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Performance impact of large Item Lists on form loading
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I would like to raise a performance concern related to forms containing large Item Lists.

My analysis shows that server side callbacks and business rule requests include the current state of the entire form, including Item List rows and columns, even when the executed rule does not reference the Item List.

In my tests, a form with approximately 40 Item List rows generated requests of around 1 MB, while the same form with approximately 400 rows generated requests of around 5.5 MB. As a result, simple business rules that normally execute in around 50 ms (or lower) can take around 500 ms. Since many requests are executed sequentially during form initialization, this significantly increases form loading time.

I also observed a significant server side impact. Continuously opening only 6 to 8 invoices with large Item Lists was sufficient to reach 100 percent CPU utilization on an application server with an Intel Xeon Gold 6140 CPU and 8 processors.

I reported this behavior to WEBCON Support. It was reproduced on versions 2025.2.1.259 and 2026.2.3.145. According to Support, sending the complete form state is intentional, there is currently no option to limit the transferred data and no workaround other than avoiding very large Item Lists. The topic is treated as product development rather than a defect.

From my perspective, this is difficult to justify to large enterprise customers running complex, multi country processes, where several hundred Item List rows are not necessarily exceptional.

I would therefore like to ask WEBCON to take a closer look at this area and consider increasing the priority of improvements related to Item List serialization, callback processing and server side handling of large form states.

I would also appreciate feedback from other customers and partners who have encountered similar performance issues.

MVP

I've run into the issue myself and in one case it completely killed the browser. Ok, the workflow instance had 17k rows and the compressed response body was of somewhere larger than 50mb. :)

It will be interesting to see, what kind of impact our feedback made. On the other hand I would guess, that we will never now it.
https://community.webcon.com/forum/thread/8164

Best regards,
Daniel