NRIV is number range. It’s a general table for all number range.
Now what’s number range buffer?
Number range buffer is used to enhance the performance during assigning numbers. Instead of fetching numbers each time from database (db), it just access from buffer. Only when buffer is empty, its refilled from database. (NRIV table)
What’s number range server?
If the number range interval which we want is not present in the buffer or we can say number stock is exhausted, then the number range buffer must fetch new numbers from the NRIV table from the database. It’s called number range server. Another additional workprocess (WP2) is required for this. It runs on same server on which WP1 runs.