<p>The server rejects an ALTER statement because the requested clause or algorithm is not supported for the targeted table or storage engine.</p>
<p>MySQL Error 1845: ER_ALTER_OPERATION_NOT_SUPPORTED occurs when an ALTER statement requests an unsupported clause or algorithm. Rewrite the statement with a supported ALGORITHM or remove the clause to resolve the problem.</p>
%s is not supported for this operation. Try %s.
The error appears when you run ALTER TABLE or another DDL command that specifies an option MySQL cannot execute on the selected table or storage engine. The message returns as "%s is not supported for this operation. Try %s."
MySQL added this safeguard in version 5.7.1 to prevent online DDL attempts that could corrupt data or hang the server. Fixing it quickly restores schema change continuity and CI pipelines.
The option ALGORITHM=INPLACE or ALGORITHM=COPY may not be available for certain storage engines, partitioned tables, or column types, triggering the error.
Unsupported clauses such as LOCK=NONE, ADD SPATIAL INDEX, or virtual column modifications on earlier MySQL versions also raise error 1845.
First, check the storage engine and MySQL version to confirm which algorithms the server accepts. Switch to a supported ALGORITHM or omit it entirely.
If the table uses features that block online DDL, refactor the schema change into smaller compatible steps or use a tool like gh-ost to run nonblocking migrations.
Adding a FULLTEXT index on an InnoDB table with ALGORITHM=INPLACE fails. Remove the algorithm hint or use ALGORITHM=COPY to succeed.
Altering a partitioned table column with LOCK=NONE is unsupported. Drop LOCK=NONE or switch partitions to InnoDB and retry.
Always consult INFORMATION_SCHEMA.INNODB_SYS_TABLES and SHOW CREATE TABLE to confirm storage engine capabilities before issuing DDL.
Use tooling like Galaxy's AI copilot to autocomplete ALTER statements with only valid clauses based on live metadata, preventing unsupported options from reaching production.
Error 1846 ER_ALTER_OPERATION_NOT_SUPPORTED_REASON specifies a reason code when only part of an operation is unsupported. Address the listed reason and rerun.
Error 1064 SQL syntax error surfaces when the clause itself is written incorrectly rather than unsupported. Correct the syntax to proceed.
ALGORITHM=INPLACE or COPY is not implemented for the target table or engine.
LOCK=NONE cannot be granted because the change requires a higher lock.
MyISAM, partitioned, or temporary tables lack online DDL support.
Adding SPATIAL or FULLTEXT index on certain columns fails under online DDL.
Provides a reason code clarifying why the requested option is not supported.
Appears when partitioned table operations fail due to handler issues.
Raised when the ALTER statement itself contains invalid syntax.
No. MySQL silently downgrades or rejects operations that cannot run in place. Forcing it risks data corruption.
Upgrading often expands online DDL support, but some limitations remain. Test each change after upgrade.
Galaxy's AI copilot inspects table metadata and only suggests ALTER clauses your database version supports, eliminating trial and error.
gh-ost is widely trusted, but you must test on staging, monitor replication lag, and ensure triggers or foreign keys do not interfere.
.avif)
.avif){kind=logo}
