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David Geller
dg at sponsera.com
Sat Jan 24 17:14:45 EST 2004
All:
Awhile ago I posted an issue under "mod_python and mysql - wierd
problem!' 1/8/2004
I was having similar problems to those described here:
1. python program with sql queries worked fine in "console" mode
2. under mod_python, when I called "c.execute()", httpd would get a
"segmentation fault" (this was apparent in the httpd error log)
3. sometimes, instead, I would get weird, inconsistant errors, like
Petros decribes.
Paul Querna actually hinted at what was wrong - but it took me awhile to
find it (what was especially strange, and still unexplained, is why
things worked fine under mod_python on my redhat8 machine, but then
failed on the redhat9 server).
Explanation(?):
In my httpd.conf I was loading two DSO modules: mod_python and php4. It
turns out, when I removed the reference to php4, the mod_python worked
perfectly. Now, why was this? Well, I went back to the php4 module, and
checked out "configure" - if you know anything about php, it was being
configured with the "--with-mysql" flag, which tells it to use an
"internal" version of mysql libs. Apparently, this is fine - as long as
*no other modules use mysql* (the php configure tells you this at the
end). If they do, you should specify the actual mysql library directory.
Well, mod_python was basically another module using mysql. Duuuuh!
(well, not so obvious to me, really). When I specified the actual mysql
library to php configure, and recompiled and reinstalled the PHP, I
could have LoadModules for both php and mod_python and both *appear* to
work.
Not completely sure why this is, but it seems to have solved the problem.
David
Petros Keshishian wrote:
>Ross:
>
>I had the same problem in mod_python with MySQL:
>Namely the script was working from python shell, but
>not in mod_python. I discovered that when I query only
>one column , e.g.
>C.execute('select id from cities where id=17;')
>than it worked in mod_python as well, but when I try
>for more that one column it dies. Unfortunatly I could
>not find a solution and since my database is very
>small I wrote a script that queries the database for
>each column separately and then combines and returns
>the result. This is not really a solution because it
>does not address the problem and can slow down your
>program significantly if your database is large.
>
>Try to see whether your script works when you query
>only one column. I am very intersted in the solution
>of this problem.
>
>-Petros
>
>
>= = = Original message = = =
>
>Hello,
>
>I am working on porting some scripts over to
>mod_python, but my scripts
>die when I attempt to execute a MySQL query.
>
>Here is a demonstration of the problem:
>http://localfeeds.com/near/display-rss.app
>
>In mozilla, it loads a blank page, on Safari, I get a
>"page returned no
>data" error.
>
>The code in display-rss.py is:
>-------------------------------
>DB = "db"
>USER = "user"
>PASS = "password"
>
>import MySQLdb
>
>def index(req):
>
> DB_CONN = MySQLdb.connect(db=DB, user=USER,
>passwd=PASS)
> C=DB_CONN.cursor()
> C.execute('select * from cities where id=17;')
> return "Something"
>-------------------------------
>
>I have also tried using the code from :
>http://www.modpython.org/FAQ/faqw.py?req=all#3.3
>
>If I comment out the 'execute' statement, it works
>fine, the page that
>comes back displays the word "Something:", as
>expected.
>
>I am using Apache/2.0.48
>Python 2.3.3
>mod_python 3.0.4
>on FreeBSD 4.9
>
>My Apache configuration is:
>AddHandler python-program .app
>PythonHandler mod_python.publisher
>PythonAutoReload On
>PythonDebug On
>
>I suspect this will be related to the Apache/FreeBSD
>threading can of
>worms... but I'm hoping there is another answer. If
>anyone has a spare
>clue to offer, I'd really appreciate it.
>
>Thanks!,
>
>-Ross
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--
David Geller
Sponsera, LLC
dg at sponsera.com
www.sponsera.com
Phone: 703.532.6812
Fax: 703.532.6058
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