milvus: [Bug]: Investigate the Cpu Usage on small instance when the system is idle

Is there an existing issue for this?

• I have searched the existing issues

Environment

- Milvus version:
- Deployment mode(standalone or cluster):
- MQ type(rocksmq, pulsar or kafka):    
- SDK version(e.g. pymilvus v2.0.0rc2):
- OS(Ubuntu or CentOS): 
- CPU/Memory: 
- GPU: 
- Others:

Current Behavior

https://github.com/milvus-io/milvus/issues/22571 https://github.com/milvus-io/milvus/issues/17942

We will see many similar issues that said cpu is high after data insertion.

I have some wild guess about it, but we need to verify on how to reproduce:

1. Single collection with enough data -> Create a 2c8G Standalone and insert 8GB memory into it, do some search and leave it for at least 1 day, see the data growth and cpu usage(should be less than 0.5 core)
2. Multi collection -> Create a 2c8G Standalone and create 100 collections, see what will happen
3. Multi collection - >Create a 2c8G Standalone and create 100 collections, each collection insert 10000 entities and trigger index build

Expected Behavior

CPU usage is below 1 CPU

Steps To Reproduce

No response

Milvus Log

No response

Anything else?

No response