4 ms·

It's a bold boast, but honestly, it doesn't mean much if the problem domain isn't similar. Reddit in particular runs into issues because so little of what they

by cheald 16y ago

It's a bold boast, but honestly, it doesn't mean much if the problem domain isn't similar. Reddit in particular runs into issues because so little of what they do is widely cachable. The site is heavily customized per user, and experiences an awful lot of cache churn. I don't disagree with your sentiment (design matters more than choice of language), but I could serve 16 million static pageviews/day off of a $20/month Linode. That doesn't mean that reddit could do the same.

teej 16y ago
Reddit has 8 million unique visitors, but only 300k subscribers to /r/pics, the top auto-subscribed subreddit. Generously assuming half of people manually unsubscribe, that's at most 7% of their user base that are logged in. I know full well about cache churn with logged in users, but that's a lot of lurkers. I'm also not sure what makes a Facebook game's domain more "widely cachable". 100% of users are logged in. The vast majority of actions taken are changing state. Any app touchpoint is writing to the database. Page caching is nearly impossible. It's a lot less different than you think.
- cheald 16y ago
  I can't claim to know the specifics of your application, but consider that a single upvote invalidates however many thousand copies of a given page. An action in a Facebook game might invalidate a page for 10 or 20 or 50 users. An upvote, (or a comment, or an edit, or an upvote on a comment) invalidates that page for upwards of 300k+ users. Combine that with the rate at which reddit's pages change, and you're talking an obscene amount of CPU time spent building fragments/pages to stick into your cache. Scope of visibility of a change means a lot. You obviously know how to scale an app if you were pulling 16 million pageviews a day, and I don't intend to discount that at all. I just mean to point out that while fundamentally the same problem, reddit has to deal with a version of that particular problem that most applications don't begin to approach.
  - parfe 16y ago
    >a single upvote invalidates however many thousand copies of a given page I never understood this. Does reddit really need to spend the capital making sure I see a stranger's upvote the moment it occurs? A 60 second delay to refresh pages in batches seems perfectly reasonable. Perhaps with a client side script to mark my own upvotes so the system doesn't look like is losing my selections.

by cheald 16y ago

teej 16y ago

Reddit has 8 million unique visitors, but only 300k subscribers to /r/pics, the top auto-subscribed subreddit. Generously assuming half of people manually unsubscribe, that's at most 7% of their user base that are logged in. I know full well about cache churn with logged in users, but that's a lot of lurkers. I'm also not sure what makes a Facebook game's domain more "widely cachable". 100% of users are logged in. The vast majority of actions taken are changing state. Any app touchpoint is writing to the database. Page caching is nearly impossible. It's a lot less different than you think.

cheald 16y ago
I can't claim to know the specifics of your application, but consider that a single upvote invalidates however many thousand copies of a given page. An action in a Facebook game might invalidate a page for 10 or 20 or 50 users. An upvote, (or a comment, or an edit, or an upvote on a comment) invalidates that page for upwards of 300k+ users. Combine that with the rate at which reddit's pages change, and you're talking an obscene amount of CPU time spent building fragments/pages to stick into your cache. Scope of visibility of a change means a lot. You obviously know how to scale an app if you were pulling 16 million pageviews a day, and I don't intend to discount that at all. I just mean to point out that while fundamentally the same problem, reddit has to deal with a version of that particular problem that most applications don't begin to approach.
- parfe 16y ago
  >a single upvote invalidates however many thousand copies of a given page I never understood this. Does reddit really need to spend the capital making sure I see a stranger's upvote the moment it occurs? A 60 second delay to refresh pages in batches seems perfectly reasonable. Perhaps with a client side script to mark my own upvotes so the system doesn't look like is losing my selections.