How to reproduce:
- Create a struct that contains an array of Transforms
- Create a DataTable of this struct
- In a new Blueprint, generate large amount (let’s say 5-10k) of Transforms, e.g. by For Loop in Construction Script and add all the generated transforms into a public array variable (to be able to Copy the values from editor)
- Place the blueprint into a scene and in its details panel right click on the transform array variable (it should have many generated transfom values inside) and click Copy.
- Create a new row in the DataTable and right click → Paste the values into it.
- This action will cause a major lag, in my case freezing my whole PC for 1-2 minutes. During the freeze, RAM usage peaks incredibly high, it takes almost all of my 8GB memory.
When pasting these values to e.g. a text file, there is no lag at all. Why it behaves differently with DataTable and causes this big freeze? The freeze will appear also when re-opening the saved DataTable, but no freeze when we close it. Why does it need so much RAM to only paste/display the values? This looks like some memory leak…
BTW. I’m not the only one experiencing the major slowdown when having many values in blueprints: Storing large lists (arrays) in blueprints? - Blueprint - Unreal Engine Forums