Error
Error Code:
1412
MySQL Error 1412: Table Definition Changed
Description
This error indicates that a transaction attempted to access or modify a table whose structure (definition) was altered by another operation concurrently. It often occurs in highly concurrent environments where Data Definition Language (DDL) statements run alongside Data Manipulation Language (DML) or select queries.
Error Message
Table definition has changed, please retry transaction
Known Causes
3 known causesConcurrent DDL Operations
Another session or application performed a DDL operation (e.g., ALTER TABLE, DROP TABLE, RENAME TABLE) on the target table while your transaction was active.
Long-Running Transactions
Transactions that run for an extended period are more likely to encounter DDL changes on the tables they access, leading to this error when the definition no longer matches.
Stale Metadata Caching
Application connectors or database proxies might cache table metadata. If not refreshed promptly after a DDL change, they can provide outdated information to subsequent queries.
Solutions
4 solutions available1. Retry the Transaction easy
The simplest solution is to re-execute the operation that caused the error.
1
Identify the SQL statement or sequence of statements that triggered the error.
2
Re-execute the same SQL statement(s) exactly as they were before. If the error was transient due to a brief table definition change (e.g., by another session), retrying should resolve it.
-- Example: If you were trying to INSERT data and got the error:
INSERT INTO your_table (column1, column2) VALUES ('value1', 'value2');2. Restart the MySQL Client or Application easy
Restarting the client or application that's interacting with the database can clear its internal state.
1
Close the MySQL client application (e.g., MySQL Workbench, DBeaver, a command-line client) or the application that is performing database operations.
2
Re-open the client or restart the application.
3
Attempt the operation again. This helps if the client itself is holding an outdated schema definition.
3. Check for Concurrent DDL Operations medium
Investigate and resolve simultaneous Data Definition Language (DDL) changes.
1
Identify if any other sessions or processes are actively performing DDL operations (like `ALTER TABLE`, `CREATE TABLE`, `DROP TABLE`, `TRUNCATE TABLE`) on the affected table or related tables while your transaction is running.
SHOW PROCESSLIST;2
Examine the `INFO` column in the `SHOW PROCESSLIST` output for DDL statements. Look for long-running DDL operations.
3
If concurrent DDL is found, either wait for it to complete or, if possible, coordinate to avoid simultaneous DDL and data manipulation operations. This might involve scheduling changes during maintenance windows.
4
Once concurrent DDL is resolved, retry your original transaction.
4. Refresh Schema Cache (If Applicable) medium
For some connectors or ORMs, explicitly refreshing the schema cache can resolve this.
1
Consult the documentation for your specific MySQL connector (e.g., JDBC, Python's `mysql.connector`, PHP's `mysqli`) or Object-Relational Mapper (ORM) (e.g., SQLAlchemy, Hibernate, Eloquent).
2
Look for methods or configurations related to schema caching and explicitly call a 'refresh', 'clear', or 'reload' method for the relevant schema or connection.
// Example for a hypothetical Python connector
connection.clear_schema_cache()
3
After clearing the cache, re-attempt the transaction.