The DataNode adds a log to report its progress during addToReplicasMap execution.

Datanodes do not print logs when addToReplicasMap is just started, so we will not be aware of its progress, or even wait up to 4 hours for a large cluster. This is very confusing.

A cluster is as follows:

The optimized result is as follows:

(Because Scan thread is ForkJoinPool, so the printing may be repeated, but it will affect the overall progress of the presentation
)