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.

sql on krtffl.dev

the elo race that silently ate 79% of every vote

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