Gallery scrolling performance issues

[pmcgurn01]

I'm hoping there's some kind of planned performance improvement work on the gallery control, but posting this, in case there isn't.

At present, the gallery control is incredibly clunky/laggy when scrolling any faster than what I'd consider to be "unreasonablly slow".  The behavior is 

1. I scroll
2. The rows move up
3. There is a huge empty whitespace for about 1-2 seconds
4. The white space fills up as the elements render
5. Repeat process

I will note:

• It doesn't matter if I bind the gallery to a local collection or directly to the data source.   Since my data source (Azure SQL) is too large to be cached to a collection, I'm limited to direct binding anyways.
• It's reproducible in web player (Chrome browser) and mobile (iPad app)
• I am using ThisItem to bind all data to controls in the gallery.  At this point, I have 8 controls total in the template row, which are a mix of images (2 icons) and labels (6 of those).
• It seems to be completely unrelated to latency in the network.  I can verify this by watching the troubleshooting console, and the lag isn't tied to any network calls, though I do see those happen at each 100 rows of data or so.
• I can reproduce this on other data sources that I am caching to a local collection on app OnStart, where I see this empty whitespace when I scroll fast enough to where the gallery would need to render more than ~5 rows at a time.  In that case, the datasource is cached to a local collection, and that gallery only has 5 labels in the template row.

I'm attaching a video of this behavior.  While the lag you see might be "acceptable", it's not a great user experience on any platform. I understand that the gallery is probably working as designed for keeping resource utilization low on mobile devices, however, since this can be reproduce on mobile, too, I'm asking that Microsoft improve this. 

[Anonymous]

Web client performance is fine for me, my issue regarding this was with the Windows client.

[FLOWPA]

If my 2 cents can be of help to you @pmcgurn01 and others with similar problems:

---

@pmcgurn01 wrote:

This forum is infuriating.  Every time I post, it loses the original and I have to re-write it.  Having to save my original content to a notepad just in case I hit the "unexpected error occurred" failure makes me post less.

Rant on that, over.  Now on to my reply.

It's definitely not caused by network latency.  I profiled it in Chrome, and there's a clear lag in scroll performance even when not calling for data from the data source via network.  So that rules out the cached local collection vs. data source binding conversation entirely.  My DS and use case for this screen are too big to cache anyways.

The screen I'm testing this with has a gallery that contains 10 UI elements in the template, where 7 are DS-bound and 3 are static images/labels.  Of the 7, 5 are labels and 2 are read-only radio buttons.  The app checker shows no warnings related to anything on the app other than warnings on accessibility text.

So, I really hope Microsoft is working on improving this performance, because it's unusable at scale and making me reconsider my decision to use the PowerApps platform to deploy apps within my company.

---

If both, PowerApps gallery and the forum are giving you issues, then your computer might need some tuning and maintenance. I have no performance problems at all.

Forum: I have no issues with the forum using Chrome. Keep in mind that computers and browsers need a regular cleanup including malware removal, unwanted software, addons, cache, etc. I would install a dedicated development browser, and only use it for PowerApps and related development tasks. Choose a browser (Chrome, Firefox, Edge), do a fresh install, don't install addons unless necessary.

PowerApps Gallery: I have large galleries with nested galleries, and other formulas for on-the-spot calculations, and the performance is good. 

Try testing it on another computer or try a different browser. You'll notice the difference. Make sure the computer is powerful enough, at least with a 4 cores processor and at least 16GB of RAM. 

If you running it on a laptop, make sure that battery settings are not set to saving battery, but set to max performance. 

If you have performance issues with the browser and with PowerApps, the best thing you can do, it's to have a dedicated development computer, without any unneeded software, and with recurring cleanups. 
Make sure your computer is modern and with a good amount of RAM.

I have 32GB of RAM and have no performance issues, even though my computer is already outdated. But I keep it clean. PowerApps runs smoothly and the forums gives me no issues.

[ChrisSullivan]

For the annoying post problem. If you just type "This is my Post" and then go back and edit the post it works. 

[pmcgurn01]

Memory and battery have NOTHING to do with this.  FWIW, my machine is a high end Macbook Pro, and neither CPU or Memory are ever an issue. 

Multiple end users of apps published by multiple app builders would indicate a shortcoming in the platform, not our well-equipped computers and mobile devices.  So it works fine for you?  Congrats, the rest of us suffer.

[FLOWPA]

---

@pmcgurn01 wrote:

Memory and battery have NOTHING to do with this.  FWIW, my machine is a high end Macbook Pro, and neither CPU or Memory are ever an issue. 

Multiple end users of apps published by multiple app builders would indicate a shortcoming in the platform, not our well-equipped computers and mobile devices.  So it works fine for you?  Congrats, the rest of us suffer.

---

If you have a high-end machine, there could be another problem causing the gallery to perform poorly or getting stuck. 

For example, some databases or spreasheets API have a limited amount of queries per second, or similar restrains. One of my galleries, had a sub-gallery, and it was getting stuck when loading. It was taking forever to load. Then, I found that my queries were getting blocked by the data source. It was my fault, not my computer, not Microsoft.

Another cause of performance issue, it's inefficient formulas or the way the app is designed.

I would recreate the gallery from scratch within a new app, and start adding few formulas gradually, and testing performance. Any software has bugs, and our job is to find resolutions to create a final product that works as intended. We can't just blame it on Microsoft.

Since your browser is giving you issues as well, there must be something going on with your system, or there is a compatibility issue. 

[PaulD1]

I see (and have always seen) the same in galleries in Power Apps. If you scroll more than a few rows you will get a blank space and a brief pause before the rows will then appear. It typically takes a little less than a second for the rows to appear (assuming there are no complex formulas or data calls involved),  but it is certainly noticeable and I would say your gif is typical of the behviour I see.

If your gallery is based on a delegable data call you will also get a delay once you hit row 100 as that triggers Power Apps to go get the next 100 rows, then when you hit row 200 you get another delay and so on. I think this is preferable to the alternative of bringing in all the records up to the delegable limit (so no pause when hitting record 100) but having the initial records render more slowly (because more records are being fetched), but you can use FirstN to get that behaviour if you wish (though you then can't scroll beyond the delegable limit unless you add code to perform some sort of 'paging'.

Fortunately this doesn't really bother me too much (though it would be nice to see it improved and would leave users with a better impression of the product) and it is just one of those cons to balance against the pros when deciding if Power Apps is the right tool for a specific scenario.

[cwebb365]

Running into this as well. The gallery control does not work well when using more than 3 - 5 controls it seems in a template item. Trying to create grid like views, it starts to get quickly worse over time. If you only show 5-10 records it works fine, but you start showing more rows it starts to tank performance in not just scrolling but selecting rows etc. 

Data Table would be epic for this use case and it's performance is great, but it's very limited as I need multi select capabilities that it doesn't provide. If only we could get a few updates to that it would work great. Tons of columns, grid view, and it's fast and resizes etc. 

I'm starting to look into this custom canvas grid control. But haven't the slightest clue on how these work, but if I can figure it out I'll pass on the knowledge, but this would be perfect if I can get it working with multiple dataset lookups for conditional formatting etc. Create canvas app dataset component in Microsoft Dataverse - Power Apps | Microsoft Docs

Anyway, I know it's a year later and problem still seems unsolved. Guessing you went another route or had to change design considerations on some stuff. Anyway, if you have found any solutions since, let me know!

[cwebb365]

And to everyone suggestion data source/ delegation etc. the original post said he tested with local collection :P. Anyone can reproduce this, create a gallery, shrink the template size down to like 20, add a 20 height horizontal container throw in a 20 height label, copy and paste the label like 10 times. Connect it all to just a basic Thisitem.id field from the data source with 200 records. Try to scroll. It def. lags :P. 

[dave-jorgensen]

At this point no solution, gallery issues still there (note two years since this was raised here). I created a ticket with microsoft once I came on board, and nothing. At this point, you are following the best path for performance - use datatables. I haven't created dataset components yet, just normal components. Definitively going to install that one you linked to and try it out! Thanks so much for posting that. Great case for why we should keep cases alive for years.

[TomLanz]

We were running into something very similar with one of our galleries this week. We ran around in circles trying to figure out why items weren't loading up faster. In the end, we determined that the issue was actually that the gallery  was slow to recalculate it's height. When we changed the gallery to a fixed height, then things scrolled super smooth. 

Not sure if that's applicable to your case, but I thought I'd throw it out there.