On Thu, 11 Aug 2022 at 15:13, Paul Zühlcke <[email protected]> wrote:
> This is awesome! Thanks for working on it. > What happens if the disk cache clearing hasn't finished when user starts > Firefox again? Will they still be able to use the cache? > Good question. The cache folder is renamed, prior to deletion, so we can be sure the background task has exclusive access to it. A new instance would start with a completely new cache folder, even if the background task hasn't finished deleting the old one yet. PS. Sorry for forgetting the subject in my previous email 🙂 > On Thu, 11 Aug 2022 at 14:50, Valentin Gosu <[email protected]> > wrote: > >> Hi everyone, >> >> As Bug 1705676 - Investigate purging HTTP disk cache using >> backgroundtasks (out-of-process) >> <https://bugzilla.mozilla.org/show_bug.cgi?id=1705676> is getting closer >> to landing, I wanted to give everyone a heads-up about this change and the >> reasoning behind it. >> >> We have a non-default setting in the History settings preferences panel >> where you may choose to "Clear History when Firefox closes" - which sets >> the privacy.sanitize.sanitizeOnShutdown pref. If the Cache checkbox is also >> checked that sets the privacy.clearOnShutdown.cache pref to true. >> When both of these prefs are true CacheObserver::ClearCacheOnShutdown() >> will return true, which will cause Firefox to clear the HTTP disk cache >> during shutdown. This will block shutdown for however long this takes. If >> the user has a slow disk, or the user is on Windows and something is >> blocking the deletion of those files, this will trigger a shutdown hang >> making Firefox crash. This also leads to a bad user experience as trying to >> start Firefox again during this time will show the "Firefox is already >> running message". Eventually a crash dump is produced. Bug 1356853 and bug >> 1682899 are caused by this specific issue. >> >> In order to avoid these shutdown hangs, we have introduced a new >> mechanism that uses background tasks >> <https://firefox-source-docs.mozilla.org/toolkit/components/backgroundtasks/index.html> >> to delegate the deletion of the cache to a separate process that may >> outlive Firefox. Even if this process is unexpectedly killed (as may happen >> during shutdown), we spawn it again after Firefox starts up to clean up any >> directories that may be left. >> >> *The plan is to enable this on Windows Nightly in the next few days to >> evaluate if this does indeed work as expected. Assuming it doesn't cause >> any issues, we plan to ship it to beta and release at a later date.* >> >> Please let me know if you have any concerns. Many thanks to Nick >> Alexander who supported this effort with a lot of reviews and improvements >> to backgroundtasks. >> >> Thanks, >> Valentin >> >> -- >> You received this message because you are subscribed to the Google Groups >> "[email protected]" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to [email protected]. >> To view this discussion on the web visit >> https://groups.google.com/a/mozilla.org/d/msgid/dev-platform/CACQYfiKjNJVMMkPZy%2BF9AXiO1fJ4ieLhRYgwrkwwPRAe3STDWQ%40mail.gmail.com >> <https://groups.google.com/a/mozilla.org/d/msgid/dev-platform/CACQYfiKjNJVMMkPZy%2BF9AXiO1fJ4ieLhRYgwrkwwPRAe3STDWQ%40mail.gmail.com?utm_medium=email&utm_source=footer> >> . >> > -- You received this message because you are subscribed to the Google Groups "[email protected]" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/a/mozilla.org/d/msgid/dev-platform/CACQYfiLxz5504%2BiLAHNnz-jv%3DqFb8fZp2KOuKySSMphxEswvnA%40mail.gmail.com.
