Hi, your problem is, that you have added 1.2 million contacts to your system, and every single contact joined 3 segments and got triggered 4-5 campaigns.
Are you using all the 1.2 million contacts? If so, you just need to invest in a better infracstructure.
If not, then better delete incative contact’s campaign and segment history fro time to time.
Check if the regular cleanup command helps:
If not, then you’ll need some scripts, that delete old entries.