In SharePoint 2013, we have a content source that connects via BCS. The total items in the External table are around 7.7 million records. We have a full crawl scheduled to crawl the BCS items every month and an incremental crawl to run every 4 hrs.

In our environment the full crawl takes 18 hrs to crawl 7.7 million records and incremental crawl takes 2-3 hrs based on the number of items modified in the external table.

Things were moving fine until the incremental crawl deleted all the indexes from the content source when it failed (due to permission issue) to crawl BCS items. When we checked the crawl log we found that the incremental crawl only triggered the delete operation in the SharePoint Search Service.

Finally we came to know that Microsoft enforced some policies in SharePoint Search Service to delete the index based on some conditions. I am not sure we can disable this setting but we can increase the thresholds through PowerShell.

If somebody knows how to disable this setting / policy let me know….

Solution / Workaround

Find the below article which explains about this issue:

https://docs.microsoft.com/en-us/previous-versions/office/sharepoint-server-2010/hh127009(v=office.14)?redirectedfrom=MSDN

But few intervals are changed in 2013 version of SharePoint

Comparison of Default Values between 2010 and 2013:

Thanks to Simon’s blog for sharing this information in his blog.

Property SP 2010 SP 2013
ErrorDeleteCountAllowed 30 times 10 times
ErrorDeleteIntervalAllowed 720 hours 240 hours
ErrorCountAllowed 100 times 15 times
ErrorIntervalAllowed 1440 hours 360 hours
RecrawlErrorCount 10 times 5 times
RecrawlErrorInterval 360 120 hours
DeleteUnvisitedMethod 1 1