Re: [cx-oracle-users] Oracle crash with CLOB and threading

[Anthony T. <ant...@gm...>]

I finally had a chance to try your program and did not run into any
difficulties at all. The error you report is an Oracle crash and so is
likely due to your particular Oracle software configuration. My own
(which worked) was:

Python 2.3 and Python 2.5
Oracle Standard 9.2.0.5 (both server and client)
Linux - Fedora Core 6 32-bit (both server and client)

I would suggest scanning the Oracle bug database for the error you
encountered. During my own traversals of that databse I have seen a
number of problems related to CLOBs and segfaults like you indicated.
I know that patchset 9.2.0.8 has been released -- its possible your
issue has been addressed there.

I unfortunately do not have access to an installation of the
Enterprise edition running 64-bit anything -- so I can't help you in
your specific configuration. Perhaps someone else on the list knows
about this issue or can test it in an environment more similar to the
poster's?

On 1/26/07, Torsten Prange <Tor...@to...> wrote:
> Hello,
>
> my collegue sent this mail today but has not subscribed to the mailing list
> probably.
>
>
> Mail from Rog...@to...:
>
> Hi,
>
> I am having some problems with cx_Oracle, threads and clob's and am looking for
> some guidance.
>
> For the record:
>         The system is "SunOS tmxd01 5.9 Generic_112233-10 sun4u sparc"
>         cx_Oracle version is cx_Oracle-4.2.1
>         Oracle version is: Oracle9i Enterprise Edition Release 9.2.0.7.0 - 64bit
> Production
>         Python 2.2.2 (#10, Mar 19 2003, 14:11:47)
>
> When manipulating clobs in the database I occasionally got an Oracle error:
>
>         OCI-21500: internal error code, arguments: [nnnnn], [], [], [], [], [], [], []
>
> I have a test program that can now reproduce the problem at will, by repeatedly
> inserting, selecting and deleting
> on a table containing a clob from several threads. The error output looks like
> this:
>
> OCI-21500: internal error code, arguments: [17099], [], [], [], [], [], [], []
> Errors in file :
> OCI-21500: internal error code, arguments: [17099], [], [], [], [], [], [], []
>
> ----- Call Stack Trace -----
> NOTE: <PLT>+offset is used to represent that the
>       function being called is offset bytes from
>       the _PROCEDURE_LINKAGE_TABLE_.
> calling              call     entry                argument values in hex
> location             type     point                (? means dubious value)
> -------------------- -------- -------------------- ----------------------------
> Segmentation Fault(coredump)
>
> Note that Oracle coredumps trying to print the stack trace.
>
> Change the data type from clob to varchar, and the problem disappears.
>
> I can also get rid of the problem by opening connections discreetly instead of
> using the
> cx_Oracle.SessionPool object, which surprised me rather.
>
> I am currently looking at the SessionPool, and clob object code in cx_Oracle
> (Sadly, I am no expert with Python extensions),  maybe there is some issue with
> reference counts?
>
> Any advice would be gratefully accepted.....
>
> The test program and sql script is attached to this e-mail (thread_test_clob.py
> and tables_clob.sql)
>
> Thanks in advance...
>
> Roger
>
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