Comment by CobrastanJorji | Hacker News Reader

Comment by CobrastanJorji | Hacker News Reader

It takes hours, therefore it must not be a computer? I know the author has industry experience with ML and scientific computing, so this conclusion is surprising to me. Big data pipelines, especially those that involve a lot of money, especially especially the ones that are messy and potentially unreliable and have large ups and downs in demand, are not necessarily fast. Maybe there was a bunch of sales and there's a queue. Maybe there's a buffer where they check every few hours to see if inventory matches sales. Maybe they manually validate a couple of orders in each batch before releasing the automated results. Maybe the fleet doesn't autoscale and it's overprovisioned at night but underprovisioned when you're actually shopping. Maybe it sometimes handles the work in large batches, and maybe that job periodically fails due to regular bugs and has to be restarted.

There are lots of "this works but not instantly and not 100% reliably" answers. "It was a mechanical turk all along" is not the only logical conclusion from the presented evidence.

And "usually takes a couple of hours"...isn't very bad? Is it ideal? No. Is it enough to ask "How Has Amazon Come To This?" Also no.

This would be a good excuse for a smaller company that doesn't have the resources but amazon is literally the largest cloud provider in the world. Amazon could scale instantly to deal with queue size no problem and at cost since they own the aws services needed to do so. I don't think queue size or under-provisioning makes sense here at all. Validation and some human element checking inventory matches sales makes sense but that's essentially what the author is suggesting is going on here.

Does Amazon Fresh lose revenue by sending receipts slowly? On demand compute is likely more valuable to sell.

Prompt receipt of a receipt is valuable to the customer. It enables them to promptly dispute mistakes, submit expense reports, allows for return of purchases (valuable also to Amazon: imagine the enormous headaches adapting a system to allow for the return of an item your system doesn't currently believe someone bought yet), etc.

Amazon sends the receipt the moment they charge you. Amazon Go does not do "returns". You just click "request a refund" and they give you your money back. This is more convenient than other stores.

It must cost them some revenue because quick receipts is a much better user experience. The receipt system will inevitably make mistakes and it's much easier for the customer to deal with those before leaving the area and getting involved in something totally different.

I see little correlation between such minor user experience quibbles and sales in US retail.

You can't even tap a MasterCard to pay in any of the top 3 brick and mortar retailers in the US. Nobody is going to walk 2 more blocks past an Amazon Go/Fresh because they want their receipt faster. Or at least, the demographic who would is likely not the demographic Amazon is targeting. These stores are going up in neighborhoods where people are relatively unlikely to look at their receipts anyway.

There’s no way I would have Amazon automatically bill me 2 days after I left the store

Why? A lot of bills I get a month after the fact.

Because if they made a mistake what evidence would I have to prove otherwise? Sounds like a nightmare waiting to happen, especially given how arcane AWS billing and Amazon account management is in general. What if they billed you for $1,000 worth of groceries?

They don’t ask you to prove anything. You click the refund button, and you get your money back.

> checking inventory matches sales

That's my guess. They wait until the end of the day and see what they have in the store, since that's got to be the easiest of all of this to automate with cameras.

Then they see how far off the AI was for the day and work on error correction and send receipts.

I agree with your overall point that cloud resources probably shouldn’t be a problem for Amazon that factors into the hours of processing time. But is it true that AWS could provide at-cost resources to sister companies?

More of a legal/organizational question. But assuming Amazon Fresh is a legally-distinct entity with service agreements with Amazon Web Services, wouldn’t offering those services at below-market-rate be considered anticompetitive (and also call into question the legal separation of the two entities)?

My understanding internally at amazon is they have the same cloud tools that smaller companies have with AWS. I seriously doubt amazon is keeping some secret AWS sauce for internal-use-only.

They do, source: I worked at Amazon.

The simplest explanation, IMO, is to look at the piece Amazon doesn't own. The bandwidth to send a continuous stream of 4K video from dozens (hundreds?) of cameras from the store to the cloud for processing. That can't be cheap.

Netflix 4K seems to be about 7GB per hour. A camera aimed at a store should be able to get away with much less, since the image is mostly static. But let’s say 7GB per hour.

If all the processing were in the cloud and the data were going in the other direction, AWS might charge 5c / GB, so 35 cents / hour. Peanuts.

But AWS owns the infrastructure, and they don’t charge for ingress anyway. A 1Gbps link might cost $2k per month (wild guess, but not far enough off to matter). That covers 64 streams. This cost is minimal.

Of course, AWS could also stick enough of their processing at the edge to essentially eliminate the bandwidth cost entirely.

My (admittedly residential) symmetric gigabit internet costs... $700/year.

My guess is that it isn't fast because there's no reason for it to be fast. There is no reason for that to be a design requirement.

You've never checked a receipt on your way out of the store to make sure you weren't charged for anything you didn't purchase?

I check the receipt when I'm charged. Same as with Amazon Fresh.

Every time my groceries arrive I'm somewhat clueless as to what I ordered, though past me always seems to have made good choices. Checking my recipt after 50 hours would effectively be useless.

I suspect 50 hours is an extreme. Last time it took me 2 hours to get my receipt.

With the invention of self checkout I never get charged for an item I didn’t purchase. I have never encountered that issue with a cashier either.

Hell I cannot remember a time when I was _charged for something I didn’t purchase_.

I have been charged MORE than advertised but paying attention while ringing up the item and escalating to the cashier or manager typically solves the problem. I have also been charged less and notified the cashier of the issue.

Why would you check your receipt _after_ you left the store? Now you have to drive back, go inside, go to customer service and wait.

Seems way easier to pay attention and scan the receipt when it is handed to you.

In what world is "knowing how much you spent" not a reasonable design requirement for a supermarket?

Just to pick one user story, it's a lot harder to check / challenge an itemized receipt if you receive it hours later, once you're already packed things away or eaten some of them.

You're looking at it backwards. Why would you ever want customers to see their total spend?

It is reasonable. The price is on the shelf. But if you insist they have this too: https://static2.srcdn.com/wordpress/wp-content/uploads/2020/...

It's easier to challenge an Amazon Go receipt than any other store. I just click the link in the email and get my money. At other stores, I have to go inside and wait in line behind other people at the customer service desk. I prefer to get on with my day rather than argue over the price of a cabbage.

> Maybe the fleet doesn't autoscale and it's overprovisioned at night but underprovisioned when you're actually shopping.

It's further worth remembering that Amazon happens to, y'know, own AWS. Since this is not a time sensitive result at all, they could be trying to do it in spare capacity by specifically downscaling when their customers tend to use things. It's complicated to pass that efficiency on to customers, but it's probably super easy to take advantage internally.

no need to even get into ML.

amazon seller inventory reports may have 2 or 3 days of delay on a bad day.

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