3 ms·

Suppose we all live under socialism and capitalist rules no longer apply. Only physics. You run a vacation home exchange/booking site, which you run in 3 insta

by mordae 2y ago

Suppose we all live under socialism and capitalist rules no longer apply. Only physics. You run a vacation home exchange/booking site, which you run in 3 instances in America, Europe and Asia because base you found that people are happier when the site is snappy without those pesky 50ms delays. Now suppose it's the middle of the night in one of those 3 regions, so no big deal, but the rollout of new version brings down the database that's holding the bookings for two hours before it's fixed. Yeah, it was just the simplest solution to have just a one database with the bookings, because you wouldn't have to worry about all that pesky CAP stuff. But people then start to ask if it would be possible to book from regions that are not experiencing the outage while double-bookings would still not happen. So you give it a consideration and then you figure out a brilliant, easy solution. You just

ndriscoll 2y ago
Incidentally, I'm highly suspicious of the claim that those pesky 50ms delays matter much. Checking DOMContentLoaded timings on a couple sites: Reddit: 1.31 s Amazon: 1.51 s Google: 577 ms CNN: 671 ms Facebook: 857 ms Logging into Facebook: 8.37 s As long as you have TLS termination close to the end user, and your proxy maintains connections to the backend so that extra round-trips aren't needed, the amount of time large popular sites take to load suggests that people wildly overstate how much anyone cares about a fraction of a blink of an eye. A lot of these sites have a ~20 ms time to connect for me. If it were so important, I'd expect to see page loads on popular sites take <100 ms (a lot of that being TCP+TLS handshake), not 800 ms or 8 seconds.
- hot_gril 2y ago
  and travel sites will be a lot slower for other reasons
- doctorpangloss 2y ago
  It’s hard to say. It’s common sense that it doesn’t matter that much for rational outcomes. Maybe it matters a lot if you are selling something psychological - like in a sense, before Amazon, people with shopping addiction were poorly served, and maybe 50ms matters to them. You can produce a document that says these load times matter - Google famously observed that SERP load times have a huge impact on a thing they were measuring. You will never convince those analytics people that the pesky 50ms doesn’t matter, because they operate at a scale where they could probably observe a way that it does. The database people are usually sincere. But are the retail people? If you work for AWS, you’re working for a retailer. Like so what if saving 50ms makes more money off shopping addicts? The AWS people will never litigate this. But hey, they don’t want their kids using Juul right? They don’t want their kids buying Robux. Part of the mythology I hate about these AWS and Stripe posts is, “The only valid real world application of my abstract math is the real world application that pays my salary.” “The only application that we should have a strictly technical conversation about is my application.” Nobody would care about CAP at Amazon if it didn’t extract more money from shopping addicts! AWS doesn’t exist without shopping addicts!
  - ndriscoll 2y ago
    What I mean is that Amazon seems to think it doesn't matter that much if they're taking hundreds of ms (or over 1 s) to show me a basic page. The TCP+TLS handshake takes like 60 ms, plus another RTT for the request is 80 ms total. If it takes 10 ms to generate the page (in fact it seems to take over 100), that should still be under 100 ms total on a fresh connection. But instead they send me off to fetch scripts from multiple other subdomains (more TCP+TLS handshakes). That alone completely ruins that 50 ms savings. So the observation is that apparently Amazon does not think 50 ms is very important. If they did, their page could be loading about 5-10x faster. Likewise with e.g. reddit; I don't know if that site has ever managed to load a page in under 1 s. New reddit is even worse. At one point new reddit was so slow that I could tap the URL bar on my phone, scroll to the left, and change www to old in less time than it took for the page to load. In that context, I find people talking about globally distributed systems/"data at the edge" to save 50 ms to be rather comical.

by mordae 2y ago

ndriscoll 2y ago

Incidentally, I'm highly suspicious of the claim that those pesky 50ms delays matter much. Checking DOMContentLoaded timings on a couple sites: Reddit: 1.31 s Amazon: 1.51 s Google: 577 ms CNN: 671 ms Facebook: 857 ms Logging into Facebook: 8.37 s As long as you have TLS termination close to the end user, and your proxy maintains connections to the backend so that extra round-trips aren't needed, the amount of time large popular sites take to load suggests that people wildly overstate how much anyone cares about a fraction of a blink of an eye. A lot of these sites have a ~20 ms time to connect for me. If it were so important, I'd expect to see page loads on popular sites take <100 ms (a lot of that being TCP+TLS handshake), not 800 ms or 8 seconds.

hot_gril 2y ago
and travel sites will be a lot slower for other reasons
doctorpangloss 2y ago
It’s hard to say. It’s common sense that it doesn’t matter that much for rational outcomes. Maybe it matters a lot if you are selling something psychological - like in a sense, before Amazon, people with shopping addiction were poorly served, and maybe 50ms matters to them. You can produce a document that says these load times matter - Google famously observed that SERP load times have a huge impact on a thing they were measuring. You will never convince those analytics people that the pesky 50ms doesn’t matter, because they operate at a scale where they could probably observe a way that it does. The database people are usually sincere. But are the retail people? If you work for AWS, you’re working for a retailer. Like so what if saving 50ms makes more money off shopping addicts? The AWS people will never litigate this. But hey, they don’t want their kids using Juul right? They don’t want their kids buying Robux. Part of the mythology I hate about these AWS and Stripe posts is, “The only valid real world application of my abstract math is the real world application that pays my salary.” “The only application that we should have a strictly technical conversation about is my application.” Nobody would care about CAP at Amazon if it didn’t extract more money from shopping addicts! AWS doesn’t exist without shopping addicts!
- ndriscoll 2y ago
  What I mean is that Amazon seems to think it doesn't matter that much if they're taking hundreds of ms (or over 1 s) to show me a basic page. The TCP+TLS handshake takes like 60 ms, plus another RTT for the request is 80 ms total. If it takes 10 ms to generate the page (in fact it seems to take over 100), that should still be under 100 ms total on a fresh connection. But instead they send me off to fetch scripts from multiple other subdomains (more TCP+TLS handshakes). That alone completely ruins that 50 ms savings. So the observation is that apparently Amazon does not think 50 ms is very important. If they did, their page could be loading about 5-10x faster. Likewise with e.g. reddit; I don't know if that site has ever managed to load a page in under 1 s. New reddit is even worse. At one point new reddit was so slow that I could tap the URL bar on my phone, scroll to the left, and change www to old in less time than it took for the page to load. In that context, I find people talking about globally distributed systems/"data at the edge" to save 50 ms to be rather comical.