<p>Error 1846 indicates that the requested ALTER TABLE clause is not supported for the targeted object or engine.</p>
<p>MySQL Error 1846 ER_ALTER_OPERATION_NOT_SUPPORTED_REASON appears when an ALTER TABLE clause is not supported for the table, partition, or storage engine. Check the reason in the message, adjust the statement, or switch to a compatible engine to resolve the issue.</p>
%s is not supported. Reason: %s. Try %s.
MySQL raises error 1846 when an ALTER TABLE statement includes an option that the server cannot perform on the specified table, partition, or storage engine.
The server returns the message pattern: %s is not supported. Reason: %s. Try %s. Each placeholder explains the unsupported clause, the reason, and a suggested alternative.
The error is triggered when the internal handler for the table engine returns an unsupported flag for the requested alteration.
It frequently appears with partitioned tables, online DDL, or tables running on non-InnoDB engines that lack specific capabilities.
Identify the unsupported clause in the error text, remove or replace it, and rerun the ALTER TABLE.
Alternatively, migrate the table to a storage engine that supports the desired operation and execute the statement again.
Partition management, algorithm=instant requests, and foreign key additions on MyISAM tables commonly fail. Using InnoDB or splitting the change into smaller steps usually works.
Large production tables benefit from Galaxy's versioned query history, letting teams test compatible ALTER statements safely before running them in production.
Always verify engine capabilities with SHOW ENGINE INNODB STATUS or the MySQL manual before crafting DDL.
Use Galaxy collections to store vetted ALTER statements, ensuring teammates reuse proven patterns and avoid unsupported options.
Error 1845 cannot drop partitioning. Error 1847 ALGORITHM=COPY required. Error 1848 ALGORITHM=INPLACE not supported. Each requires removing or changing the conflicting clause.
The table uses MyISAM, MEMORY, or another engine that does not implement the requested ALTER feature.
Certain partitioned-table operations, like ALGORITHM=INSTANT, are unavailable prior to MySQL 8.0.13.
INPLACE or ONLINE keywords may fail when the table has full-text indexes, foreign keys, or virtual columns.
Altering a generated column to STORED or VIRTUAL can be unsupported for the current MySQL version.
Indicates the operation requires ALGORITHM=COPY. Switching algorithms resolves it.
MySQL detected no valid change. Review the ALTER statement.
Named constraints conflict with engine limitations. Remove or rename them.
An active transaction prevents the ALTER. Commit or roll back first.
Newer versions add more online DDL support, reducing Error 1846 frequency. Always check the release notes before relying on new algorithms.
No. The alteration is not applied. You must adjust the statement or engine to proceed.
MySQL suggests a compatible fallback algorithm that always works but locks the table for the duration of the copy.
Galaxy surfaces syntax validation, shows engine metadata, and keeps versioned ALTER statements so teams can iterate until an error-free migration is ready.
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