* feat: defer embedding messages
* fix: rm gauges
* feat: embed messages immediately on create with reconciler fallback (#766)
Adds embed_messages_now background task so newly created messages are
searchable within seconds instead of waiting up to the reconciler
interval. Three-phase claim/lease → embed → persist never holds a DB
session across the embedding call; the reconciler remains the fallback
for failures and stragglers.
* fix: harden immediate-embed fast path and cover its error branches
Wrap embed_messages_now in a top-level try/except so a failure in the
claim or persist phase degrades to "reconciler will retry" instead of
escaping into the background-task runner; the rows stay pending+leased
and the reconciler heals them.
Add tests for the previously-uncovered branches: external-store-unavailable
persist path, the file-upload endpoint's embed scheduling, and direct unit
tests for the shared compute_chunk_positions / build_message_vector_record
helpers.
Document the semantic-search eventual-consistency window in search.mdx
(keyword matches are immediate; vector matches lag creation by seconds).
* fix: don't hold DB session across vector-store upserts
* fix: align semantic-search function to filter null rows
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Co-authored-by: Vineeth Voruganti <13438633+VVoruganti@users.noreply.github.com>
Eugene Eisenstein
Rajat Ahuja