Connection.destroy() may kill wrong session (on different node)

[sergburn]

Current (3.4.0) implementation of connection.destroy() tries to kill ongoing query by opening side connection and executing KILL <thread-id>. It relies on the assumption that this new connection will reach the same server instance if the connection is open by IP rather than DNS.

Quote from connection.js:

        // relying on IP in place of DNS to ensure using same server
        const remoteAddress = this.socket.remoteAddress;
        const connOption = remoteAddress ? Object.assign({}, this.opts, { host: remoteAddress }) : this.opts;

However, if the IP points to a Load Balancer with NAT, this new connection may be opened to another DB instance and then wrong session will be killed.

This behaviour must be optional, please add a corresponding parameter to ConnectionConfig. (I could work on a PR, if wanted)

[sergburn]

I just realized that threadId is also used to index active connections in pool.js, and thus it's possible that connections open to different servers via load balancer could clash with each other, correct?