bcquality/microsoft/knowledge/performance/store-scheduled-task-id-to-avoid-duplicate-tasks.md

bc-version	domain	keywords	technologies	countries	application-area
all	performance	task-scheduler scheduled-task taskexists duplicate-task createtask guid	al	w1	all

Store the scheduled task ID to avoid duplicate tasks

Contributions welcome — open a PR to refine or extend this article.

Description

Every call to TaskScheduler.CreateTask creates a new scheduled task and returns its unique GUID. Repeating setup or lifecycle code without retaining that GUID can create multiple tasks for the same logical work, consuming scheduler capacity and running the work more than once.

Best Practice

Persist the GUID returned by CreateTask at the same scope as the logical task. Before creating a replacement, parse the stored GUID and call TaskScheduler.TaskExists; create and store a new task only when the previous task no longer exists. TaskExists checks one GUID, not whether an equivalent codeunit is already scheduled, so callers that can schedule concurrently still need serialization around this check-and-create sequence.

See sample: store-scheduled-task-id-to-avoid-duplicate-tasks.good.al.

Anti Pattern

Calling TaskScheduler.CreateTask every time initialization, login, setup, or another repeatable path runs while ignoring its return value. Each invocation creates another independent task even when an equivalent task is already pending.

See sample: store-scheduled-task-id-to-avoid-duplicate-tasks.bad.al.