What is the best way to read live tag values from the ignition gateway into third party platforms? Specifically I am trying to read live values of all the tags at once (~100k). Currently I am using webdev, which takes ~25 seconds per request.
The canonical way to do this is either to enable the "Expose Tag Providers" setting in the OPC UA server, which exposes all your Ignition tags as OPC UA tags for other clients to consume:
Ignition's OPC UA Server | Ignition User Manual, or to use MQTT.
Either is going to be a whole lot more efficient than direct polling from Webdev.
Are there any guidelines for compute/memory recommendations when reading tags from the OPC UA Server? Is there a limit to how many tags can be subscribed to at once without the gateway being overloaded?
I don't think we've done any testing like this.
I'd expect that you could subscribe to all 100k without much issue as long as you're actually using a subscription and not repeatedly reading them..