When scrolling using Grid Virtualization, Queries are executed twice

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Unplanned

Last Updated: 15 Feb 2021 09:10 by ADMIN

Imported User

Created on: 02 Apr 2014 16:55

Category: Grid

Type: Feature Request

When scrolling using Grid Virtualization, Queries are executed twice

When scrolling data in a grid using the virtualization scrolling option, the query to fetch the next section of data will occur twice. It does not happen for every query, but it does happen all the time regardless of scrolling fast or slow.

5 comments

Stephane

Posted on: 27 Dec 2020 17:20

In my case, the SQL queries are complex, it takes 2 to 3 seconds before getting the response. So, the transition between pages can't be smooth anyway. It generates too much traffic (and our customers have low bandwidth) and uses too much CPU on the server.

We have the same problem with the DropDownList, so, we rewrote the kendo.throttle function (cf https://www.telerik.com/forums/virtualization-and-scrolling-too-much-server-calls). I'll have to find a new workaround for the grid to have only one server call when the user stops to scroll.

ADMIN

Tsvetomir

Posted on: 24 Dec 2020 10:42

Hello,

The prefetch requests are a mandatory part of the implementation of the virtualization of the grid. They are needed for having a smooth transition between the pages as well as better UX for the users that use the respective application.

In order to reduce the number of requests sent, you can increase the page size. Can you share the concerns around using a prefetch function? Does it cause a delay on your application or does it generate too much traffic?

Best regards,
Tsvetomir
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Stephane

Posted on: 17 Dec 2020 17:30

An old request still relevant...
Requests are executed too many times, we should have an option for differents loading modes. We would like a mode where there is no prefetch, and when the page be loaded only when the user stops scrolling.

Shelomo

Posted on: 17 Jun 2014 07:33

Im also experiencing this issue. We are coming from slickgrid which cancels all the pending requests and you can feel the gird works much more smoothly. I think the Kendo UI team should reconsider fixing this.

Andrew

Posted on: 03 Apr 2014 13:06

I reported the same issue in Feb 2013 (ticket 654012). 

The Kendo UI Support response follows:

***

"We are aware of this behavior, however the logic which virtualization follows is optimized for specific speed of scrolling and since there are pending requests and pre-fetching requests strategy, duplicate requests can happen under specific conditions when there are pending requests which take too long time and you scroll to areas which refer the same page.

I assure you that our Dev team did its best to optimize the virtualization as much as possible and there is nothing I can suggest (to) you to troubleshoot that case."

***

In my case, I was also experiencing duplicate requests nearly every time - unless the scroll speed was very slow.

Unfortunately, I'd suggest this has been put in the category "Won't fix".