WPSolr uses external search engines to search WordPress data, and to do that they first need to store it. The “2.2 Data” page is used to determine which data you wish to index.
Select the “2.2 Data” tab
Select the index
Be sure to select the index in which you wish to store the data. You can select which one you want from a drop-down list.
Stop real-time indexing
If you do not wish to index a document as soon as it is created or modified, you should check this box. You could then manually index the data in bulk using the “3. Send data” page or use the Cron scheduling add-on.
Otherwise, you should leave it unchecked.