<p>MySQL cannot open a network connection to the foreign data source defined by a FEDERATED table or CREATE SERVER, halting the query.</p>
<p>MySQL Error 1429 ER_CONNECT_TO_FOREIGN_DATA_SOURCE means the server failed to reach the specified foreign data source for a FEDERATED table or remote server definition. Check host, port, authentication, firewall rules, and plugin configuration to quickly restore connectivity.</p>
Unable to connect to foreign data source: %s
MySQL raises this error when it tries to access a foreign data source through a FEDERATED table, CREATE SERVER object, or mysql_fdw plugin and the network connection cannot be established.
The server stops the query and returns SQLSTATE HY000, signaling a generic runtime failure rooted in connectivity.
Most failures trace to unreachable hostnames, closed ports, wrong credentials, or disabled network plugins. MySQL must successfully perform a TCP handshake before any authentication begins.
Server-side limits like max_connections or SELinux policies can also block the outbound connection attempt, triggering the same error code.
Verify the foreign host is online, accepts TCP on the defined port, and allows the connecting MySQL user. Test with telnet or nc before retrying the query.
Update or recreate the SERVER object or FEDERATED table with the correct HOST, PORT, USER, and PASSWORD options. Flush privileges to ensure changes apply.
If a firewall recently changed, open the remote port and repeat the connection test. A VPN split-tunneling rule may also be required in corporate environments.
When migrating databases, confirm that the new target accepts remote connections from the source IP range; editing bind-address or skip-networking in my.cnf often resolves hidden blocks.
Store connection parameters in a central configuration file and reuse them across FEDERATED objects to minimize typos and drift.
Automate health checks that run SELECT 1 on each foreign server hourly and alert when latency or connection failures spike.
Error 1425 ER_CANT_OPEN_FOREIGN_DATA_FILE appears when MySQL can connect but lacks file-level access. Grant FILE privilege to fix.
Error 1478 ER_INNODB_FT_INDEX_TABLE lacks full-text index support; enabling the innodb_ft_enable_stopword option usually clears it.
The hostname or port in the FEDERATED or SERVER definition is wrong or unreachable.
Outbound firewalls, security groups, or VPN rules block the connection attempt.
The remote MySQL instance rejects the supplied user or password before handshake completes.
The FEDERATED storage engine or required plugin is disabled in the local MySQL server.
max_connections or SELinux policies prevent new outbound sockets from opening.
Raised when MySQL connects but cannot access the referenced data file; grant FILE privilege or fix file path.
Authentication fails for the supplied user; verify GRANT statements and passwords.
Client-side error indicating the TCP handshake to the MySQL instance failed; similar root causes but triggered from a client program.
Primarily yes, but any feature that relies on CREATE SERVER objects, including some ETL tools, can trigger it.
All GA releases that include the FEDERATED engine, starting from MySQL 5.0, can raise the error.
Galaxy s connection tester validates host, port, and credentials before you save a FEDERATED table, catching most issues early.
Yes. The MySQL error log records ER_CONNECT_TO_FOREIGN_DATA_SOURCE with additional system error codes for deeper diagnosis.
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