Important note you may not know:
What Is Query Throttling (different meaning)?
The list view threshold does not apply simply to the number of results returned by your query. Instead, it restricts the numbers of database rows that can be accessed in order to complete execution of the query
What does it mean?
suppose you are working with a list that contains 10,000 items. If you were to build a query that returns the first 100 items sorted by the ID field, the query would execute without issue because the ID column is always indexed. However, if you were to build a query that returns the first 100 items sorted by a non-indexed Title field, the query would have to scan all 10,000 rows in the content database in order to determine the sort order by title before returning the first 100 items. Because of this, the query would be throttled, and rightly so—this is a resource-intensive operation.
