First, it should be pointed out that if the table gets updated between calls like this (even fixed for the lack of use of m) isn't going to always get all the rows of the table or a snapshot at a given time unless the whole thing is wrapped in a transaction. And once you wrap it in a transaction, you might as well just select all the rows at once and then just step to fetch them n at a time, do what you were planning on doing then step the next n.