Investigate app memory usage

[bengtan]

There was one instance around Feb 3rd 2020 where low_memory warnings were correlated with the app crashing. See https://hippware.slack.com/archives/C2V6L53TQ/p1580781852115000?thread_ts=1580745379.101800&cid=C2V6L53TQ

We should investigate memory usage and/or try to improve it (if not too much work). For example:

• Examine how much memory the app uses.
  • Maybe post memory usage metrics in the memory_warning bugsnag?
• See if we can release some memory when we get the low memory warning.
  • Somehow fire the javascript garbage collector (if possible?)
• Other stuff?

---

(Original Post)

Bit worried about the app being killed by the OS if it uses too much memory.

This has been mentioned (by me) as a possible cause of #4037.

[bengtan]

There was one instance around Feb 3rd 2020 where low_memory warnings were correlated with the app crashing. See https://hippware.slack.com/archives/C2V6L53TQ/p1580781852115000?thread_ts=1580745379.101800&cid=C2V6L53TQ

We should investigate memory usage and/or try to improve it (if not too much work). For example:

• Examine how much memory the app uses.
  • Maybe post memory usage metrics in the memory_warning bugsnag?
• See if we can release some memory when we get the low memory warning.
  • Somehow fire the javascript garbage collector (if possible?)
• Other stuff?

[aksonov]

App uses about 220Mb. But... Occasionally found memory leak today, by pressing menu button, so now it uses 254 after many many menu button taps. I will investigate more

[bengtan]

FYI, when I (very briefly) looked at this last year, I looked for a component which could retrieve the amount of memory being used by the app and found react-native-vitals.

https://github.com/robinpowered/react-native-vitals

YMMV.

[aksonov]

Very useful article: https://blog.swmansion.com/hunting-js-memory-leaks-in-react-native-apps-bd73807d0fde

[aksonov]

I did many measurements of app memory usage, but they are very very unstable and not reproducible. Sometimes the difference is bigger, sometimes - smaller, it probably depends from garbage collector.

However I found some evidence where most leaks are placed - from difference snapshot I see many objects are from React Navigation. I was not able to find own app memory leaks - after I reduced code I still saw memory leaks...

Similar issue: react-navigation/react-navigation#7078
And some leaks could be from React itself: facebook/react#14732

Even if I don't use react navigation, just tap to see fullscreen map and then tap again to return to previous state I see very small but memory leaks:

I see similar issue here:
and here facebook/react#16138

Measurement results:

======= reduced, without navStore

before:
237mb

After 10 menu open/close attempts

246mb

2. Before:
250mb

254 after

3. 246/249

===== reduced, with navStore
1. before:
246mb

After 10 menu open/close attempts
261mb

2. Before:
229.5

After:
242mb


3. Before:
272

After:
282

4. Before
256Mb

After:
261Mb

==== latest master
Before
249Mb

After 
260Mb

[bengtan]

Some bugsnags with memory stats have been posted (after 4891 was merged).

It's reporting memory usages of 126MB, 89MB, 35MB, 41MB when the low memory warning was triggered. These numbers seem ... okay?

https://app.bugsnag.com/hippware/tinyrobot-1/errors/5e6be5dcb90f3d00176c4caf