Ken and Pat argue (split from The Super-Duper Cheap Bargains Thread)

[Pat B]

Sigh. That means your browser won't cache, right? You realize that caching can occur behind the reverse proxy your https connects to?

Sigh indeed. Why, at this point, would you speculate on what it means? The spec for the no-store directive (RFC2616 14.9.2) specifically states, "This directive applies to both non-shared and shared caches." And I think you already know why it would be a very bad idea for an intermediate cache to ignore this directive.

[Ken B]

You are at a table in a cafe, and I am at another. They sell muffins. You ask your waiter if there are muffins left. He looks, sees three, and says "Yes, three."
While you cogitate I have the same conversation with my waiter.
I order two muffins posthaste. My waiter, close to the muffins, grabs two.
"I will have two" you say and your waiter heads towards the counter ...

Variations are possible. You speak before I do but your waiter is slow and my quick. Or your waiter looks just before mine grabs the muffins.

This might be a rare scenario but it is plainly a possible one. So is the variant with only one muffin left.
Even more possible is online sales of a discounted item where there is suddenly a rush of orders.

What has happened is that your server's data about the number of muffins left is out of date at some point, briefly.

It's worth noting that if there had been 7 muffins left when he told you, "Yes, 7" that would have been just as out of date, since there would have only been 5 available to you,  but it wouldn't have mattered or been noticed.

[mc ukrneal]

I'll take a muffin!! But I won't share my cash. Sorry.

[greg]

There's free muffins? Where?

[Pat B]

Are we still talking about http caching? Because your latest analogy sounds like you've switched the subject to coherency for distributed databases.

[Ghost of Baron Scarpia]

If what's-his-name had just hit refresh this whole pissing match could have been avoided.

[mc ukrneal]

Ooooh FRESH muffins! 

[Ken B]

Are we still talking about http caching? Because your latest analogy sounds like you've switched the subject to coherency for distributed databases.

No switch at all since my post was about how these things can happen in distributed systems like the net. We were never discussing just http caches. I was trying to explain to people who seemed pissed off some of the ways that what happened with their orders might have happened. And you burst in with the, I thought rude, dismissal of an analogy which is not only good but commonplace.

[Pat B]

We were never discussing just http caches.

I thought we were almost entirely talking about http caches.

The exception being your scone analogy, and my one-sentence response to it. I'll admit that it deserved a better response than I gave it.