Slow Expression Tags

Version 8.1.39

I was working on a customer's server when I noticed that expression tags were taking 30-40 seconds to initialize or to update their values.

I tried creating memory and reference tags and those updated immediately.

All of these tags were on my own tag group which had the default settings of 1000ms and a new name to differentiate from "Default".

Remoting into the server showed the cpu was consistently around 40% and the memory allowed for Ignition is 12 of 32GB. Ignition is only using a max of 9GB.

I am curious to know how expression tags execute differently from other types. And I want to know if anyone has seen and/or remedied this behavior before.

Some other information:

  • there are 2 other tag providers that have about 50k tags each
  • otherwise there around 10k tags among 10 other providers
  • this gateway has the MQTT transmission module

If it's still happening get a thread dump and post it here.

Ok here it is. Thanks

Ignition-JOPV9903_thread_dump20241206-143716.json (555.7 KB)

Sorry, use this one. This is while it was executing.

Ignition-JOPV9903_thread_dump20241206-144026.json (580.4 KB)