Ignition - High CPU Usage in MS SQL DB

We are using Ignition 8.1.23 version.
I have a serious problem with my ignition instance and that their SQL server was hanging on 100%.
The Ignition gateway and the database server are in different AWS instances.
CPU Suddenly, the CPU usage increments and everything in my server falls down, Data logging stopped in DB like that. Then I have restarted the Gateway/ AWS instances and the CPU usage decrements again and I still cannot find why.
This has happened multiple times in the last 2 weeks.