Feature Request: option to warm up bufferpool with warming reads from primary to replica #13205
Description
Feature Description
When reparenting to a replica, if that replica has recently been restarted, it will have a cold bufferpool, and for bufferpool-reliant workloads, this means a performance hit for a few minutes until the bufferpool of the new primary warms up.
As such, it would be great to have the ability to mirror a certain percentage of SELECTs from the current primary to the replicas at the vtgate level, so that when time comes to reparent, the replicas will have a warmer bufferpool than before and not suffer this consequence.
Use Case(s)
When rolling restarting, we restart first one replica, then another, then reparent, and then restart the previous primary. We wait a bit between restarting the replicas and reparenting to warm up the bufferpool, but with this feature, we would wait less.