[pypy-dev] Running pysqlite on pypy

[Antonio Cuni]

Hi Gerhard, hi all,

in the last days, we have been trying to run django on pypy, using the 
ctypes based implementation of pysqlite.

In doing this, we encountered a problem; we have exchanged a bit of 
private mails, so I try to sum up here:

This snippet explodes when run with pysqlite-ctypes, either on cpython 
or pypy-c:

 >>>> from pysqlite2.dbapi2 import connect
 >>>> db = connect(':memory:')
 >>>> db.execute('BEGIN IMMEDIATE TRANSACTION')
<pysqlite2.dbapi2.Cursor object at 0xb7dc4f6c>
 >>>> db.execute('COMMIT')

Traceback (most recent call last):
    File "<stdin>", line 1, in ?
    File "/home/exarkun/Scratch/Source/pysqlite3/pysqlite2/dbapi2.py",
  line 315, in execute
      return cur.execute(*args)
    File "/home/exarkun/Scratch/Source/pysqlite3/pysqlite2/dbapi2.py",
  line 483, in execute
      raise self.connection._get_exception()
  pysqlite2.dbapi2.OperationalError: SQL logic error or missing database


The very same thing happens on python 2.4 + pysqlite2 (non-ctypes version):

 >>> from pysqlite2.dbapi2 import connect
 >>> db = connect(':memory:')
 >>> db.execute('BEGIN IMMEDIATE TRANSACTION')
<pysqlite2.dbapi2.Cursor object at 0xb7cb0860>
 >>> db.execute('COMMIT')
Traceback (most recent call last):
   File "<stdin>", line 1, in ?
pysqlite2.dbapi2.OperationalError: cannot commit - no transaction is active


However, it works perfectly on cpython 2.5 + sqlite3:

 >>> from sqlite3.dbapi2 import connect
 >>> db = connect(':memory:')
 >>> db.execute('BEGIN IMMEDIATE')
<sqlite3.Cursor object at 0xf7cff050>
 >>> db.execute('COMMIT')
<sqlite3.Cursor object at 0xf7cff020>


Samuele pointed out that maybe it's just a difference between pysqlite2 
and pysqlite3; after more digging, he changed pysqlite-ctypes to print 
every SQL statement before sending it to sqlite; what he got is this:

Python 2.5.1 (r251:54863, Jan 17 2008, 19:35:17)
[GCC 4.0.1 (Apple Inc. build 5465)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
 >>> from pysqlite2 import dbapi2
 >>> db = dbapi2.connect(':memory:')
 >>> db.execute('BEGIN IMMEDIATE TRANSACTION')
BEGIN IMMEDIATE TRANSACTION
<pysqlite2.dbapi2.Cursor object at 0x55e90>
 >>> db.execute('COMMIT')
COMMIT
COMMIT
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "pysqlite2/dbapi2.py", line 318, in execute
    return cur.execute(*args)
  File "pysqlite2/dbapi2.py", line 489, in execute
    raise self.connection._get_exception()
pysqlite2.dbapi2.OperationalError: SQL logic error or missing database

The double COMMIT is probably causing the problem; not sure if it's a 
bug in pysqlite-ctypes or an expected behavior.


Gerhard, what do you think about all of this? What's the best way to solve?

ciao,
Anto