SharePoint 2016 Search Results 
Disclaimer: The information below can be specific to particular SharePoint environmental issues. The workarounds may or may not be suitable for your environment. Please consult your SharePoint Administrator before performing any changes to your SharePoint production environment.

Protocol handler that crawls the SharePoint content will not populate ows_created_x0020_Date(Text) crawled property.

1.

How to map CreatedDate field to crawled field?

  • Open Central Administration, in the Application Management section, click Manage service applications. 
  • Click the Search service application for which you are viewing managed and crawled properties.
  • On the Search Administration page, in the Quick Launch, under Queries and Results, click Search Schema.
  • On the Metadata Property Mappings page, click New Managed Property.
  • On the New Managed Property page, in the Property name box in the Name and type section, type the name of the new managed property.
  • In the Description box, type a description of the property.
  • Under The type of information in this property, select one of the following options for the property:
  • Under The type of information in this propertyText type
  • Check Queryable, Retrievable, Refinable properties.
  • In the Mappings to crawled properties section, select Include content from the first crawled property that is not empty, based on the specified order
  • Click Ok

2..

How crawling will affect export process of search results?

For example, if you perform search for the search query, Author='John Doe' using Trial Search dialog, the search results may contain 1205 records approximately. During export process, search results count may increase to 1250 records approximately due to the incremental crawling of the content source.

3.

How to avoid the "System.Services.TimeoutException" during export process of search results in SPListX?

During frequent usage of SharePoint, SharePoint Search services cannot serve the search request within the stipulated time therefore, SharePoint search server itself throws an System.ServiceProcess.TimeoutException. To avoid this exception, we strongly recommend you to perform search export process during off-peak hours.

4. What is meant by Trimming Duplicate Search Results?
To specify whether duplicate list item URLs should be removed from search results.
5. How to view duplicate search results in SharePoint  2016?
  • Go to the search page; enter any query to return the search results page. For example: enter keyword 'sharepoint' in any keywords text box..
  • Under Site Actions, select 'Edit page'
  • Locate the 'Search Core Results' web part (usually in the bottom zone)
  • From the Edit button, select 'Modify shared web part
  • In the task pane that appears on the right hand side, under 'Settings', check the box labeled ' Show view Duplicates links '.