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. 

[v-monli-msft]

Hi @pmcgurn01 ,

How many records are there for your data source? 

About how to improve performance in PowerApps, you can also refer to:

https://docs.microsoft.com/en-us/powerapps/maker/canvas-apps/performance-tips

https://powerapps.microsoft.com/en-us/blog/performance-considerations-with-powerapps/

Regards,

Mona

[pmcgurn01]

@v-monli-msft 

I had a whole nice reply typed up, but every time I post something in this community, it fails the first time with an "unexpected error, contact your system administrator", and if I didn't copy what I wrote before submitting, it's lost.

Answers to your reply:

1. Record count has no bearing on this issue.  I can reliably reproduce it on both cached local record sets of 259, or Azure SQL record sets in the thousands.
2. I've already followed every possible performance recommendation in both of those articles, prior to posting my original issue.

[Spencer]

I have the same performance issue and my gallery items are based on a local collection.  Scrolling is worse than what is picture in the above video example.  Has anyone found a solution for the scrolling issue?

[MaxEgn]

I also am having this issue. 

It is not based on number of records at all as I only have about 45 right now.  

I have also tried the same data in a local collection to see if that made a difference, and it did not. 

[pmcgurn01]

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.

[sspencer]

I have found that if there are any processes running in the back ground or from a timer the scroll latency increases considerably.  Even with no processes in the back ground and less than 100 records in a collection performance lags when scrolling.  My clients were using Access database front ends linked to SQL databases and the scrolling performance was much better.

[pmcgurn01]

Access DB's having better performance than Azure SQL is pretty tragic.

[dave-jorgensen]

Is Microsoft doing any work on this issue? Makes for a very poor user experience when user scrolls and then has to wait several seconds for the controls to render

[jared_simmons]

Bump on this thread. The issue is all over the place. Especially worsens with nested galleries... apps are nearly non-functional. Both CPU and Memory consumption jump through the roof on local machines while scrolling.

I'm caching all data into a local collection like everyone here... There is no pattern suggestion or dev best practice to alleviate this. This is a performance bug with the platform as a whole.

Need MS eyes on this please.