The AS page and /api/v1/as/{asn} grouped every route the AS originates
by prefix, reading one table row per peer and prefix and sorting them
all. They now take the AS's prefixes one at a time: one search of a new
index on origin_asn and prefix, which replaces the origin_asn index and
is written exactly when it was, and one search of the prefix and
last_updated index for the time of the prefix's newest route. Neither
reads the table. For a prefix more than one AS originates, that time is
now the newest route's from any origin. A hand-run benchmark reads an
AS of 5,000 prefixes from 500 peers.
Model: opus-5-5
sneak