Open Slot With No Current Processes / Threads (%) - Percentage that ta is waiting for new incoming requests.
Keepalive (read) - Numbers of existing connections (live).
Waiting for Connection - Percentages connections awaiting processing start.
This can be interpreted in a few ways.
1. The app spends less time waiting for a connection. This could mean that there aren't many connections or the connections come through, request finishes quickly and then it disconnects thereby leaving many open slots available. i.e. a checkout line at the store where the cashier processes items quickly and efficiently.
2. Connection comes in, sees that too many connections are already being handled and time out.
3. Not too much traffic going through.
I'm inclined to think its either 1 or 3.