

Ask HN: 'Unknown or expired link' - dashausbass

Why does the &#x27;more&#x27; link at the bottom give &#x27;Unknown or expired link&#x27; at certain times?
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ColinWright
This has been discussed many, _many_ times. Try searching for it in the search
box at the bottom of each page.

However, short answer:

The ordering of items on a page can change, so when you open the page the
ordering is created, and continuation pages are generated by closures in the
code. These closures are garbage collected after a while, so if you don't
access one in a timely fashion, by the time you ask for it, it might no longer
be there.

Garbage collections will happen more often when the system is more heavily
loaded, so the time limit is effectively shorter.

Now, here is some background reading:

[https://hn.algolia.com/?q=unknown+expired#!/story/forever/0/...](https://hn.algolia.com/?q=unknown+expired#!/story/forever/0/unknown%20expired)

You could have looked that up for yourself. Did you?

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iamdanfox
The overall ranking is updated every few minutes. Each front-page has a
different `?fnid=xiJqLAhmD8VrsD2p21gUKn` parameter to ensure page 2 displays
that ranking. Clicking the `more` link after HN has updated shows you the
expired link message.

I guess this means they don't have to store all the old rankings, but it does
seem curious not to allow people to view old rankings.

