Open Bug 1602994 Opened 2 months ago Updated 2 months ago

Pressing "Clear Cookies and Site Data" button has a long delay before popup appears, if local storage used


(Toolkit :: Data Sanitization, defect, P2)

71 Branch




(Reporter: jimbo1qaz, Unassigned)


User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:71.0) Gecko/20100101 Firefox/71.0

Steps to reproduce:

  • Use a browser profile with lots of data stored in local storage.
  • Visit any page with cookies.
  • Press the URL bar lock to open the "Site Information" panel.
  • Click "Clear Cookies and Site Data".

Actual results:

The panel remains open and nothing appears to happen for a few seconds, before the panel closes and the "Removing Cookies and Site Data" dialog appears.

If I click the button multiple times, a few seconds later, multiple dialog appear simultaneously.

If I close the dialog and press the button again (on the same tab with the same site open), I get a delay again.

(The delay was 2-4 seconds when I commented on #1468355. Now it's 1 second on, but 2-3 seconds on

Expected results:

The "Removing Cookies and Site Data" dialog appears immediately. Or if there's a long delay, at least there's a visual indication (like a spinner) that something's happening.

This is a follow-up to Earlier, the button didn't appear for 1 or more seconds. That bug has been fixed.

This new issue does not appear on a clean user profile, but appears on my main profile.

Clearing my main profile's extension list and about:config did not help. Moving my profile's storage folder out of my main profile folder fixed the delay.

I have Worldbrain's Memex (, which created a single sqlite DB taking up 750MB in the storage folder. Copying around half of my storage\default folder (100-ish megabytes, not including the 750MB file) to a clean profile was sufficient to reproduce this bug on my clean profile.

When on my clean profile with my main profile's storage\default, visiting, and trying to press "Clear Cookies and Site Data", I received a long delay, and the dialog contained a long list of Google-related domains which would be cleared.

On my clean profile, clearing all cookies using "Clear Recent/All History" (Ctrl Shift Del, "Everything") did not fix the delay, and I still received a long list of domains. Clearing all "Offline Website Data" fixed the delay, and all domains but "" disappeared.

I think the severity of this bug is related to how many domains show up on the dialog box. When clearing on my clean profile, I get 8-ish domains and a 1-second delay. On my main profile, I get 16-ish domains and a 2-second delay.

I am on Windows 10 1909, on a NTFS SSD partition. Merely iterating over all files in storage\default (using fd > nul) takes half a second. Using Windows Explorer to recursively clear the read-only flag of storage takes minutes.

Component: Untriaged → Data Sanitization
Ever confirmed: true
Priority: -- → P2
Product: Firefox → Toolkit
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