Thread by @gravislizard

i think most people do not realize the extent to which computer operations are either a) not logged b) logged in a format that is difficult for even an expert to make definitive statements about c) not realistically loggable

so, there's only really two ways to log changes to a dataset
a) snapshots - every time something changes, you save the entire thing. never done. astronomically resource-expensive.
b) deltas - very small. useless unless you have frequent snapshots and a tool for "playback"

the latter can also be thought of as "console.print" I suppose. debug output. a lot of logs are just like "[timestamp] <apicall> <parameters>"

so, you can ask a question like "when was this setting changed to <blah>?" and an answer might be forthcoming. but the question "what was it BEFORE that" is... very possibly unanswerable.

I know in the case of my employer it simply is not answerable in most cases because our primary product runs on a system we don't develop, and it only logs deltas. When someone changes the number their phone is forwarded to, it only logs the NEW number.

if it logged the old value, we could possibly scrub back in the logs, because we'd have a sentinel value. newnumber = x, oldnumber = y - just search the logs for newnumber = y and now you know when it was set to that value, and you have start/end dates.

even with our system only logging deltas, it produces 30 megs of logs *per second*. we have several gigs dedicated to logs, and it only stores like a day of records. I don't really see a way to fix this.

that is to say, while the DEVELOPER could fix it, they don't give a shit about us or our needs, and have survived 20 years without fixing it, which means they feel no incentive to fix it.