polling the job queue entry's Status field from inside its handler and expecting a change to On Hold to cancel the active run. The status controls scheduling, not cooperative cancellation, so the handler can continue processing despite the operator's action.
+
+See sample: `job-queue-on-hold-does-not-stop-running-work.bad.al`.