Psycopg psycopg

Comments and changes to this ticket

• 

  Daniele Varrazzo February 22nd, 2012 @ 01:52 PM

  Hi Mariano,

  Can't reproduce what you say: can you provide an example? I've tried with regular cursors as well with DictCursor and NamedTupleCursor:

  In [1]: import psycopg2
  
  In [2]: cnn = psycopg2.connect('')
  
  In [3]: cur = cnn.cursor()
  
  In [4]: cur.execute('select * from generate_series(1,10)')
  
  In [5]: cur.rownumber, cur.rowcount
  Out[5]: (0, 10)
  
  In [7]: cur.fetchone()
  Out[7]: (1,)
  
  In [8]: cur.rownumber, cur.rowcount
  Out[8]: (1, 10)
  
  In [9]: cur.fetchmany(3)
  Out[9]: [(2,), (3,), (4,)]
  
  In [10]: cur.rownumber, cur.rowcount
  Out[10]: (4, 10)
  
  In [11]: import psycopg2.extras
  
  In [12]: cur = cnn.cursor(cursor_factory=psycopg2.extras.NamedTupleCursor)
  
  In [13]: cur.rownumber, cur.rowcount
  Out[13]: (0, -1)
  
  In [14]: cur.execute('select * from generate_series(1,10)')
  
  In [15]: cur.rownumber, cur.rowcount
  Out[15]: (0, 10)
  
  In [16]: cur.fetchone()
  Out[16]: Record(generate_series=1)
  
  In [17]: cur.rownumber, cur.rowcount
  Out[17]: (1, 10)
  
  In [18]: cur.fetchmany(3)
  Out[18]: 
  [Record(generate_series=2),
   Record(generate_series=3),
   Record(generate_series=4)]
  
  In [19]: cur.rownumber, cur.rowcount
  Out[19]: (4, 10)
  
  In [20]: cur = cnn.cursor(cursor_factory=psycopg2.extras.DictCursor)
  
  In [21]: cur.execute('select * from generate_series(1,10)')
  
  In [22]: cur.rownumber, cur.rowcount
  Out[22]: (0, 10)
  
  In [23]: cur.fetchone()
  Out[23]: [1]
  
  In [24]: cur.rownumber, cur.rowcount
  Out[24]: (1, 10)
  
  In [25]: cur.fetchmany(3)
  Out[25]: [[2], [3], [4]]
  
  In [26]: cur.rownumber, cur.rowcount
  Out[26]: (4, 10)
  
  In [27]: psycopg2.__version__
  Out[27]: '2.4.4 (dt dec pq3 ext)'
  

  Please provide an example of the problem, thanks.

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  Mariano February 23rd, 2012 @ 11:41 AM

  Hi again Daniele!

  This is the code I've tried.

  import psycopg2, psycopg2.extras
  cnn = psycopg2.extras.DictConnection("user='postgres'")
  cur = cnn.cursor()
  cur.execute('select * from generate_series(1,10)')
  for i in cur:

      print (cur.rownumber, cur.rowcount)
  

  ---

  If I execute it with 2.4.2, with python2 and python3, I get:
  (1, 10) (2, 10) (3, 10) (4, 10) (5, 10) (6, 10) (7, 10) (8, 10) (9, 10) (10, 10)

  If I execute it with 2.4.4, with python2 and python3, I get the error:
  (10, 10) (10, 10) (10, 10) (10, 10) (10, 10) (10, 10) (10, 10) (10, 10) (10, 10) (10, 10)

  Thank you

• 

  Daniele Varrazzo February 23rd, 2012 @ 12:01 PM

  • State changed from “new” to “open”

  I see: It's probably a regression introduced with this change, to make itersize work as expected.

  https://github.com/dvarrazzo/psycopg/commit/8473209d240bad964630b9b...

  Will see this evening how to fix it. The problem is shared by several cursor subclasses.

• 

  Daniele Varrazzo February 23rd, 2012 @ 11:18 PM

  • State changed from “open” to “resolved”

  Fixed in my dev branch.

  rownumber is still broken for named cursors though. This would be an entirely different correction, and they have been broken forever, so I'm not in hurry to fix them.