[Zope] Zope hangs and Python eats all memory

[Peter Bengtsson]

Hi Nico,
I've also struggled with Easysoft's OOB (Odbc-Odbc Bridge) and with dire 
results. The main problem we had wasn't seg faults but that it got hung 
up and stopped responding probably due to abandonned closed connection 
sockets.
On a completely different customer I managed to get a Zope 2.8.8 
recently working with egenix mxODBC Zope DA to a MS SQL Server using 
FreeTDS and that worked a lot better. I was happy to this time avoid the 
extra headache of Easysoft OOB.
NB! I couldn't get it to work with iODBC. It only worked with unixODBC.

On another project where we used Easysoft I did some rough profiling on 
the speed difference between unixODBC and iODBC and found no distinct 
difference so if you, like me, can only get unixODBC to talk to FreeTDS 
then don't worry about iODBC.

Nico Grubert wrote:
>> I am running Zope 2.9.6. on a 64-Bit Suse Linux 10.1 machine (9 Gbyte 
>> of RAM) with Python 2.4.3. installed.
>> From time to time, Zope hangs and I cannot access it anymore. I tried 
>> to use the "Zope DeadlockDebugger" but if my Zope hangs I cannot call 
>> the URL "http://myzopesite:8080/manage_debug_threads?secret_password" 
>> to let Zope DeadlockDebugger show any useful information. Zope does 
>> not response.
>> If Zope hangs, the python process eats all the memory and the machine 
>> starts to swap.
> 
> I think I have found the reason for this problem:
> 
>   The problem comes from a python segmentation fault caused by either
>   "egenix mxODBCDA" database adapter or "Easysoft ODBC-ODBC Bridge".
> 
> 
> Here is a short description about the problem:
> ---------------------------------------------------------------------------
>  From a linux machine I am accessing a remote windows 2003 server machine
> to query a Filemaker Pro database. I have "Easysoft ODBC-ODBC Server 
> 2.0.6 for Windows" installed in my windows machine.
> 
> On my linux machine I use the "unixODBC" (Easysoft ODBC-ODBC Client 
> 2.0.6 for Linux) driver and the Zope product "mxODBCZopeDA" to query the 
> Filemaker Database.
> 
> After I started Zope and make a few SQL queries, the Zope server shuts
> down with a "Segmentation fault".
> At the same time there is a log entry on my linux machine in
> /var/log/messages that reads:
> Jan 23 10:43:09 smut kernel: python[6231]: segfault at 00000000ffffffff
> rip 000000000043c0d7 rsp 00000000417f6ad0 error 4
> 
>  From time to time Zope even hangs and eats all memory until the whole 
> machine hangs completely. Every time this happen, the last entry in 
> <zope_instance>/log/trace.log is a request to a Zope Page Template where 
> a ZSQL method is called to query the ODBC source (Filemaker). At the 
> same time there is a "python segmentation fault" log entry on my linux 
> machine in /var/log/messages.
> 
> One of the developers of the "mxODBCZopeDA" product told me the error is
> definitely coming from the ODBC-ODBC bridge.
> 
> However, I can query the Filemaker database and get nice results but
> after a while my Zope server shuts down with the error messages above. I
> don't do any SQL INSERT or SQL UPDATE. I just do some SQL
> "SELECT...FROM...WHERE..." queries.
> 
> My setup:
>   + 64-Bit Suse Linux 10.1 Professional
>   + unixODBC & unixODBC-devel 2.2.11
>   + Easysoft ODBC-ODBC Client 2.0.6 for Linux
>   + Easysoft ODBC-ODBC Server 2.0.6 for Windows
>   + ODBC Source: Filemaker Pro 8 Advanced Server on a Windows2003 Server
>   + Python 2.4.3.
>   + Zope 2.9.6.
>   + mxODBCZopeDA 1.0.10
> 
> 
> On a 32-Bit Suse 9.2 with unixODBC & unixODBC-devel 2.2.9, Python 2.5.3. 
> and Zope 2.8.8. installed this error never occured. The segmentation 
> fault only occurs on my 64 bit OS as described above.
> 
> I'm waiting for an answer from the Easysoft ODBC-ODBC support but I'm 
> gonna try to update Python 2.4.3. to 2.4.5. in order to see if it may 
> solve the problem.
> 
> 
> Thanks to Dieter, Suresh and Paul.
> 
> Nico
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-- 
Peter Bengtsson,
work www.fry-it.com
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