Returned Leads would be less than batch size even when there are other Leads left

[Anonymous]

Hi all,

My Leads' Ids are from 1 to 32 without 4, 9 and 10. So when I use LeadKeySelector to query out the Leads with ids from 1 to 30, I should get 27 records and the remaining count should be 0.
When I set batch size to be 30, the returned records count is 27, but the remaining count is 1. I'm puzzled.
When I set batch size to be 27, the returned records count is 26 and the remaining count is 2. Then I know there must be something wrong.

I know the exact number of result count, but not all the results are returned. And the newStreamPosition is empty, so I would not get the rest records any more. If I would query for 100 specified ids, I have no idea how different the numbers would be.
What kind of number could help me to get all records down? If my batch size is small, how could I do the get-action for next batch?

Any suggestions?

Thanks,
Biao

[Anonymous]

No only batch size 27, but also from 8 to 26, if I set N to be batch size, I would get N-1 records returned.