The maximum limit for the length of the QueryText property of FullTextSqlQuery is 4096 characters.

Requirement:

• I was working on case, where Customer's business requirement was to have the length of the QueryText property of FullTextSqlQuery to be UNLIMITED.

Troubleshooting:

1. Moment the code touches the limit of about 4093 it throws the error
2. Error: Specified argument was out of range of valid values; _COMPlusExceptionCode -532459699
3. Occurs When: Error comes when trying to assign the string value to the QueryText property itself.
4. Took help from our Escalation engineer Nishandv, to know the exact hard-code limit (if any) in SharePoint for QueryText property of FullTextSqlQuery object

Resolution / WorkAround:

• When using FullTextSqlQuery objects for search; make sure the length of the QueryText Property do not exceed 4096 characters

Reference :

• Nishand's blog for reference: https://blogs.msdn.com/nishand/archive/2008/10/02/fulltextsqlquery-with-querytext-length-gt-4096-throws-argumentoutofrange-exception.aspx