Execution Rules

Resources

In Oracle databases, it can be prevented that too much parallel activity consumes the entire temp space and thereby causes tasks to be aborted by the database. To prevent this, you can specify how much maximum temp space is available in the database. For each task, it is stored how much temp space it used during execution. When a task is to be started, it is checked whether the sum of the temp space requirement of the currently running tasks plus the temp space consumption of the last execution exceeds the total available temp space. If this is the case, this task will not be started.

Execution Order

Transformations are executed in the following order (evaluation is done in the specified order):

• Priority (see below)
• Runtime. Transformations that have run longer in the past are started earlier
• Sequence number of the transformation (sqts_action_id)

Priority

A priority can be assigned to a batch element and also to a connection. This is used when there are more waiting transformations than free processes. Transformations with higher priority (= lower number) are then preferred.

When you set a priority for a connection, all tasks that use this connection receive the same priority. This achieves in the DWH that all tables of a source are transferred at approximately the same time. By using different priorities for the respective connections, you can control the order in which data is loaded.

Since this method does not create dependencies (i.e. instead of artificial layer dependencies), everything is always processed as far as the dependencies between the individual transformations allow, even if higher-priority transformations have failed or depend on failed transformations.