_last_id = 0
_items_per_page=1000
for row in db(db.table.id>_last_id).select(limitby=(0,_items_per_page),
orderby=db.table.id):
#do something
_last_id = row.id--
_last_id = 0
_items_per_page=1000
for row in db(db.table.id>_last_id).select(limitby=(0,_items_per_page),
orderby=db.table.id):
#do something
_last_id = row.id--