postgres on krtffl.dev

clean and verified are different claims: a two-axis trust state machine in postgres

Mon, 11 May 2026 00:00:00 +0000

ask a language model for a line of tacitus in spanish and it will hand you a sentence. fluent, confident, correctly punctuated. and sometimes the sentence contains a word that no translator ever wrote — a word a scanner invented, when it read the á in a 1919 printing as the digit 4, or turned violento into violen10, and then a spell-checker came along afterward and smoothed the wreckage into something that looks like spanish.

the text is clean. it is not correct. and nothing about the way it reads tells you which.

i audited my side project like it was about to go viral (before it was)

Mon, 29 Dec 2025 00:00:00 +0000

i ended the last post with a promise: a public stats page that ran three full-table scans on every request and fell over the first time i pointed real concurrency at it. this is that post — the last of three findings from the same pre-launch audit of a little pairwise-voting side project, a nougat-ranking toy where you pick between two flavours and a leaderboard falls out.

the first two findings were bugs: an elo race that ate 79% of every vote , and a rate limiter a rotated header walked straight through . this one is a bug too, but it’s really about the method that surfaced it, because the method is the transferable part. the bug — a page doing linear work per request against a table that only grows — is one you’ve almost certainly got somewhere right now and can’t see, for the exact reason i couldn’t: on your dev box the table has forty rows and everything’s instant. the page isn’t slow. the page is a landmine with the pin still in, and the only way to find it before your users do is to go step on it yourself.

so that’s the method. stand up a throwaway postgres, seed it with the amount of data you’d have if the thing actually worked — if it went viral, if the launch landed — and then measure the hot paths under that load instead of guessing. the very first page i pointed it at turned out to be a denial-of-service i was hosting for free, on purpose, with a smile.

the elo race that silently ate 79% of every vote

Mon, 15 Dec 2025 00:00:00 +0000

it’s the kind of bug that lets you sleep fine for weeks.

i’d built a little nougat-ranking toy — you get shown two flavours, you pick the one you’d rather eat, and an ELO rating quietly updates in the background so a leaderboard falls out of thousands of these pairwise duels. side project, single box, htmx and go and postgres, held together with database/sql and good intentions. it worked. people voted. the leaderboard moved. every vote came back with a fresh pairing and a 200. green across the board.

then, before pushing it anywhere with real traffic, i did a proper hardening pass: stand up a throwaway postgres, seed it with a plausible went-viral amount of data, and hammer every endpoint like someone who wants to break it. the very first thing i measured told me that roughly four out of every five votes had been quietly doing almost nothing the whole time.

not erroring. not failing. the vote was recorded. the rating just didn’t move the way it was supposed to.

sqlc + pgx over an orm: type-safe sql that fails at compile time

Mon, 24 Nov 2025 00:00:00 +0000

the endpoint was slow and i couldn’t tell you which query to blame, because i hadn’t written any. that’s the deal you sign with a reflection-based orm: you describe some structs, you call db.Preload("Photos").Find(&pets), and somewhere behind the curtain the library assembles sql you never see, fires off a number of round trips you never counted, and hands you back objects. when it’s fast, it’s lovely. when it’s slow, you’re debugging a library’s imagination.