Using ProCal / ProCal-Track V6 with a Remote Server / Over a VPN

With the introduction of a SQL back end, the Procal software suite is much more resilient to slower networks.

This has opened up the possibility of hosting the main database and data storage at an off site location, sharing a single database between multiple databases or data hosted in the cloud.

However, there is a fundamental difference between a server connected on the LAN vs one located remotely.

Each transaction against the database requires a message to be sent, and in the case of a search (I.e. looking for an instrument record) a return of data in the form of a record, of which there may be many depending upon the search.

On a LAN the time to send/receive a message is very small, typically < 1 ms on a modern network.

When connections have to traverse external networks extra delays are added as data is passed from your computer to the router, to your ISP, then to the servers ISP, back to the remote router and to the server.

This is known as latency.

In Transmille’s experience even a dedicated high speed line (> 30 mbs up/down) has at least 10 times the latency of a local connection, typically more, this increases the round trip time of a search upwards of 50 ms per record/search result from 1 - 2 ms.

To measure latency to your server (please note that this is not retrieval of data, simply a round trip message to confirm the presence of the server) you can use the Ping command provided by the windows command prompt with the following command.

ping <ip address or server / server name>

The effect of this latency is seen when populating easy to use lists that contain easily searchable data, for example performing a search for all multimeters in your database or where a drop down list of customers is available.

This can cause the software to appear to ‘hang’ while data is retrieved and presented to the user. For example, data that would have taken less than 100 ms to be retrieved from a server locally (50 customers x 2 ms maximum) will take over 2 seconds over a connection with even 50 ms of latency, 25 times longer.

While this may not sound like much, larger databases will contain thousands of records, so when searching for a list of > 200 unique records this extra delay becomes considerable. 

Transmille are actively developing solutions to assist with customers that wish to work with remote servers, however this work is in development and behind other new features in priority.

As such, working with remote servers is not yet officially supported by ProCal and ProCal-Track due to the extra delays and less than optimal user experience. Customers are advised that using ProCal with a remote server is at their own risk and offer no performance guarantees or cover errors that may be due to this extra latency/network instability.

To find out more information or to receive a free trial of ProCal please contact us.