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McDonalds Event Driven Architecture

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Re: McDonalds Event Driven Architecture

#61

Post by andy800 »

BoorishBears wrote: post #51
guyzero wrote: post #44

Serious question, isn't think just rebuilding the same thing that commercial cloud pubsub offerings already provide?

I mean I'd expect if they're already all-in on AWS they'd just use Firehose with some deduplication instead of whatever home-brew fallback solution they described, but other than that it doesn't seem like they built much? What's impressive to me is that they need all that architecture. Mcdonalds sells under 100 burgers a second from what I can find, their order load is probably bursty, so assume maybe all the orders…

I'd guess that 100x database interactions per order may be more like it. Upon startup, there's a whole login, check app version, payment cards still valid, geo query sequence. Check user's point total, rewards, custom offers. Load menu based on chosen store availability and prices. Every menu item has multiple options (mcnugget sauce, burgers without tomato, type of soda). Add to cart. Remove from cart. Add something different to cart. Repeat. Ok, order ready? Check taxes in local jurisdiction. Adjust total based on offers/rewards. Delivery or pickup? Pickup in-store, curbside, drive-thru? Communicate order to store. Update order status based on customer arrival. Send code to customer. Update status upon pickup/delivery. Lots more in-between I skipped, and that's just user-facing, nothing about analytics, accounting, loyalty club, etc.

I'm not defending McDonald's or it's architecture -- as I stated elsewhere, the app is far from perfect, and an entirely different architecture could very easily work much better. But I do think you are severely downplaying the number of interactions or transactions required to run an app like theirs.

Re: McDonalds Event Driven Architecture

#63

Post by BoorishBears »

andy800 wrote: post #61
BoorishBears wrote: post #51

Earlier quoted context omitted.

I mean I'd expect if they're already all-in on AWS they'd just use Firehose with some deduplication instead of whatever home-brew fallback solution they described, but other than that it doesn't seem like they built much? What's impressive to me is that they need all that architecture. Mcdonalds sells under 100 burgers a second from what I can find, their order load is probably bursty, so assume maybe all the orders…

I'd guess that 100x database interactions per order may be more like it. Upon startup, there's a whole login, check app version, payment cards still valid, geo query sequence. Check user's point total, rewards, custom offers. Load menu based on chosen store availability and prices. Every menu item has multiple options (mcnugget sauce, burgers without tomato, type of soda). Add to cart. Remove from cart. Add something…

I mean you wrote all this justification, but 30k per second is still practically nothing compared to the complexity described in the article?

Taking something like Postgres and sprinkling in some strategic use of Redis would handle their usecase with horizontal scaling pretty reliably...

What it wouldn't do is let you add Kafka to your resume.

Re: McDonalds Event Driven Architecture

#64

Post by BoorishBears »

ehnto wrote: post #55
BoorishBears wrote: post #51

Earlier quoted context omitted.

I mean I'd expect if they're already all-in on AWS they'd just use Firehose with some deduplication instead of whatever home-brew fallback solution they described, but other than that it doesn't seem like they built much? What's impressive to me is that they need all that architecture. Mcdonalds sells under 100 burgers a second from what I can find, their order load is probably bursty, so assume maybe all the orders…

I think you are underestimating how liberal some applications are, especially as analytics is one of their requirments. It's probably multiple events per thing you do. I wouldn't be surprised by 100+ events before even placing an order.

Forest for the trees, I already practically doubled my numbers and assumed McDonalds gets all their orders in the same 8 hour period! And even then multiplying them by 100 doesn't get you into the realm of "we couldn't build this on a monolithic horizontally scaling application".

If anything, if you're at McDonalds scale and still can't find the engineering skill to build a monolith that can handle 30k operations per second, you're playing with fire building a distributed system.

(if you're a nascent startup, then by all means stand on the shoulder of giants and don't sweat that you don't have a full blown cloud engineering org, but that's definitely not where McDonalds should be...)

Re: McDonalds Event Driven Architecture

#65

Post by ehnto »

BoorishBears wrote: post #64
ehnto wrote: post #55

Earlier quoted context omitted.

I think you are underestimating how liberal some applications are, especially as analytics is one of their requirments. It's probably multiple events per thing you do. I wouldn't be surprised by 100+ events before even placing an order.

Forest for the trees, I already practically doubled my numbers and assumed McDonalds gets all their orders in the same 8 hour period! And even then multiplying them by 100 doesn't get you into the realm of "we couldn't build this on a monolithic horizontally scaling application". If anything, if you're at McDonalds scale and still can't find the engineering skill to build a monolith that can handle 30k operations per…

Architecture reflects organization structure more often than not. What I see is not an attempt to handle requests rates, but an attempt to service a widely distributed set of applications and handle the inevitable churn of client applications requirements.

I am on team monolith, but I also don't see any issue with this approach if you are happy accepting it's caveats and vendor lock in, which they it seems they were.

Re: McDonalds Event Driven Architecture

#66

Post by tstrimple »

andy800 wrote: post #60

I am, for better or worse, a "heavy user" of the McDonald's app. And unfortunately, all this architecture somehow still misses so many usability issues. The most annoying one, is that the app always defaults to the closest location "as the bird flies." Despite the fact that I have "favorited" a different store, and also my last 5 or 10 orders were placed at this favorite store, the app ALWAYS defaults to the first st…

The one and only time I've used the app was when I thought it would help them during the pandemic when drive thru's were actually slammed with demand while they didn't have enough workers. After waiting in the parking lot for 30 minutes while literally dozens of cars went through the drive through I went in to check on the order and the employees literally couldn't look up the status of my order without an order number which the app didn't give me at the time. An incredibly frustrating experience which turned me off to the concept altogether.

Re: McDonalds Event Driven Architecture

#68

Post by wincy »

andy800 wrote: post #60

I am, for better or worse, a "heavy user" of the McDonald's app. And unfortunately, all this architecture somehow still misses so many usability issues. The most annoying one, is that the app always defaults to the closest location "as the bird flies." Despite the fact that I have "favorited" a different store, and also my last 5 or 10 orders were placed at this favorite store, the app ALWAYS defaults to the first st…

I also use it a lot (I have a disabled kid who went from feeding tube to chicken nuggets and LOST weight, whatever she wants she gets).

After you order and drive away, I’ll find the app hours later still tracking me and using GPS. I almost always have to force close the app.

Then the next time I use it the previous order won’t have cleared out despite me picking it up, and I’ll have to go in and “cancel” the order.

The coupons are good though. For a week or two it was giving 30% off, and almost always has a 20% off coupon.

Re: McDonalds Event Driven Architecture

#69

Post by andy800 »

BoorishBears wrote: post #63
andy800 wrote: post #61

Earlier quoted context omitted.

I'd guess that 100x database interactions per order may be more like it. Upon startup, there's a whole login, check app version, payment cards still valid, geo query sequence. Check user's point total, rewards, custom offers. Load menu based on chosen store availability and prices. Every menu item has multiple options (mcnugget sauce, burgers without tomato, type of soda). Add to cart. Remove from cart. Add something…

I mean you wrote all this justification, but 30k per second is still practically nothing compared to the complexity described in the article? Taking something like Postgres and sprinkling in some strategic use of Redis would handle their usecase with horizontal scaling pretty reliably... What it wouldn't do is let you add Kafka to your resume.

To be clear, I was not justifying the current architecture, I specifically wrote "an entirely different architecture could very easily work much better."

I was pointing out, however, that, as is often the case, the initial estimates in a typical "why do they need all this stuff" post, likely underestimated the transaction volume by possibly 10x. Perhaps 3000 or 30000 transactions per second could run on the same system -- I'm not an expert at that scale. But I doubt you'd find any Fortune 100 company relying solely on Postgres and Redis.

Re: McDonalds Event Driven Architecture

#70

Post by bee_rider »

achrono wrote: post #2

While this satisfies some idle curiosity, I don't really get what justifies spending the resources in posting such stuff. Is this a recruitment tactic somehow for such companies?

Probably, yeah.

But I’m always shocked for some inexplicable reason to hear that places like McDonalds and Walmart Labs are interested in solving tech problems. But I mean obviously, of course they are.

Good to be reminded now and then that there are alternatives to contributing to the ad/social media panopticon, right?

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