emqx4.3/changes/ce/fix-10407.en.md

Improve 'emqx_alarm' performance by using Mnesia dirty operations and avoiding unnecessary calls from 'emqx_resource_manager' to reactivate alarms that have been already activated. Use new safe 'emqx_alarm' API to activate/deactivate alarms to ensure that emqx_resource_manager doesn't crash because of alarm timeouts. The crashes were possible when the following conditions co-occurred:

• a relatively high number of failing resources, e.g. bridges tried to activate alarms on re-occurring errors;
• the system experienced a very high load.