Howdy. I've recently started using monetdb and was testing out the

python3-monetdb module with the 'quick start' voc dataset. I'm not

grokking the purpose of cursor.scroll() if it's working as

intended. I am getting weird (to me) results, which I'm including

below.

Running 11.17.17-20140514 of the server, client, and python module

under Ubuntu 14.04 LTS.

My example starts at this point in the quick start guide (but in python):

sql>SELECT type, COUNT(*) AS total

I loaded this snippet into the python3 interpreter:

from monetdb import sql

def p(c):

print('.rowcnt={}, .__offset={}, .rownumber={}'.format (

c.rowcount, c._Cursor__offset, c.rownumber))

print ('.__rows={}'.format (c._Cursor__rows))

db = sql.connect(database='voc', user='voc', password='voc')

cursor = db.cursor()

# Set the arraysize small so it traverses result sets,

# though it doesn't matter for the problem I'm seeing.

cursor.arraysize = 2

cursor.execute("SELECT type, COUNT(*) AS total FROM onboard_people GROUP BY type ORDER BY type;")

Then proceeded with this interactive session. Consecutive

fetchone()'s seem to work properly; it traverses to the second

result set. Where I get confused is when I .scroll():

>>> p(cursor)

.rowcnt=6, .__offset=0, .rownumber=0

.__rows=[('craftsmen', 2349), ('impotenten', 938)]

>>> cursor.fetchone()

('craftsmen', 2349)

>>> p(cursor)

.rowcnt=6, .__offset=0, .rownumber=1

.__rows=[('craftsmen', 2349), ('impotenten', 938)]

>>> cursor.fetchone()

('impotenten', 938)

>>> p(cursor)

.rowcnt=6, .__offset=0, .rownumber=2

.__rows=[('craftsmen', 2349), ('impotenten', 938)]

>>> cursor.fetchone()

('passengers', 2813)

>>> p(cursor)

.rowcnt=6, .__offset=2, .rownumber=3

.__rows=[('passengers', 2813), ('seafarers', 4468)]

# Here's where I scroll back to the beginning. The

# offset changes, but the rownumber doesn't.

>>> cursor.scroll (0, mode='absolute')

>>> p(cursor)

.rowcnt=6, .__offset=0, .rownumber=3

.__rows=[('craftsmen', 2349), ('impotenten', 938), ('passengers', 2813), ('seafarers', 4468), ('soldiers', 4177)]

# My expectation was that this would be ('craftsmen', 2349),

# but it continues as if I didn't scroll.

>>> cursor.fetchone()

('seafarers', 4468)

# I try to back to the last item with no luck, it instead

# marches forward to the next item as if I didn't scroll.

>>> cursor.scroll (-1, mode='relative')

>>> p(cursor)

.rowcnt=6, .__offset=3, .rownumber=4

.__rows=[('seafarers', 4468), ('soldiers', 4177), ('total', 2467)]

>>> cursor.fetchone()

('soldiers', 4177)

Am I using the .scroll() wrong? Is this a bug?

Thanks,

Chris