Coordinator Failure and Restart

If the coordinator restarts during a global transaction, due to shutdown, failover or server failure, transaction behavior depends on the user-defined timeout and the command being executed.

Communication to Coordinator Resumes Before Timeout
Command Status	Command Behavior	Result
Actively executing command	Command suspends and transfers control to server, except for ROLLBACK, which executes locally on writer.	Commands succeed
New DML command	Command suspends and transfers control to server. ROLLBACK and ROLLBACK TO SAVEPOINT execute locally instead of suspending.	Commands succeed

Communication Failure Exceeds Timeout
Command Status	Command Behavior	Result
Suspended DML command on connection	The suspended command fails and returns an error.	Transaction rolls back
No suspended DML command on connection	The next command returns an error.	Transaction rolls back

For example, if a transaction suspends and the write server becomes inaccessible, you can roll back the transaction to release resources held by the coordinator for suspended transactions belonging to that writer.