Thanks for posting your question in the Microsoft Q&A forum.
For tables with more than 1024 pages:
The default sampling rate is calculated using the formula:
(15 * power(Rows, 0.55) / TotalRows * TotalPages + 1024) / TotalPages
Where:
-
Rows
is the total number of rows in the table -
TotalRows
is the total number of rows in the table -
TotalPages
is the total number of pages in the table
This formula ensures that at least 1024 pages are sampled, even if the calculated sampling rate is less than that.
For tables with less than 1024 pages:
If the table has less than 1024 pages in the clustered index (or index ID 0 if the table is a heap), SQL Server ignores the sample rate specified and always uses a 100% sampling rate.
Please don't forget to close up the thread here by upvoting and accept it as an answer if it is helpful