Use of Commit/Rollback with Multidatabase Transactions
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The use of COMMIT (or ROLLBACK) should not be used once you start a multi-database transaction with the IB API.
When you perform an execute immediate COMMIT [or ROLLBACK] statement [DSQL] for one of the databases, you will have an inconsistent state. Also, if you then call the IB Commit API, you will get an invalid transaction handle from the database whose transaction had already been committed.