MySQL raises EE_UNKNOWN_VARIABLE when you reference a system variable that the server does not recognize.
MySQL Error 67: EE_UNKNOWN_VARIABLE appears when MySQL encounters an unknown system variable in a SET statement, command line option, or my.cnf file. Verify the variable name or upgrade the server to a version that supports it to resolve the issue.
unknown variable '%s'. EE_UNKNOWN_VARIABLE was added in 8.0.13.
MySQL throws error code 67 with the condition name EE_UNKNOWN_VARIABLE when it sees an option or system variable it does not understand. The message reads: unknown variable '%s'. The error was introduced in MySQL 8.0.13 and is global, meaning it can surface during startup or at runtime.
The server stops processing the offending statement or fails to start when the variable appears in configuration files.
Fixing the typo or removing the unsupported option clears the error.
EE_UNKNOWN_VARIABLE is triggered when a SET statement, command line flag, or my.cnf entry includes a variable name that is misspelled, deprecated, or unavailable in the running MySQL version.
Upgrades and downgrades often surface the error because variables change between releases.
Plugins removed from the server also leave behind stale configuration parameters that MySQL no longer recognizes.
Locate the exact variable named in the error message. Cross-check it against SHOW VARIABLES output and the MySQL documentation for your version. Correct the spelling or remove the line if the variable was deprecated.
When the variable is legitimate but new, upgrade the server to a version that supports it.
Always restart MySQL after editing configuration files to verify the fix.
Startup failure: MySQL refuses to start because my.cnf contains innodb_buffer_pool_sizee. Remove the extra e and restart.
Session SET: Application issues SET @@sql_mode='STRICT_PLUS'. Replace with a valid mode or update MySQL 5.7 to 8.0 where the mode exists.
Keep configuration files under version control and validate them in a staging environment before deploying to production.
Use SHOW VARIABLES or SELECT * FROM performance_schema.variables_info to list valid options.
When using Galaxy, its schema-aware autocomplete highlights only supported system variables, reducing typos and deprecation issues during query authoring.
Error 1193 ER_UNKNOWN_SYSTEM_VARIABLE fires for invalid variables in SQL statements prior to 8.0.13. Error 1238 ER_VARIABLE_IS_READONLY appears when attempting to modify a read-only variable. The troubleshooting flow is similar: verify variable name and scope.
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No. The server halts the offending action immediately, so performance is unchanged once the error is resolved.
Ignoring it is risky because MySQL may run with default values that differ from your intended configuration. Always correct the variable.
Run mysqld --help --verbose to validate options without starting the server, or spin up a test instance in Docker.
Galaxy’s context-aware autocomplete lists only valid MySQL variables for the connected version, reducing the likelihood of typos or unsupported options.
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