Mass category change causes memory and CPU usage spikes, often leading to tab hang and crash

[zdimension]

Describe the bug
Changing the category for a lot of operations, from the search page for example, causes the tab to eat up a ton of memory and CPU and the whole page slows down to a halt and often crashes.

To Reproduce
Steps to reproduce the behavior:

1. Get a list of operations (e.g. search for something so you get more than, say, 20 or 30 operations in the results)
2. Select one operation, click Select All, so all operations are selected
3. Change the category

Expected behavior
It changes the category

Screenshots

It looks like when a "change category for N operations" job is sent to the server, the server processes it operation by operation, but every time an operation is updated remotely, the list of operations is re-created from scratch on the client, but somehow the old objects aren't GCed fast enough (so the RAM usage increases), and the re-creation of that list eats up the CPU.

Also, if after changing the category, I switch to the budget page (showing categories for the year) the same thing happens; for each operation that is updated (around 1 per second), the list is refreshed and the page is slowed down.

Desktop (please complete the following information):

• OS: Windows 10
• Browser: Chrome 111

[Crash--]

Hello @zdimension, thanks for the issue.

I just take a look at how we handle the category change:

• we map on the transactions and we set the new category https://github.com/cozy/cozy-banks/blob/master/src/ducks/transactions/TransactionCategoryEditor.jsx#L32-L34
• then we saveAll() aka we send one _bulk_docs request to the server
• and then, when the server respond, our data library does a lot of stuff:
  • point1: update the in memory data and replay the in memory queries
• but at the same time, server will send us ONE message (via the websocket) per updated document. And when we received ONE message, we do again the point1.

There is a room of improvements here. The good thing is that there is only one way to handle that change, so if we are able to fix one issue, we'll fix the others 💪

On firefox, I can see the CPU usage, but the GC seems to be working fine. I'll try on a slower device and with a chromium browser.

GitHub

cozy-banks/TransactionCategoryEditor.jsx at master · cozy/cozy-banks

A Banks Aggregator on Cozy. Contribute to cozy/cozy-banks development by creating an account on GitHub.