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5.2. AutoCommitTxn Execution Property
Since user level commands may execute multiple source commands, users can specify the AutoCommitTxn execution property to control the transactional behavior of a user command when not in a local or global transaction.
| Setting | Description |
|---|---|
| OFF | Do not wrap each command in a transaction. Individual source commands may commit or rollback regardless of the success or failure of the overall command. |
| ON | Wrap each command in a transaction. This mode is the safest, but may introduce performance overhead. |
| DETECT | This is the default setting. Will automatically wrap commands in a transaction, but only if the command seems to be transactionally unsafe. |
The concept of command safety with respect to a transaction is determined by Red Hat JBoss Data Virtualization based upon command type, the transaction isolation level, and available metadata. A wrapping transaction is not needed if any of the following is true:
- A user command is fully pushed to the source.
- The user command is a SELECT (including XML) and the transaction isolation is not REPEATABLE_READ nor SERIALIZABLE.
- The user command is a stored procedure and the transaction isolation is not REPEATABLE_READ nor SERIALIZABLE and the updating model count is zero.
The update count may be set on all procedures as part of the procedure metadata in the model.
