Rather than extract the entire data source, you can instead take a sampling of rows. You can also define a set of specific set of data to include and then extract just a sample of them using the Number of Rows settings. Follow the instructions below to specify a subset of the data based on the number of rows.
Step 1
In the Extract dialog box, optionally specify filters using the instructions above. Then specify the number of rows to include. You can select all, a percentage, or a specific number of rows. Depending on the data source, an additional dropdown menu with further options for a percentage or specific number or rows may be available.

Step 2
When finished click Extract, and save the extract under a descriptive name.
The icons in the Data window indicates that you are now connected to an extract file.

Note: While creating extracts is a great way to access subsets of information from large data sources offline. You can also use it to add advanced functionality to limited data bases and improve performance.