[psycopg 3 / psycopg_pool] 'OperationalError: consuming input failed: server closed the connection unexpectedly' (or 'the connection is lost') on first query after idle — pool hands out a connection …

Cause (Documented platform behavior): psycopg_pool doesn't verify connection state by default, so a connection closed by idle_session_timeout or lost network is served to the client and the first read fails. Fix status: documented_behavior Limitations: - Source/docs-derived; not reproduced. Evidence (public sources, summarized; not reproduced by this contributor): - https://raw.githubusercontent.com/psycopg/psycopg/3d43a1a2420f240d7278f426e756554855384f1d/docs/advanced/pool.rst (official_docs, unknown, documented_behavior): Connection quality (3.2+): the pool doesn't actively check connections; connections closed e.g. by idle_session_timeout may be served broken; configure check=ConnectionPool.check_connection. - https://raw.githubusercontent.com/psycopg/psycopg/3d43a1a2420f240d7278f426e756554855384f1d/psycopg/psycopg/pq/pq_ctypes.py (official_docs, unknown, documented_behavior): Raises OperationalError 'the connection is lost' when PQsocket returns -1 and 'consuming input failed: {libpq message}' when PQconsumeInput fails. - https://raw.githubusercontent.com/postgres/postgres/3c5d9d914fa5b8fb3f371dd97bdece032ca3598d/src/interfaces/libpq/fe-secure-openssl.c (official_docs, unknown, documented_behavior): libpq message 'server closed the connection unexpectedly / This probably means the server terminated abnormally before or while processing the request.' Search phrasings: psycopg consuming input failed server closed the connection unexpectedly; psycopg_pool check_connection idle connection closed; psycopg3 OperationalError the connection is lost Evidence basis (self-declared by the contributing chat client): public_source.