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Jim Gallacher
jpg at jgassociates.ca
Fri Jan 20 19:21:40 EST 2006
Sean Jamieson wrote: > Jim Gallacher wrote: > >> Sean Jamieson wrote: >> >>> Jim Gallacher wrote: >>> >>>> Sean Jamieson wrote: >>>> >>>>> apache2/error.log is showing more than a few segfaults... >>>> >>>> >>>> >>>> >>>> >>>> Segfaults! Now we are getting somewhere. There are likely some >>>> subtle differences in the python libraries and apache modules being >>>> used on the server and laptop. The usual culprits libexpat and mysql >>>> clientlib used by php, but other libs can cause problems too. These >>>> links may help you sort it out: >>>> >>>> http://www.dscpl.com.au/articles/modpython-006.html >>>> http://www.modpython.org/FAQ/faqw.py?req=all#2.13 >>>> >>>> Jim >>> >>> >>> >>> >>> I made the segfault stop, but I'm not sure why exactly... >>> to start at the beginning, there was another weirdness going on with >>> mod_python, that was not a big deal, and I assumed to be "just how it >>> works": >>> if my project is in a subdirectory under the document root, I'd have >>> to do my imports from the document root. >>> i.e. >>> DocumentRoot /var/www >>> Project Root /var/www/project >>> /var/www/project/index.py: >>> import project.package.module >>> this seems strange as I sholud only have to do >>> import package.module >>> with out having to include the directory that index.py actually >>> resides in... >>> Now, keeping that in mind, I uploaded the source to my dev server, >>> and to stop the segfaults I simply changes the imports to the second >>> (expected) from, excluding the 'project' directory from the import path. >>> *inhale* >>> >>> I don't know if that really fixed anything, or just caused some other >>> error to be happening that prevents the whatever code is segfaulting >>> from actually being run. >>> But, in either case, I get no error or output or log messages telling >>> me useful. All I do get is: >>> [notice] mod_python: (Re)importing module 'index' with path set to >>> '['/.....']' >>> and once in a while this is above it: >>> [notice] mod_python: (Re)importing module 'mod_python.publisher' >> >> >> >> Publisher has it's own import and reload mechanism. Using a python >> import statement for modules that may also be imported by >> mod_python.publisher may give interesting results. If your >> project.package.module does not contain functions that are published >> directly I would suggest moving it completely out of your DocumentRoot >> and put it somewhere on your python path, or use the apache PythonPath >> directive to add it to the path. eg. >> >> PythonPath "['/home/sean/website-modules/',] + sys.path" >> >> This import issue is not likely related to the segfaults however. >> >>> OTOH, that link you gave me about PHP's mysql libs conflicting with >>> mod_python and MySQLdb might be the very thing causing problems, but >>> BOTH my laptop and my dev server have php4.4.0 installed... and both >>> are from ubuntu's apt (infact, I haven't custom compiled anything on >>> either machine since I built them, all are package managed, and >>> recently updated) >> >> >> >> A few weeks ago I ran apt-get update for python related packages on >> one of my debian machines and immediately started getting apache >> segfaults. Turned out that php4-mysql was using libmysqlclient.so.10 >> and the new python was using libmysqlclient.so.12. Updating php4-mysql >> brought the 2 libs in line and the segfault went away. I don't think >> this sort of problem is easily solved by any package manager, so it's >> something to keep in mind when doing updates. >> >> Jim >> >> PS. It's a good idea to keep discussions on list. > > > OK, so after many hours of hair pulling, I finally figured out the > problem *is* with PHP's mysql library. > > Disabling PHP entirely allowed my python code, which uses MySQLdb, to work. > > Tomorrow I'm going to figure out how to make PHP and MySQLdb play > nicely, taking your comment above into consideration. FYI, here's a starting point: $ ldd /usr/lib/python2.4/site-packages/_mysql.so |grep mysql $ ldd /usr/lib/php4/20050606/mysql.so |grep mysql (The php mysql.so file may be in a different location on Ubuntu). Jim
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