Patch() vs UpdateIf() - what are the differences, pros and cons

[davidstone]

I realise almost this same question has been asked before, and answered by @Mr-Dang-MSFT, but I'm looking for a broader answer than the specific example in that post.

I understand that Patch changes a single record, while UpdateIf can update a whole set of records.

I want to understand the performance difference of one vs the other on the same task. So patching a single record, or using UpdateIf with a condition that will match a single record.

In my case, Patch was generating an etag mismatch, but UpdateIf just works. So ultimately it's a question of whether using UpdateIf is going to compromise performance compared to using Patch?

Bonus question: I'm not sure why Patch wouldn't work for me, I'm sure the same function was working a few weeks back. I followed some related forum posts which suggest doing a refresh prior to the patch - didn't fix it. A potential quirk in how I'm using it is that I collect all my data locally, then have a button inside a gallery displaying that collection, which does a patch back to the original datasource (SharePoint List) filtered on the matching ID.

[Mr-Dang-MSFT]

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@davidstone wrote:

I want to understand the performance difference of one vs the other on the same task. So patching a single record, or using UpdateIf with a condition that will match a single record.

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Both ForAll(Patch()) and UpdateIf() will be heavy actions in terms of performance. 

But it is sounding like it's a non-starter for you to use Patch(). What's the formula you're using with it that is causing an ETAG mismatch?

[davidstone]

It's:-

Patch(Events, LookUp(Events, ID = ThisItem.ID), { Approved: "Yes" })

So basically the gallery lists events which are currently not approved. Each row has a button that let's you approve with one click.

[davidstone]

Also I'm not using a ForAll with my patch - it only needs to update the one record clicked on.

[Mr-Dang-MSFT]

@davidstone I'm looking into the ETAG mismatch issue.

Can you run these steps:

• Create a blank app
• Insert a list screen and connect it to an SP list
• Patch a change to a record in the SP list
• Observe the ETAG mismatch error and get a session id

Repeat steps, but with UpdateIf instead of Patch and get a second session id.

[davidstone]

Hmm, the plot thickens...

I just did as you said, created the app, and the error didn't occur. The only difference from my app is using a list-view pointed to a local collection, so I added a screen in the app for that too... still no error.

So to get a reliable example of the issue I went to the original app that triggered this post, and un-commented the line that was causing the issue... no issue!

This is, at least, consistent with what I had thought, which is that original code had been working when I first put it in about a month ago.

I guess from here I should just look out for it, and if I see an etag mismatch, get my session ID and let you know?

Thanks.

[luuminhvuong93]

@Mr-Dang-MSFT   Hi Brian , sometimes I faced issues with patching updates to sharepoint lists (Etag mismatches ) too,

Wonder whether you know what might be the root cause, and how to avoid this in PowerApps,