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What is firefox's cookie limit and how does it handle corrupt cookies store

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  • 1 has this problem
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  • Last reply by cor-el

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I've been digging into an issue about the "A web page is slowing down your browser," and it seems that the most frequent explanation for this is corrupt cookies/cache. However, the issue wasn't repeatable on my site. After some digging, I found that its possible for a corrupt `cookies.sqlite` if the max file size has been reached and a suggestion that FF automatically resets this `cookies.sqlite` store when this happens.

I suspect that this issue happened when the user maxed out their cookies, causing a corrupt `cookies.sqlite` file. Then, when they restarted FF, their store had been cleared and they had no problems.

However, I cannot find any documentation about FF behavior when in handling corrupt cookies or resetting the `cookies.sqlite` file. I'm looking for some concrete answers. What is FF's cookie store limit, and what is its behavior (if any) when the store is maxed?

Worth mentioning, this was FF on Linux. I don't know the specs beyond that.

I've been digging into an issue about the "A web page is slowing down your browser," and it seems that the most frequent explanation for this is corrupt cookies/cache. However, the issue wasn't repeatable on my site. After some digging, I found that its possible for a corrupt `cookies.sqlite` if the max file size has been reached and a suggestion that FF automatically resets this `cookies.sqlite` store when this happens. I suspect that this issue happened when the user maxed out their cookies, causing a corrupt `cookies.sqlite` file. Then, when they restarted FF, their store had been cleared and they had no problems. However, I cannot find any documentation about FF behavior when in handling corrupt cookies or resetting the `cookies.sqlite` file. I'm looking for some concrete answers. What is FF's cookie store limit, and what is its behavior (if any) when the store is maxed? Worth mentioning, this was FF on Linux. I don't know the specs beyond that.

All Replies (3)

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There is no maximum for the number of cookies. There is only a maximum for the size of an individual cookie. I don't think that corrupted cookies would cause a website to run slow, you normally get an error that the request is too large and the server isn't able to handle it.

If cookies are corrupted then you need to clear affected cookies for this domain yourself and if that doesn't work then you will have to remove all cookies.sqlite files with Firefox closed.

See also:

You can check the Firefox Task Manager (about:performance) and about:memory pages.

Modified by cor-el

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Thanks for these links. Unfortunately, they would only be helpful if the problem had happened to me (I'm investigating an incident), though they do seem to indicate what I've suspected all along: its a client-side issue that we can't really control.

However, your mention that corrupt cookies or cache won't cause a slow down is contrary to a response from a year and a half ago: [https://support.mozilla.org/en-US/que.../1241649]. Has something changed?

Lastly, is there any behavior in FF that automatically manages cookies or cache (your previous answer suggests no)?

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^: in that thread to user solved the problem by enabling Tracking Protection to prevent third-party from loading 'ad' content. The advice regarding cookies didn't help and such advice (clearing cache and cookies for affected websites and checking installed extensions) is usually given as a first thing to try in issues with websites to make sure that it isn't caused by corrupted data.