dbstats

type PoolStats struct {
	// Idle counts open connections not currently in use. Used counts those
	// checked out. Constructing counts those being opened.
	Idle, Used, Constructing int32

	// MaxConns is the configured limit on open connections. A count of
	// connections in use means nothing without knowing the limit.
	MaxConns int32

	// Acquires counts every successful request for a connection. EmptyAcquires
	// counts how many had to wait for one to become available. CanceledAcquires
	// counts how many gave up waiting before getting one. Read the last two
	// together: as the pool degrades, EmptyAcquires falls while CanceledAcquires
	// rises, so a deteriorating pool looks better if only the first is watched.
	//
	// EmptyWaitSeconds is the total time spent waiting (successful requests
	// only). It includes opening new connections when necessary, so the full
	// network handshake, TLS negotiation and authentication. Pools routinely
	// replace old connections, so a baseline of wait time here is normal setup
	// overhead, not queue contention.
	Acquires, EmptyAcquires, CanceledAcquires int64
	EmptyWaitSeconds                          float64
}

type PoolStatter interface {
	PoolStats() (PoolStats, bool)
}