111–120 of 142 posts
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Mandela effect
It's the result of people repeating what they read on the Internet, not what they personally experienced. This happens way too often
You're not wrong; but fyi it only happens in your originating universe. Over here we all experienced it.
I'm just curious, I know it's a long running joke about how we're so stupid to think that we would never run out of unique digits with 2^32 possible values, but is this also the case with 64 bit values? Every new bit doubles the amount of information, so if 32 bits lasted reddit 10 years, presumably 33 bits would last them 20 years, 34 would last 40 and so on. Eventually, 64 bits would last them 10×2^32 years, which…
I think it is a horrible assumption to think that Reddit won't grow and will take exactly the same length of time to double the number of unique ids required. But still 64 bits should be plenty for a while. And presumably if it comes closer to using that many they'll have enough time to switch to 128
It appears that the original developer thought that for 32 bits :)
I say that as someone who inherited a system that allowed for 2^32 session references stored in the db. Lets just say that sessions were created a lot faster than anticipated for the amount of traffic we had.
So one fine Sunday morning in a November a long time ago we ran out.
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That doesn't change anything... it's still round robin. You just stopped at an arbitrary number of 8 integers instead of 9.
It's not arbitrary, GP stated it was a 3 bit counter. In GGP (or something, not sure how far down in the thread we are), they were referring to a 32 bit int counter until overflow. If you bin each number from 0 to 2^32 - 1 by mod 3, you don't get 3 bins of equal sizes, 1 bin always comes out smaller.
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Not when the counter overflows back to 0. If it's a 3 bit counter, 0 is A again, not C.
The comment says a 32-bit signed int. Where is the 3-bit assumption coming from?
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The comment says a 32-bit signed int. Where is the 3-bit assumption coming from?
The comment starts with that assumption for the sake of a concise example. do you expect them to write the whole sequence out using a 32bit counter? :-D
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The comment says a 32-bit signed int. Where is the 3-bit assumption coming from?
The comment starts with that assumption for the sake of a concise example. do you expect them to write the whole sequence out using a 32bit counter? :-D
A long time ago we discovered Twitter used a round robin of three servers for assigning IDs to tweets. We inferred the round robin was done by doing mod 3 of a signed int32, and because that space doesn't divide neatly by two it meant one of the three servers saw less load than the others and we could map ID assignment volume according to how often it overflowed and hence estimate total tweet volume for a given perio…
I am pretty sure that snowflake didn't use a mod of a signed int32. It used a service discovery pool as part of finagle (and prior to that dns iirc). The server used a very simple method internally to convert time into a integer (that was 52 bits because of javascript). In fact it was completely open source: https://blog.twitter.com/engineering/en_us/a/2010/announcing... The integer generation was pretty simple, ther…
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The comment starts with that assumption for the sake of a concise example. do you expect them to write the whole sequence out using a 32bit counter? :-D
Then it's irrelevant. The point is that the remainders are evenly distributed as the integer is incremented, with at most a single round being short. That's just how the math works.
Edit to add: whether that's a big enough effect for the use case they're talking about, I don't know. This sort of thing is definitely significant in cryptographic code, though.
If I'm understanding the shitty change log exactly, was the solution to add an extra bit?
Well, I say that, but actually, "adding an extra bit" is basically what going from signed to unsigned would do. So maybe they just added an extra (32nd) bit?
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Strange thing is that photo albums re relatively new. Imgur was the go-to host for Reddit, and then they made their own uploader a looong time later. The "albums" functionality only came out in July of 2020, according to a Google search. Seems this was less likely a "someone else will deal with it" problem, and more of a development / QA testing problem.
For some reason most stuff still defaults to i32 and a lot of people use them for new code. At this point I'd not be against linters warning against using 32 bit ints unless you have a good reason.