Fixed Iterator Component
Loop over values of a simple sequence.
This component implements a simple loop over rows of fixed data values.. It enables you to run an attached component multiple times, each time with different values set on any number of variables. Those variable can be referenced from the attached component.
To attach the iterator to another component, use the blue output connector and link to the desired component. To detach, right click on the attached component and select 'Disconnect from Iterator'.
If you need to iterate more than one component, put them into a separate orchestration or transformation job and use a Run Transformation or Run Orchestration component attached to the iterator. In this way, you can run an entire ETL flow multiple times, once for each row of variable values.
Note: All iterator components are limited to 5000 iterations.
|Name||Text||The descriptive name for the component.|
Sequential - Iterations are done in sequence, waiting for each to complete before starting the next.
This is the default.
Concurrent - Iterations are run concurrently. This requires all "Variables to Iterate" to be defined as Copied variables, so that each iteration gets its own copy of the variable isolated from the same variable being used by other concurrent executions.
Note: The maximum concurrency is 8 times the number of processors on your cloud instance. For example: An instance with 2 processors has a maximum concurrency of 16.
|Variables to Iterate||Multi-select||Choose one or more existing variable to iterate. (You may need to define them first in the Project-->Manage Environment Variables screen.)|
|Iteration Values||Variable 1||Enter as many rows as you require. Each row becomes an iteration.|
|Variable n||For each Variable chosen in "Variables to Iterate", provide a value for that iteration..|
|Break on Failure||Select||
No: Attempt to run the attached component for each iteration, regardless of success or failure.
Yes: If the attached component does not run successfully, fail immediately.
Note: If a failure occurs during any iteration, the failure link is followed. This parameter controls whether it is followed immediately or after all iterations have been attempted.
Note: This is only available in Sequential mode. When running with concurrency, all iterations will be attempted.
This component makes the following values available to export into variables:
|Iteration Attempted||The number of iterations that this component attempts to reach (Max Iterations parameter).|
|Iteration Generated||The number of iterations that have been initiated. Iterators terminate after failure so this number will be the successful iterations plus any potential failure.|
|Iteration Successful||The number of iterations successfully performed. This is the max iteration number, minus failures and any unattempted iterations (since the component terminates after failure).|
This example iterates through two different airlines, and two different US States. For each of those 4 combinations, a transformation job is run. The variables are available to use in that transformation job to filter the incoming data.
We need to define the variable we intend to iterate, and provide some sensible default values.
In the configuration for the Iterator, the two variables are selected and each combination of EI (Aer Lingus), BA (British Airways) carriers, and CA (California) and PA (Pennsylvania) states are entered.
When the transformation runs, the AnalyseFlightData transformation job is executed 4 times, each time setting the carrier_code and state variables.
An alternative configuration would be to nest two Fixed Iterators together, iterating the values for carrier_code in the first, and state in the second.