1443567 - Improve HAR export performance

Status: NEW

(DevTools :: Netmonitor, enhancement, P3)

Description

[Jan Honza Odvarko [:Honza] (always need-info? me)]

This is follow up for bug 1434855

HAR exporter [1] is currently disabling redux actions when fetching data (to export) from the backend. This makes the export a lot more faster since it's avoiding batching timeouts generated by batching middleware [2]. 

The issue is that disabling redux actions results with the store not being updated. We should try to rather disable the batching middleware and ensure that the store is updated. However, updating the store might represents perf penalty, and so more analysis/testing needed.

Honza

[1] devtools/client/netmonitor/src/har/har-exporter.js
[2] devtools/client/netmonitor/src/middleware/batching.js

Comment 1

[Jan Honza Odvarko [:Honza] (always need-info? me)]

See also this comment:
https://bugzilla.mozilla.org/show_bug.cgi?id=1434849#c5

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Here is a profile of exportHar subtest:
  https://perfht.ml/2tl8Joo
It highlights FirefoxDataProvider.updateRequest. I'm wondering if the usage of Object.assign is an issue here. Do you know if FirefoxDataProvider has to be immutable? Isn't it redundant with what will happen in the reducers?
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Honza