983437 - Delay FHR pruning until the screen is off

Status: RESOLVED INVALID

(Android Background Services Graveyard :: Firefox Health Report Service, defect)

Description

[Michael Comella (:mcomella) [NI reported issues only: ex-Mozilla]]

There is the possibility of FHR pruning causing ANRs in the browser because it may lock the DB and any subsequent event recordings will have to wait on this operation to finish.

We can mitigate the effects of this by delaying FHR pruning until the screen is off, rather than firing it in onPause. Additionally, a slightly faster-to-implement solution is to add a time delay after onPause before starting FHR pruning (but this is more likely to run into coincidental issues).

Some more extreme solutions, if this is found not to work are:
  * Drop recorded events (or store them in SharedPrefs until the DB is free)
  * Have a background thread recording FHR events, which will get blocked when the DB is locked, rather than the whole browser.

Comment 1

[Richard Newman [:rnewman]]

I think you need a delay *and* a power check. Otherwise hitting the power button twice in quick succession will be just as bad as hitting Home and then switching back to Fennec.

A rephrasing of the background thread idea: writes should be queued, not block.

Comment 2

[JDev]

Assumes the screen will go off at some point which is not 100% guaranteed (though likely very rare for it not to)

Comment 3

[Michael Comella (:mcomella) [NI reported issues only: ex-Mozilla]]

Not actively working on this.

Comment 4

[Michael Comella (:mcomella) [NI reported issues only: ex-Mozilla]]

We don't do FHR anymore.