connection_does_not_exist Connection Does Not Exist — SQLSTATE 08003

The application tried to use a connection that is already closed.

• The error is written to the server log and returned to the client carrying SQLSTATE 08003.
• Any driver (libpq, JDBC, psycopg, npgsql, pgx) surfaces this code in its error object so you can branch on it programmatically.
• PL/pgSQL can trap it by name: EXCEPTION WHEN connection_does_not_exist THEN.

Severity: ERROR  |  PostgreSQL versions: 12, 13, 14, 15, 16, 17

Commonly coincides with restarts, failover, maintenance, or network events; check server uptime and the log around the timestamp.

The client issued a command on a connection object whose server-side backend no longer exists.

Common causes:

• A pooler recycled or closed the backend.
• The session timed out (idle_session_timeout).
• A prior fatal error closed the connection.
• The application cached a connection past its lifetime.

Steps to resolve 08003:

1. Detect closed connections and reconnect before issuing queries.
2. Validate connections on checkout from the pool (health-check query).
3. Align client, pooler, and server idle timeouts so none closes a connection the others still hold.
4. Do not cache long-lived connections across requests without a liveness check.

Reference: PostgreSQL error codes — Class 08 (Connection Exception).