[OH3] Defining Rules in Main UI increases CPU Load

[gdolfen]

I have a problem with high cpu usage in M2 and M3.
I figuerd out that the reason are rules which are configure over main ui.
I started with 4 rules in a *.rules file with a cpu usage of 1%. In main ui they always stay on "IDLE" after migration them to main ui by copy the generated code by the code view everything was fine, but the logs was full with ERRORs "No pre-parsed script found for e3dc-2". So I deleted the line "// context: e3dc-2" from the code and the log disappears, but the cpu was increased up to 5% per rule and the state stays always on "RUNNING".
Here is my rule code:

triggers:
  - id: "0"
    configuration:
      itemName: E3DC_Extern
    type: core.ItemStateChangeTrigger
conditions: []
actions:
  - inputs: {}
    id: script
    configuration:
      type: application/vnd.openhab.dsl.rule
      script: |
        // context: e3dc-2
        var Number negativeValue = E3DC_Extern.state as Number
        var Number positiveValue = negativeValue * -1
        E3DC_String3.postUpdate(positiveValue)
    type: script.ScriptAction

It seemed that the rule is parsed every time, because every 5 seconds (5 seconds update period of item E3DC_Extern) I got the log error. Maybe preparsing the rule after saving it in main ui makes the trick.

[Boby71]

+1; same for me on OH3.0.0 stable:
After defining many DSL rules on my system, I run into errors like "java.lang.OutOfMemoryError: Java heap space" which leaves the system completely unresponsive after a while.

It seems to happen when the rule(s) are triggered often, by a constantly changing value (e.g. a temp sensor). The rules seem to take too long to run (e.g. a few seconds for a simple postUpdate) and when there are enough rules running and new ones started upon, the system runs out of memory. So there is a bug in DSL rules processing when they have been defined via the GUI.

[JohannesPtaszyk]

I got this issue as well. My hue dimmer switch state is changed almost instantly, but the rule for it takes like 10 seconds to execute.
My raspberry pi goes from 1% usage to 28% upon execution and it takes 10 seconds.
1 Core goes up to 100%

[JohannesPtaszyk]

I moved my setup to a Raspberry Pi 4 4GB and now everything is working fine.

[kaikreuzer]

Thanks for the report. I have created #2057 for it, it would be great if you could test a snapshot, once that PR is merged and available in the distro!

[gdolfen]

@kaikreuzer: I testet your change with the latest snapshot build an the problem is gone. Thanks a lot for your fix!