Nginx creates more connection than poolsize, backlog to redis

[Kumar Nikhil]

I am using https://github.com/openresty/lua-resty-redis#connect method and keepalive()
i have kept pool size to 200 and backlog 20, Still it creates 2000 connections to redis during a load test.
is_connected, err = client:connect(REDIS_SERVER1,REDIS_PORT,{ pool_size = 200, backlog = 10})

What could be the reason for more number of connection from nginx to redis ? How can we control or restrict it ?