This option allows user to change the number of ranges to stream in
batch per stream plan.
Currently, each stream plan streams 10% of the total ranges.
With more ranges per stream plan, it reduces the waiting time between
two stream plans. For example,
stream_plan1: shard0 (t0), shard1 (t1)
stream_plan2: shard0 (t2), shard1 (t3)
We start stream_plan2 after all shards finish streaming in stream_plan1.
If shard0 and shard1 in stream_plan1 finishes at different time. One of
the shards will be idle.
If we stream more ranges in a single stream plan, the waiting time will
be reduced.
Previously, we retry the stream plan if one of the stream plans is
failed. That's one of the reasons we want more stream plans. With RBNO
and 1f8b529e08 (range_streamer: Disable restream logic), the
restream factor is not important anymore.
Also, more ranges in a single stream plan will create bigger but fewer
sstables on the receiver side.
The default value is the same as before: 10% percentage of total ranges.
Fixes#14191Closes#14402
dad5caf141