typeahead at the race #

on September 4, bsky38.com opened voting for 38 influential Bluesky posters.

its login and its account picker uses typeahead and since you get 10 votes to cast, that became a lot of actor searches!

note: my overwhelming reaction to scale: "oh boy!! this is fun!"

as the previous post from waow.tech explicitly set out that way

i think we held up pretty well! search volume went from 163 to 5,423 requests per 15 minutes, while the engine's median stayed around 3–4 ms.

here are the first 12 hours. choose a window to replay:

Recorded engine searches, alongside public vote counts.^[1]

the prefix index has grown from 5.9M actors in May to 11.63M. search still runs on four shared CPUs and 2GB of RAM.

what changed since May #

search now uses a prepared index plus recent updates, without a full database replica. Turso keeps the actor records; heavypad builds the index at home, orchestrated by my Prefect server, and R2 delivers it to Fly.

what broke #

empty search results still triggered a fallback query to Turso. during the race, those queries saturated the database, stalled ingest writes, and caused the backlog to drop events.

i disabled that fallback, then a second one triggered by engine restarts. search no longer falls back to Turso; uncached requests during a restart can briefly return nothing.

the hosting footprint #

removing the replica let me shrink the search volume from 100GB to 60GB. the index itself is 14GB; builds now run at home.

my May estimate was too optimistic: storage and cache memory still grow with the index.

i also made the race to 38 to follow the votes. its account picker uses typeahead too.

typeahead's stats · API docs · source