<p>The connection string supplied for a foreign data source is malformed, so MySQL rejects the statement with error 1433 ER_FOREIGN_DATA_STRING_INVALID.</p>
<p>MySQL Error 1433 ER_FOREIGN_DATA_STRING_INVALID appears when a CREATE SERVER or ALTER SERVER statement contains a malformed connection string. Correct the URI format or key-value pairs in the OPTIONS clause to resolve the error and successfully connect to the external data source.</p>
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MySQL raises error 1433 with condition ER_FOREIGN_DATA_STRING_INVALID when it cannot parse the connection string supplied in a CREATE SERVER, ALTER SERVER, or CREATE TABLE ... ENGINE=FEDERATED statement. The string might miss required parts such as scheme, host, port, user, or password.
The server stops execution because an invalid string means MySQL cannot reach the foreign data source. Until the string is corrected, any dependent foreign tables will remain unusable.
The most common trigger is a typo or omitted element in the URI-like connection string, for example mysql:// or https:// segments. Extra spaces or unsupported characters can also break parsing.
Version mismatches between the MySQL FDW plugin and the syntax used in the string may cause the server to interpret otherwise valid text as invalid.
Validate the connection string against MySQL documentation. Ensure it follows the pattern scheme://user:password@host:port/database or the key=value list required by the specific storage engine.
Apply the corrected string with ALTER SERVER for an existing definition or recreate the server object. Test the connection before querying federated tables.
When migrating from MariaDB FEDERATEDX, users sometimes keep the old connection string mysql://user@host/db without a password. Adding :password or using a named OPTIONS parameter solves the problem.
Automated scripts that build connection strings by concatenation can yield double slashes (mysql:////host/db), triggering the error. Sanitizing input and adding validation checks avoids malformed output.
Store connection strings in environment variables or a secrets manager and validate them with a regex before applying them in DDL statements.
Use parameterized deployment scripts where each part of the string is explicitly defined and tested, preventing accidental omission.
Error 1429 ER_FOREIGN_DATA_SRC_INVALID indicates that the foreign data source itself is unreachable, separate from the string format problem. Ensure network and credentials are correct.
Error 1428 ER_FOREIGN_DATA_STRING_TRUNCATE occurs when the connection string exceeds the maximum length. Shorten the string or increase the allowed length if possible.
Omitting mysql:// or another scheme leads the parser to assume the string is malformed.
Using backticks or extra slashes within the string confuses the FDW parser and results in error 1433.
Invisible whitespace, line breaks, or non-UTF-8 characters can invalidate the connection string.
Specifying an option that the chosen storage engine does not recognise causes MySQL to reject the entire string.
Occurs when the connection string is longer than the allowed limit, requiring a shorter string or settings adjustment.
Appears when the foreign data source is unreachable or unspecified, even when the string format is correct.
Indicates that the specified storage engine does not match the foreign data source type.
No. MySQL validates connection strings at parse time for security reasons. Always supply a correct string.
Yes. Error 1433 is part of the core server code and appears in all editions that support federated or foreign data connections.
Galaxy highlights invalid connection strings in real time, offers AI-powered suggestions, and lets teams endorse the corrected DDL statements to avoid repeated mistakes.
A password is not strictly required, but omitting it often causes authentication failures later. Include it or rely on secure OPTIONS parameters.
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