Reduce the block cache miss when balancing the hot region

[rleungx]

Feature Request

Describe your feature request related problem

When the store is under high read pressure, we will move some hot region to the new store when we enable the auto scaling in order to implement the load balance. And we find this kind of operation may cause some cache miss. It will have some impact on the system performance.

Describe the feature you'd like

Maybe we can use a special label to fill block cache when ingesting SST.

Describe alternatives you've considered

Teachability, Documentation, Adoption, Migration Strategy