If i only count the deleted rows, the problem is the same, and the server hangs while performing garbage collection.

On the other hand, if I count the rows not deleted, no garbage collection is performed - that makes sens as the index on created makes sure that no delete records/rows are accessed. This is useful to know as i can make sure that other parts of the application never issues a query for rows older that 6 months.

Now the garbage collection will be deferred and happen during backup. Is it possible that the same "hang" behavior will happen during backup as a result of the deferred garbage collection?