Two uvicorn workers each hold a LISTEN connection on wiki_page_changes, so
Postgres delivers every notification to both and each page edit is ingested
twice. Found while verifying the v1.9.1 reconnect fix — the reconnect logged
twice, which is what gave it away.
Proven with a colon-free pg_notify payload that is rejected before ingestion
runs: one NOTIFY, two "Invalid notification payload" lines. Recorded with the
reproduction rather than the conclusion alone, since whether this corrupts data
or is only wasteful has not been established.
Co-Authored-By: Claude <noreply@anthropic.com>