High-priority scenarios

By default, tasks of all scenarios are processed by shared workers in the order they arrive. If the platform has many scenarios and the load is high, tasks of a critical scenario may wait for processing along with the rest.

To have a scenario's tasks processed before regular ones, you can mark the scenario as high-priority. A separate pool of workers in the cluster is allocated for it: these workers drain the priority queue first and only then pick up everything else.

info

Scenario priority is a separate mechanism from priority sending in mailings. Scenario priority speeds up processing of tasks (node execution), while priority sending speeds up message delivery in channels. They work independently and complement each other.

When to use

Assign high priority to scenarios where processing delay is critical for the business — for example, scenarios that send messages immediately after a user action.

How to enable

To activate the option, open the scenario settings and enable the High priority toggle:

Then save the scenario. No service restart is required — the new value takes effect immediately.

You can change the priority at any time: turn the toggle off and save the scenario. The change affects only new tasks — profiles that are already in the scenario continue processing with the previous priority.

What happens when enabled

• Dedicated processing. The scenario's tasks are processed by dedicated workers on the hosts that the platform administrator configured for priority tasks. While high-priority tasks are present, these workers do not pick up regular ones. When there are no high-priority tasks, the workers help with regular ones — the throughput of regular scenarios is not reduced.
• Priority sending in mailing nodes. In all Channels nodes of the scenario, the High priority toggle is automatically enabled and locked — you cannot turn it off manually. In regular scenarios, the toggle is available for manual control. Toggling the scenario priority on and off does not overwrite the value the user set in a campaign: it is restored as soon as the scenario becomes regular again.

Limitations

• Priority does not guarantee processing or delivery time. It sets the order in the queue but does not override the rest of the platform's limits: sending limits, channel queues, and mailing speed settings work as usual.
• Priority message sending is not available in all channels. Details — in Trigger mailing.
• Campaign processing inside a scenario is synchronous: a worker is occupied with it entirely, from recipient selection to publishing to the queue. Priority speeds up how quickly a worker gets to the campaign, but within the sending itself, the stages common to all campaigns run in the general order.
• A node failure does not lead to loss or reprocessing of profiles: unfinished tasks are automatically passed to other cluster nodes.