Pooling

CachingPool <<<<<<<<<<<

pool_cached A gauge of the number of connections cached.

WatermarkPool <<<<<<<<<<<<<

pool_waiters A gauge of the number of clients waiting on connections.

pool_size A gauge of the number of connections that are currently alive, either in use or not.

pool_num_waited A counter of the number of times there were no connections immediately available and the client waited for a connection.

pool_num_too_many_waiters A counter of the number of times there were no connections immediately available and there were already too many waiters.

SingletonPool <<<<<<<<<<<<<

conn/fail A counter of the number of times the connection could not be established and must be retried.

conn/dead A counter of the number of times the connection succeeded once, but later died and must be retried.