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Make sure each source, transformation, and sink do not have any errors.
Click Preview.
Notice that the task bar changes and there are three new buttons: Run, Duration, and Logs.Optionally, you can click Configure to change the configuration following settings before running Preview. You can modify the following settings:
Runtime arguments.
Preview config. You can change the number of rows to preview.
Advanced options. You can change Pipeline config and Engine config.
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4. Click Run to start the preview job.
While the pipeline is running in preview mode, no data is actually written to the sink, but you will be able to confirm that data is being read properly and that it will be written as expected once the pipeline is deployed.
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