The single serial DeliveryWorker is replaced by Infrastructure/Jobs:
- Job rows are leased with one FindOneAndUpdate (oldest RunAt first, a
two-minute lease) and a reaper returns expired leases every 30 s;
- enqueueing wakes the workers, which otherwise poll every five seconds;
- delivery runs eight at a time with at most two per host, so a slow or
dead server holds two slots, not the queue;
- a failure waits n^4 + 15 + jitter seconds (Mastodon's curve) for up to
16 attempts; a 4xx other than 408/429 is final, a 429 honours
Retry-After;
- RemoteInstance is a per-host circuit breaker: ten consecutive failures
quarantine a host for an hour, doubling to a week, and its jobs wait
without spending attempts;
- a delivery is queued once per activity and inbox (unique DedupeKey), and
finished jobs expire after seven days (TTL on FinishedAt).
Migration _004 moves pending Delivery rows into jobs and marks them
abandoned, so a rollback to the old worker cannot send them twice.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_012CzABvBkbcFqoHdmi8b9WB
Infrastructure/Data/Indexes runs at every start, after the migrations:
unique on Post/DmPost ObjectURI, ForeignAvatar ActorURI, the Follower
triple, RootToAvatar, RootUser UserName and ReservedName; plain indexes on
the lookups the services actually make (PublicKeyId, author and group
post listings, ParticipantsKey, the delivery queue).
Migration _001 runs first and removes the duplicates the races could
already have left (keeping the newest actor row, the oldest post, the
accepted follower), then fills ReservedName from every avatar and group.
ReservedName is one username space for personas, groups and the instance:
a name is reserved by an insert the unique index arbitrates, before the
avatar or group is saved, so two simultaneous sign-ups cannot both get it.
A short list of names (admin, support, abuse, postmaster, ...) is never
available.
EntityMaps.Warm touches every entity's collection one at a time before
anything else runs. MongoDB.Entities maps the Entity base class on first
touch, and two types mapped at once throw "An item with the same key has
already been added" and stay broken for the life of the process; the
parallel test run hit it, and the delivery worker racing a request could
have too.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_012CzABvBkbcFqoHdmi8b9WB
thepraandClaude Opus 5.5