Class-C downlink scheduling

ChirpStack Network Server
1

Any reason why the downlink schedule interval needs to be there? I saw it’s 1 second by default
Also, does this scheduler do some round-robin on the queued items across multiple devices? I think not; in which case the application needs to keep it’s own queue if retries need to be done and some device lost connectivity. (probably better to attempt another device first)

2

It is how often the database get queried for Class-C downlinks. E.g.

for {
    // query class c downlinks
    // sleep(schedule interval)
}