fdw_unable_to_establish_connection
Production Risk
High — foreign tables that cannot connect will block any query touching them, potentially causing application-wide failures
A foreign data wrapper could not establish a connection to the remote server. The remote server may be down, unreachable, or refusing connections.
- 1Remote server is not running or is unreachable at the configured host/port
- 2Firewall rules block the connection from the PostgreSQL server
- 3Wrong host, port, or database name in CREATE SERVER options
- 4Remote server max_connections limit reached
- 5SSL certificate validation failure when ssl=require is set
- 6User mapping credentials rejected by remote server
First access to a foreign table backed by an unreachable remote server
SELECT * FROM my_foreign_table;
expected output
ERROR: HV00N: fdw_unable_to_establish_connection
Fix 1
Verify remote server host and port
WHEN Connection refused or timed out
SELECT srvoptions FROM pg_foreign_server WHERE srvname = 'myserver';
Why this works
Corrects misconfigured connection parameters in the foreign server definition
Fix 2
Test connectivity from the PostgreSQL host
WHEN Network or firewall issue suspected
-- From OS: pg_isready -h remotehost -p 5432
Why this works
Confirms whether the remote PostgreSQL port is accessible from the local server
✕ Do not store production credentials in user mappings without encryption
User mapping passwords are visible to superusers via pg_user_mappings
https://www.postgresql.org/docs/current/errcodes-appendix.html
https://www.postgresql.org/docs/current/sql-createserver.html ↗Content generated with AI assistance and reviewed for accuracy. Found an error? hello@errcodes.dev