696558 - "Forget about this site" is incredibly slow

Status: RESOLVED DUPLICATE of bug 648232

(Toolkit :: Data Sanitization, defect)

Description

[Joe Drew (not getting mail)]

I just did a "Forget about this site" from the History manager for a site I'd just visited, and Firefox hung for about 2 minutes, seemingly writing to my disk at 2 MB/s. My places.sqlite is 115 MB.

Comment 1

[Marco Bonardo [:mak]]

which version of firefox?

May even not just be Places, Forget about this site invokes this method
http://mxr.mozilla.org/mozilla-central/source/browser/components/privatebrowsing/src/nsPrivateBrowsingService.js#573
that does the following things:
- clear browsing history (this is partly async)
- evict entries from cache service
- clear image cache
- removes cookies
- removes plugin data
- remove downloads
- remove password
- remove permissions
- remove content preferences
- clear indexedDB

Now, as for Clear Recent History being painfully slow, 99% of these cases are not Places, but are due to:
- clearing cache
- spawning instance of each of the plug-ins you have to check if we can clear their data

If you could gather some timestamp from the above function and check which of those things is slow that'd greatly help.

Comment 2

[Marco Bonardo [:mak]]

PS: we may even add telemetry for those timeframes!

Comment 3

[Dietrich Ayala (:dietrich)]

Joe, see this for a way to isolate just the Places-related activity:

https://bugzilla.mozilla.org/show_bug.cgi?id=694687#c1

Can you try that and see if the hang occurs? If it doesn't, then it's one of the many non-Places things which that code does.

Comment 4

[:Gavin Sharp [email: [e-mail]]]

Without more info, I'm just going to assume this was bug 648232.

Comment 5

[monperrus]

This bug is still present in FF 42. The freeze happens when the site to be forgotten happens many times in places.sqlite. 

For instance, trying to forget about www.google.com completely freezes FF.

A workaround is to temporary remove places.sqlite before forgetting, and/or to manually delete the urls in places.sqlite. See https://support.mozilla.org/en-US/questions/1004992

Comment 6

[Marco Bonardo [:mak]]

(In reply to martin.monperrus from comment #5)
> A workaround is to temporary remove places.sqlite before forgetting, and/or
> to manually delete the urls in places.sqlite. See
> https://support.mozilla.org/en-US/questions/1004992

Both of these are very bad ideas and will bring to dataloss long term.

Btw, there are various reasons for the slowdown, and we have other bugs tracking the same issues. We need to go through the whole history removal code and fix its performance. But first we need Places to enter the Firefox Quality effort, since at the moment noone is assigned to its maintenance/improvement.

Comment 7

[Marco Bonardo [:mak]]

you can track bug 871908 and bug 734643 for related work.