There is no cache of query results when you use cursors - or
limit/offset. They're just pointers into the real datastore index.
If you change the datastore, the results will change.
If you want 100% guaranteed unchanging query results in a highly
dynamic dataset, cache the results yourself in the
let say we use cursor and we fast-forward page.
1-10
11-20 when reached here, one record in 23 is deleted
21-30
on in this case, when cursor is at 21, it will only show 9 record on
this page correct?
In other words, we cannot use global count (total records) for paging
unless we will have to
