Handle "LOADING Redis is loading the dataset in memory"

Hi,

When a slave is first being connected to a master it needs to load the entire DB, which takes time. Any command that is send to that slave during this time will receive a LOADING Redis is loading the dataset in memory response.

I think we should handle this and retry the command (Maybe even to a different node within the same slot).

@luin thoughts?

[shaharmor]

Hey @luin , I just encountered this issue again, and I think we should see how we can fix it.

[hktalent]

@shaharmor Mac OS:

rm -rf /usr/local/var/db/redis/*
brew services restart redis
redis-cli -n 4 FLUSHDB