src/Db/Pgsql/PgClient.php
private function getLeastBusyConnectionOld() : pgConnection
    {
        if (count($this->connections) === 0) {
            // try to spin up another connection to return
            $conn = $this->createNewConnection();
            if ($conn === null) {
                throw new Exception('There are no connections. Cannot find least busy one and could not create a new one.');
            }

            return $conn;
        }

        $min = reset($this->connections);

        foreach ($this->connections as $connection) {
            // if this connection is idle - just return it
            if ($connection->getBacklogLength() === 0 && $connection->getState() === pgConnection::STATE_READY) {
                return $connection;
            }

            if ($min->getBacklogLength() > $connection->getBacklogLength()) {
                $min = $connection;
            }
        }

        if (count($this->connections) < $this->maxConnections) {
            return $this->createNewConnection();
        }

        return $min;
    }
private function getLeastBusyConnectionOld() : pgConnection
    {
        if (count($this->connections) === 0) {
            // try to spin up another connection to return
            $conn = $this->createNewConnection();
            if ($conn === null) {
                throw new Exception('There are no connections. Cannot find least busy one and could not create a new one.');
            }

            return $conn;
        }

        $min = reset($this->connections);

        foreach ($this->connections as $connection) {
            // if this connection is idle - just return it
            if ($connection->getBacklogLength() === 0 && $connection->getState() === pgConnection::STATE_READY) {
                return $connection;
            }

            if ($min->getBacklogLength() > $connection->getBacklogLength()) {
                $min = $connection;
            }
        }

        if (count($this->connections) < $this->maxConnections) {
            return $this->createNewConnection();
        }

        return $min;
    }
Get least busy connection, with idle state or at least with minimum queued queries count
@return pgConnection
@throws Exception
@deprecated
@see getLeastBusyConnection()