sync tikv config

[bufferflies]

Enhancement Task

Config supports region-max-size property. This value should only be set by file not by api.

[bufferflies]

The operator will be cancel if it's started time duration excceed than timeout time(10m).
I think one operator includes moving a 10Gb's region step will be can be calculate by: the generator sst + transfer sst + apply sst. And the generator sst will cancel if retry time excceed than 5 and the transfer sst has fluid control（100Mb/s).

[bufferflies]

I think the timeout value should be conservative. The value can use the below formula：
duration=10m+ （regionSize/Mb /100Mb/s) *(receiving_count+sending_count)*5 =10*60+ regionSize*6*5/100s=600+ regionSize*0.3
if region size is 10g, the duration should be ： 600+10*1000*0.3=3600s=2h

[lhy1024]

There may be some operators buildup that prevents other operators from executing properly.

[BusyJay]

What if the region size is not initialized before the operator is created?

[bufferflies]

The size of one region will be 1MB if region reports without size. So if the real size of region is bigger like 1GB not 1Mb, the operator will be cancel because of timeout.

[BusyJay]

How about building up feedback mechanism? If a region is really replicating a snapshot, then it should be canceled with cleanup. Otherwise there will be too many concurrent snapshots and run into chaos before other operators get in.