PostgreSQL raises fdw_unable_to_establish_connection (SQLSTATE HV00N) when a foreign data wrapper cannot open a network session to the remote server.
fdw_unable_to_establish_connection occurs when PostgreSQL’s foreign data wrapper cannot reach the remote host. Check host, port, SSL, firewall, and authentication settings, then retry the connection.
PostgreSQL Error HV00N
PostgreSQL throws error code HV00N fdw_unable_to_establish_connection when a foreign data wrapper (FDW) tries to open a network connection to a remote database but fails. The server cancels the statement immediately.
The failure halts SELECT, INSERT, UPDATE, or DELETE operations that rely on a foreign table. Resolving it quickly restores cross-database queries and keeps ETL pipelines healthy.
Invalid host or port details prevent the FDW from finding the remote server.
Typos, DNS issues, or port changes are common culprits.
Network blocks such as firewalls, VPN outages, or security groups can silently drop packets, triggering the error.
SSL or TLS mismatch between PostgreSQL and the target server rejects the handshake, causing an immediate connection failure.
Authentication errors occur when the FDW uses the wrong user, password, or certificate, stopping the session before it starts.
Confirm the remote host and port with ping or telnet.
Update the foreign server definition if values changed.
Open necessary ports in firewalls or cloud security groups. Ensure the PostgreSQL instance can reach the destination subnet.
Align SSL modes on both sides. If the remote server requires SSL, set options (sslmode, sslcert) in the FDW connection string.
Update user mappings with the correct credentials. Rotate expired passwords or certificates in secrets managers.
Failing after a database migration usually means the host or port changed.
Redeploy the FDW definition with new endpoints.
Sporadic failures during peak traffic often point to connection limits. Increase max_connections on the remote server or use connection pooling.
An upgrade that enforces TLS v1.2 can break older clients.
Recompile or update postgres_fdw with compatible OpenSSL libraries.
Store foreign server credentials in environment variables or a secrets vault to simplify rotations.
Use health-check queries in Galaxy’s SQL editor to alert on connection latency or failures before production jobs run.
Document foreign server endpoints in Galaxy Collections so teams update queries consistently after infrastructure changes.
HV00P fdw_error—general FDW failures often mask configuration mismatches.
08001 sqlclient_unable_to_establish_sqlconnection appears when PostgreSQL itself cannot reach any remote host.
57P01 admin_shutdown is raised if the remote server restarts mid-query.
Reconnect after the restart.
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Not always. It can also result from wrong host details, blocked ports, or SSL mismatches.
Yes. Wrap queries in PL/pgSQL with exception handling and exponential backoff, or use a job orchestrator.
No. Any FDW that opens a network session, such as mysql_fdw or oracle_fdw, can raise the same error.
Galaxy’s connection tester flags unreachable hosts during query authoring, preventing fdw_unable_to_establish_connection in production.
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