Requirements for running graphs within a transaction

If you would like to use outer transactions in your graphs, consider these requirements.

Only one outer transaction can run in an Endeca data store at a time. If you have a graph that starts an outer transaction, such as a graph built with the Transaction RunGraph connector, it is important not to start another graph that attempts to start another outer transaction, otherwise, a transaction fault error is issued.
You can run all components specific to an Endeca data store inside a graph that starts an outer transaction. In other words, all such components in the Integrator are transaction-friendly. When any such component is run within a graph that runs an outer transaction, the underlying update operations from the Web services or Bulk Ingest Interface will reference the outer transaction ID in their calls to the server. This ID is provided to these components by the Transaction RunGraph connector. For the duration of the outer transaction, the connector sets the ID to transaction. In addition, the ID can be specified as a OUTER_TRANSACTION_ID= variable in the worskpace.prm file for your project (notice the empty value). This allows the same components to be used in graphs that do not use transactions, without having to modify worskpace.prm.

Note: All components specific to an Endeca data store can also run in graphs that do not start an outer transaction. If you have a simple implementation, or if a graph that you are creating is light-weight and is not intended for heavy-duty data loading or configuration updates, it can run on its own and does not necessarily need to be run inside an outer transaction.
If you are using a WebServiceClient component in the Integrator that is configured to run any of the Endeca data store Web services, the Request Structure field for the component must include an element OuterTransactionId with an ID value of an outer transaction. This element must be specified first in the request. For example, the following request specified in the Request Structure references the outer transaction ID as a parameter:
```
<config-service:configTransaction 
xmlns:config-service="http://www.endeca.com/MDEX/config/services/types/1/0">
<config-service:OuterTransactionId>${OUTER_TRANSACTION_ID}
</config-service:OuterTransactionId>
...
</config-service:configTransaction>
```
In this example, the string: <config-service:OuterTransactionId>${OUTER_TRANSACTION_ID}</config-service:OuterTransactionId> references the ID of the outer transaction listed in the workspace.prm file for your project.
Consider creating all your data-updating graphs inside a graph that starts and commits an outer transaction.

For more information on outer transaction behavior, see the Oracle Endeca Server Developer's Guide.