...

• In some cases, the Initial Data sample is the entire dataset. 

  Data from the rest of the first file or table or from other files or tables is not included in the data grid.
  

  Tip
  Tip: For purposes of loading the data, the initial data sample is generated and displayed at first. For a better representation of the entire dataset, you should create a new sample.

• In other cases, the Initial Data sample is generated from a collection of files. For more information on this special sampling type, see Overview of Sampling.

To create a new sample, click Collect a new sample.

...

• Initial Data: By default, the application loads the first N rows of the dataset as the initial data sample when the Transformer page is opened. The number of rows depends on column count, data density, and other factors. If the dataset is small enough, the full dataset is used. 

  Info
  NOTE: By default, samples may be up to 10 MB in size or may be limited based on the maximum number of files that can be scanned. For datasets smaller than this limit, the entire dataset is loaded. See Overview of Sampling.

• Click the link in the current sample card to see the list of all available samples.

  Tip
  Tip: To change the name of a sample, click its card in the list of all available. Then, click the Edit icon.

...