I've looked at your code in Scripting (or wherever it's at) for the end of map stats and it is really cool. I don't particularly want to go that route for a few reasons, most of all because if someone leaves before a map is finished then they lose any progress they have made since then.
I myself ran into an issue of SQL transactions bogging down the game, and I have implimented a periodic update for Common Infected kills. Any Common Infected kills that a player gets are stored in a temporary array, and after a set period - 90 seconds by default - a single SQL query is made with the total amount for the past 90 seconds and the array is cleared. It also updates when a player disconnects and when a Safe House is reached, so that kills and points are not lost.
If you do have issues, let me know, but hopefully you shouldn't.
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