<p>MySQL raises error 1398 ER_XAER_INVAL when an XA transaction receives invalid arguments or an unsupported command.</p>
<p>MySQL Error 1398 ER_XAER_INVAL occurs when an XA START, END, PREPARE, COMMIT, or ROLLBACK statement uses an invalid XID, repeats a phase, or calls an unsupported option. Correct the XID format, match START and END pairs, and keep InnoDB enabled to resolve the error.</p>
XAER_INVAL: Invalid arguments (or unsupported command)
Error 1398 appears with the message "XAER_INVAL: Invalid arguments (or unsupported command)" whenever MySQL detects a problem in an XA transaction statement. The server immediately aborts the operation and returns SQLSTATE XAE05.
The error means the XA framework rejected the request because one or more arguments are wrong, the command sequence is illegal, or the storage engine cannot interpret the instruction.
The condition arises during XA START, XA END, XA PREPARE, XA COMMIT, or XA ROLLBACK statements. It can occur in standalone MySQL servers or within distributed transactions managed by external coordinators.
Developers often see it while testing two-phase commit flows, integrating message queues, or recovering orphaned XA transactions.
An unresolved ER_XAER_INVAL prevents the affected global transaction from completing. Holding locks may block other sessions, grow undo space, and degrade performance. Production workloads using microservices or message brokers can stall.
Fixing the error promptly restores atomic consistency across the participating systems and keeps the InnoDB transaction log healthy.
MySQL throws ER_XAER_INVAL when it receives invalid arguments, an unsupported XA statement, or an illegal sequence. Typical triggers include malformed XIDs, mismatched formatID or gtrid lengths, and issuing XA PREPARE twice.
Unsupported features, such as a JOIN of XA and non-XA statements in one transaction, can also raise the condition.
Verify the XID parts, ensure each XA START is paired with XA END, and follow with XA PREPARE then XA COMMIT. Enable the InnoDB engine and restart stalled transactions cleanly. The next section shows working SQL fixes.
Scenario: XID too long. Solution: truncate gtrid and bqual to 64 bytes or less.
Scenario: Duplicate XA START. Solution: issue XA END before restarting.
Scenario: InnoDB disabled. Solution: install plugin or set default_storage_engine=InnoDB.
Always validate XID format client-side, wrap XA calls in stored procedures, and monitor INFORMATION_SCHEMA.INNODB_TRX for orphaned entries.
Galaxy users can store vetted XA statements in shared collections, ensuring team-wide reuse of correct patterns and preventing ad-hoc mistakes.
ER_XA_RMFAIL (1399) signals resource manager failure during an XA operation. Reconnect and retry once.
ER_XAER_NOTA (1397) indicates an unknown XID. Check spelling and lifetime of the global transaction.
Using an XID with illegal length or characters instantly triggers ER_XAER_INVAL.
Starting a transaction twice or preparing before ending breaks the required order.
Running XA commands while InnoDB is disabled or using MyISAM tables raises the error.
Providing too many or too few arguments in the XA statement causes immediate rejection.
Old connectors may send deprecated flags unsupported by the server, leading to the condition.
Raised when the server cannot find the supplied XID, often due to typos or expired transactions.
Signals resource manager failure. Usually transient and resolved by retrying.
Indicates an internal resource manager error requiring admin attention.
Shows that the distributed transaction has been rolled back automatically.
The XID may be malformed, duplicate, or too long. Verify formatID, gtrid, and bqual lengths.
Yes, but distributed transactions will not work. Instead, fix the argument issues to maintain atomicity.
Query INFORMATION_SCHEMA.INNODB_TRX or run SHOW ENGINE INNODB STATUS to list pending XA entries.
Galaxy lets you run, share, and version XA statements in its editor, making it easier to spot invalid sequences.
.avif)
.avif){kind=logo}
