Approval Notifications Loading Slow?

Summary

Assignment change notifications are loading really slow

Content

Hi All,

Context: We have around 50k employees migrated with almost 40 years of history. This makes around 1 million assignment records uploaded in the system.

Problem: We are facing an issue whenever any assignment update is made like Change Location, Change Manager, Promotion etc. the approval notification takes a lot of time to open. Most of them they open after 3-4 minutes. We have already raised SR and tried a few work arounds like removing the employment term data model etc. No luck till now.

This issue is happening on the NUX notifications. If we switch back to classic notifications it works fine and is fairly fast (10-20 seconds).