Re: [cx-oracle-users] ORA-03127

[Mike E. <Mik...@eu...>]

I've also seen this issue. The problem occurs when Django reads from the field SESSION_DATA, type NCLOB, in table DJANGO_SESSION. In cx_Oracle 5.1 the function ExternalLobVar_InternalRead() calls OCILobRead() with csid set to 0, whereas in 5.0.4 csid was set to OCI_UTF16ID when reading NCLOB fields. This causes OCILobRead() to fail but it is not reported at the time, leaving the cursor in an incomplete state and eventually an exception is thrown when the connection is closed.

The error doesn't occur when I connect to an Oracle 10 database with NLS_NCHAR_CHARACTERSET of  "AL16UTF16" but it does occur with an Oracle 11 database with NLS_NCHAR_CHARACTERSET set to "UTF8".

Hope this helps! I put together a small patch (attached) that makes the problem go away but I'm not sure it's the correct fix.

Regards, Mike.

> Hi,
>
> I looked at it. The error is referring to the fact that the operations
> on the connection are not yet complete. Since it is taking place on a
> close() you can simply NOT do the close and allow it to close on its
> own when it goes out of scope. There was a change made to
> cursor.close() which may affect this but it seems unlikely. It would
> be helpful if you can provide a script that demonstrates the problem
> so that I can figure out why this might be happening. Thanks. I
> certainly have never run into this myself and I am using Django with
> cx_Oracle quite heavily.
>
> Anthony
>
> 2011/8/25 Sławek Ehlert <slafs.e@...>:
> > Hi there!
> >
> > Can You look at
> >
> > https://groups.google.com/d/topic/django-users/P9brNKIFwgI/discussion
> >
> > Recently I saw a similar problem when using cx_Oracle 5.1 when switching
> > Django 1.3 (Python 2.6) to another Oracle database (after syncing it) on
> > 64bit platform.
> >
> > Downgrading to 5.0.4 "solved" the problem.
> >
> > Regards
> >
> > Sławek
> >
> >
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>