<p>The error appears when you attempt to change transaction characteristics (isolation level, access mode) while a transaction is already active.</p>
<p>MySQL Error 1568: ER_CANT_CHANGE_TX_CHARACTERISTICS occurs when a session tries to alter transaction isolation level or read/write mode while a transaction is open. Finish the current transaction with COMMIT or ROLLBACK, then issue SET TRANSACTION or START TRANSACTION WITH clauses to resolve the problem.</p>
Transaction characteristics can't be changed while a
MySQL raises this error with SQLSTATE 25001 when you execute SET TRANSACTION or START TRANSACTION WITH clauses after a transaction has already begun. The server disallows changing isolation level or read-only status mid-transaction to protect ACID guarantees.
The message Transaction characteristics can't be changed while a transaction is in progress means the session is inside an open transaction. You must first complete that transaction before modifying its traits.
The most common trigger is calling SET TRANSACTION ISOLATION LEVEL or SET SESSION TRANSACTION READ ONLY after issuing a data-manipulating statement that implicitly starts a transaction when autocommit is off.
Another cause is wrapping business logic in frameworks that issue BEGIN; then later attempt to alter isolation level for a specific query, not realizing the transaction is already live.
The quick fix is to terminate the current transaction with COMMIT or ROLLBACK, then run your SET TRANSACTION statement before starting the next unit of work.
If you need different isolation levels for different statements, break the workflow into separate transactions, each with its own characteristics defined at the very beginning.
Dockerized test suites often disable autocommit, run migrations, and then try to lower isolation for bulk inserts. Commit after migrations, apply SET TRANSACTION, and reopen a new transaction for the inserts.
In stored procedures, check @@autocommit and call COMMIT before issuing SET TRANSACTION commands to avoid the error during complex data loads.
Always set isolation level and access mode as the first statement in a new transaction. Place SET TRANSACTION lines directly before BEGIN or START TRANSACTION to guarantee compliance.
Enable explicit autocommit in ad-hoc scripts to prevent hidden transactions and to keep characteristic changes predictable.
Error 1305 PROCEDURE does not exist - verify schema and routine names before execution.
Error 3572: ER_NOT_SUPPORTED_AUTH_MODE - upgrade authentication plugin or client library to match server settings.
Disabling autocommit starts an implicit transaction after the first statement, making later SET TRANSACTION commands illegal.
Frameworks or ORMs may open a transaction automatically, so subsequent characteristic changes fail.
Procedures that mix DML and isolation tweaks without committing between them encounter the 1568 error.
Pooled connections may inherit an open transaction from a previous request, blocking characteristic changes.
Raised when attempting to modify a read-only system variable; solved by changing scope or server config.
Indicates the user exceeded max_user_connections; fix by pooling or raising the limit.
Occurs when transactions deadlock; resolve by retry logic or changing isolation levels.
No. MySQL forbids altering isolation level or read/write mode once a transaction has begun, resulting in Error 1568.
With autocommit on, each statement is its own transaction, so SET TRANSACTION commands run before the next statement and avoid Error 1568.
Many ORMs automatically open a transaction then attempt to set isolation for specific queries, unknowingly violating MySQL rules.
Yes. Galaxy shows session status and highlights uncommitted changes, letting you commit or rollback before altering characteristics.
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