diff --git a/src/reference/changes.rst b/src/reference/changes.rst index 61f1fb1e1b..ee4d3916ba 100644 --- a/src/reference/changes.rst +++ b/src/reference/changes.rst @@ -131,6 +131,43 @@ Supported Python versions The minimum supported Python version is now 3.12. +Automatic Broadcast Expiry +^^^^^^^^^^^^^^^^^^^^^^^^^^ + +Broadcasts automatically expire (i.e, are deleted) once they are no longer +required by upcoming tasks. + +This means that if you try to re-run a task from the previous cycle, its +broadcasts will likely have been expired. In Cylc 8.6.0, we have pushed back +the broadcast expiry limit to make it easier to re-run tasks from the previous +cycle. For more information, see +:ref:`the user guide `. + +Another consequence of broadcast expiry is that broadcasts made to historical +cycles (behind the broadcast expiry point) will expire instantly. +The ``cylc trigger --on-resume`` option was added to allow us to broadcast to +a cycle before triggering the task: + +* Pause the workflow. +* Trigger the task using the ``--on-resume`` option + (the task will not run until the workflow is resumed). +* Issue the broadcast. +* Resume the workflow (the task will now run). + +At Cylc 8.6.0, automatic broadcast expiry is suspended while the workflow is +paused which simplifies this process: + +* Pause the workflow. +* Issue the broadcast. +* Trigger the task (no special option required). +* Resume the workflow. + +Note the order of the broadcast and trigger operations has swapped to the +logical order. + +The ``--on-resume`` option has been removed. + + ---------- Cylc 8.5