[Performance] Opening search for the first time on a big account is causing the app to hang massively

[hannojg]

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What performance issue do we need to solve?

In a customers meeting the customer was trying to open the search for the first time in NewDot. It caused the app to hang up, and it was a very bad user experience (see the recording):

https://github.com/user-attachments/assets/99d97430-9545-475a-afca-7d0c5b5d1437

What is the impact of this on end-users?

User perception of the app is very bad, as it's super laggy, basically not usable (the browser even warns that the app is hanging).

List any benchmarks that show the severity of the issue

The customer shared a profile trace with us:

Firefox 2024-07-25 10.42 profile.json.gz

(note: the trace also contains other test cases as well)

The customer had ~15k reports loaded in onyx when these tests were conducted, although in focus mode only 6 chats were displayed.

Proposed solution (if any)

None yet, I will go through the profile and see what can be optimised, what exactly caused those lags.

List any benchmarks after implementing the changes to show impacts of the proposed solution (if any)

not available yet

Platforms:

Which of our officially supported platforms is this issue occurring on?

• [ ] Android: Native
• [ ] Android: mWeb Chrome
• [ ] iOS: Native
• [ ] iOS: mWeb Safari
• [x] MacOS: Chrome / Safari
• [ ] MacOS: Desktop

Version Number: v9.0.11-5 Reproducible in staging?: not tested Reproducible in production?: yes Email or phone of affected tester (no customers): customer Logs: See performance file Notes/Photos/Videos: See attached video Expensify/Expensify Issue URL: n/a Issue reported by: @hannojg Slack conversation: https://expensify.slack.com/archives/C05LX9D6E07/p1721919928992729

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[melvin-bot[bot]]

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[hannojg]

cc @sakluger (feel free to assign me as I (or someone from my team) will work on this ticket!)

[marcaaron]

Curious what is happening with this especially to see if it is related to large numbers of reports (seems likely as there are 15k reports). Gonna assign myself in case @hannojg needs any assistance.

[sakluger]

No updates

[sakluger]

No update

[hannojg]

A large part of this hanging is due to us building the search options the moment we open the search page:

• https://github.com/Expensify/App/blob/4bac1000e36d0a8ba5fba945e87053d7b8cf2ef2/src/pages/ChatFinderPage/index.tsx#L78-L91

I am thinking about how to solve this here, by moving the operations in a first step to a separate thread/web worker:

• https://expensify.slack.com/archives/C05LX9D6E07/p1723454316012939?thread_ts=1723209631.007999&cid=C05LX9D6E07

[hannojg]

I just opened a PR hat shows a PoC for using web workers for running the search, which will unblock the main thread:

• https://github.com/Expensify/App/pull/47432

I am now seeking approval on this new technical design here.

(Note: I am OOO for the rest of the week and will continue next week Monday 19.08)

[sakluger]

Moving to weekly for now since Hanno is out until Monday.

[hannojg]

Can you please also assign @chrispader? he will work on that as well (Chris please comment 🫶 )

[chrispader]

Commenting for assignment :)

[sakluger]

Thanks for helping, @chrispader. I'll be OOO for the next week. Hopefully we'll have some more details from the investigation when I return!

[hannojg]

We were able to reproduce the bigger lags when running on a virtual machine, where the hardware is more constraint than on our recent MacBook Pro models directly. (note: we tested against a recent adhoc build that contained some search improvements).

The thing that takes the most time when opening the search page / chat finder page is:

• calling createOptionsList
• calling getSearchOptions (on the results of createOptionsList)
• calling triggerUnreadUpdate also took ~1-2 seconds

We will come up with solutions for improving the performance of these functions (in the current single threaded architecture). (Some of these solutions might blend with the solutions we are working on here)

[sakluger]

@hannojg any updates on this investigation?

[sakluger]

No updates - seems like we are focusing on improving search speed first. There is a WIP PR for that (https://github.com/Expensify/App/pull/48652), hopefully we'll get back to this one after that.

[sakluger]

No updates.

[marcaaron]

What's the latest on this one?

[hannojg]

We were able to get another, cleaner, sample of that problem here which relates to creating the options (which causes the lag):

• https://github.com/Expensify/App/issues/46593#issuecomment-2387772633

I am sure now that we have a cleaner recording we can come up with good solutions to make this faster!

[sakluger]

No updates.

[sakluger]

No updates.

[sakluger]

No updates

[sakluger]

No updates

[sakluger]

No updates