The ER_WARN_BAD_MAX_EXECUTION_TIME warning appears when MySQL cannot enforce the MAX_EXECUTION_TIME hint or variable in the current server version or query context.
ER_WARN_BAD_MAX_EXECUTION_TIME warns that MySQL ignored your MAX_EXECUTION_TIME setting because the feature is unsupported in the current context. Upgrade to MySQL 5.7.8 or higher or remove the hint to resolve the warning.
ER_WARN_BAD_MAX_EXECUTION_TIME
The warning 'Unsupported MAX_EXECUTION_TIME' appears when a SELECT statement includes a MAX_EXECUTION_TIME hint or the session variable max_execution_time but the running MySQL version or storage engine does not support the feature. The server silently ignores the request and returns this warning so you know the limit was not enforced.
MySQL introduced MAX_EXECUTION_TIME in version 5.7.4 but refined support in 5.7.8. Prior releases and certain statement types cannot apply the limit, so the optimizer raises this HY000 warning. Ignoring it can leave runaway queries consuming resources and slowing your application.
The most common trigger is running a query with the MAX_EXECUTION_TIME optimizer hint on a server older than 5.7.8. In 5.7.4-5.7.7 the hint was parsed but not executed, producing the warning.
Another cause is using storage engines or operations that bypass the optimizer, such as derived tables, UNION, or views that disallow the execution timer.
Setting the global or session variable max_execution_time on an unsupported version or inside stored programs compiled on earlier releases also raises the warning.
First confirm your MySQL version with SELECT VERSION();. Upgrade to 5.7.8 or any 8.0 release to gain full support for execution time limits.
If an upgrade is impossible, remove the MAX_EXECUTION_TIME hint or variable from your statements and rely on application-side timeouts or the server parameter max_statement_time in Percona Server.
For queries that involve UNION or views, refactor them into simple SELECT statements or split the logic so the optimizer can apply the timer.
Legacy code migrated from Percona Server often sets max_statement_time. Replace it with MAX_EXECUTION_TIME after upgrading to MySQL 8.0.
Some ORMs automatically inject optimizer hints. Disable the feature in the ORM config or wrap the query in a comment filter before sending to the database.
During ETL jobs Galaxy users can add a guard clause LIMIT 1000 or run the query in the Galaxy editor with a built-in 5-minute kill switch to avoid server-side warnings.
Always test new optimizer hints in a staging environment running the same MySQL version as production.
Use SELECT @@VERSION and SHOW VARIABLES LIKE 'max_execution_time' in deployment checks to block incompatible code.
Leverage Galaxy's AI copilot to suggest version-safe syntax and flag unsupported hints before queries reach production.
ER_UNKNOWN_HINT warns when MySQL does not recognize a hint token. Remove or rewrite the hint.
ER_PARSE_ERROR is thrown when the hint syntax is malformed. Verify comment format /*+ MAX_EXECUTION_TIME(1000) */.
ER_QUERY_INTERRUPTED appears when the execution timer successfully aborts a query. Optimize indexes or batch the workload.
The optimizer can parse but cannot enforce the timer, so it raises ER_WARN_BAD_MAX_EXECUTION_TIME.
UNION, derived tables, and views can bypass the optimizer, preventing the timer from activating.
Setting max_execution_time globally on versions that lack support triggers the warning at runtime.
The server does not recognize the provided optimizer hint token.
The query exceeded its allowed runtime and was aborted by the server.
General syntax error, often due to malformed hint comment structure.
No, the query still runs but without a time limit, so it may consume more resources.
Yes, all 8.0 releases fully support the hint and the max_execution_time variable.
You can run SHOW WARNINGS after the query or set SQL_NOTES=0, but fixing compatibility is recommended.
Galaxy highlights unsupported hints in its editor and suggests version-compatible syntax before execution.
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