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. 

[cwebb365]

Curious on the batch classify. I basically do this in my app I use the PCF grid control on, they can multi select drag and drop and classify using bulk edit window. 

[OscarSotoCL]

Hi, yes five minutes for 800 rows its too much. but i understand now you are using an SQL OnPrem, over an OnPremise Data Gateway  i guess.  About the Sql View, are you using some indexes or pimary keys.   A few years ago we tested query SQL from PowerApps, and all the results was very Slow, so we start to work our data in Sharepoint list, with their corresponding indexed columns, and using delegated querys.

[WheresWally]

Similar idea although I can't do drag and select, that'd be nice:

[cwebb365]

Odd, I use Azure SQL and it runs great using 2000+ Only time I had issues was bad table indexes once some tables got larger but those were quick fixes. 

[cwebb365]

I feel the pain on working to get that gallery to look, line up and work to only have it run like crap 🤣🤣. 

[cwebb365]

I'm trying to export my grid solution and import it to another environment to see if it works fine. IF so I'll put a download link and you can try it if you like as is. I was gonna do a video explaining the code edits and stuff I made but meh, at least I can get this out and people can use what I've figured out and used and it's worked well for a couple years at this point without issues. 

[OscarSotoCL]

Yes, SQL On Prem Connections using On Prem Data Gateway depends on the customer internet connection, not always reliable. Using PowerApps with AzureSql is different and tends to be quicker than OnPrem SQL, at least on my experience with my customers

[WheresWally]

I go via a gateway to get to the SQL server. The queries are fast enough and they are being place into collections. Something about adding the datacard in the canvas and having that actually load all those rows from the collection is really slow. I'll investigate if it's heights or something.Thanks for thinking it through with me. 

[WheresWally]

hyped for this, appreciate you taking the time. 

[OscarSotoCL]

About that points

1. dataflow from SQL server on prem into a dataverse table

2. Query another SQL view in the powerapp directly - with user selected date filter variables.  (collection1)

3. Query the dataverse table from step 1 with the same date range. (collection2)

4. Use addcolumns to left join collection1 onto collection2. (collection3)

5. Use collection3 as the Item source for the gallery

How are you running the 4 point. maybe this is the part that slows the query.  are you using a forall for one collection and a lookup to get the data from the other collection, to get the columns?