alright...well in this test program , i dont see the "threading=True"
keyword sent to create_engine, the patch i checked in to 0.1 still
has "threading" defaulting to False.
also id try running this with "strace", "truss", etc. to perhaps see
where the segfault is occurring more closely.
and, using a sqlite connection has no issue ?
you also might try making a more primitive program that just uses
sqlalchemy.pool to get a pooled connection, i.e. not use the SQL
construction stuff. *or* dont use SA at all, use cx_Oracle directly
and just put a connection in each thread. the amount of SA code
being used here is very low.
also whats the threshhold at which this fails ? 50 concurrent
threads is pretty high? is memory staying constant ?
On May 15, 2006, at 5:18 PM, Florian Boesch wrote:
For the life of me I couldn't figure that one out. Though I got a
concise test
programm for it. I applied your patch Michael, and it helps with
the strange
errors on select. But still eventually the programm Segmentation
Fauls, no
message and nothing.
* Threading myself without cherrypy I couldn't reproduce the problem
* Stressing cherrypy alone without sqlalchemy I couldn't reproduce
the problem
* Stressing both in concert only shows the behavior.
So atached you find a test programm that is both a small cherrypy
app (cherrypy
2.1) and a little web stress tester.
Cheers,
Florian
Quoting Michael Bayer <[EMAIL PROTECTED]>:
just did a google for "cx_oracle threadsafe" and came up with this:
http://mail.python.org/pipermail/db-sig/2004-January/003897.html
but then there also seems to be a more improved way as of 4.0.1 which
is this:
http://starship.python.net/crew/atuining/cx_Oracle/html/module.html
So, threading support is false by default since it has a 10-15%
performance hit. would we like this flag to be on by default ?
heres a patch to apply to oracle.py in the 0.1 series, which will add
'threaded' as a keyword parameter to oracle's create_engine. try
setting it to true and see if that fixes your problem:
--- lib/sqlalchemy/databases/oracle.py (revision 1407)
+++ lib/sqlalchemy/databases/oracle.py (working copy)
@@ -106,9 +106,10 @@
]}
class OracleSQLEngine(ansisql.ANSISQLEngine):
- def __init__(self, opts, use_ansi = True, module = None,
**params):
+ def __init__(self, opts, use_ansi = True, module = None,
threaded=False, **params):
self._use_ansi = use_ansi
self.opts = self._translate_connect_args((None, 'dsn',
'user', 'password'), opts)
+ self.opts['threaded'] = threaded
if module is None:
self.module = cx_Oracle
else:
On May 15, 2006, at 10:13 AM, Florian Boesch wrote:
Hi,
Selecting from multiple threads with thread-count > 10 my app:
* crashes without any error message
* starts spweing out
cx_Oracle.DatabaseError: Error while trying to retrieve text for
error ORA-12520
* crashes with:
*** glibc detected *** double free or corruption (fasttop):
0x3eeff0b8 ***
* all of the above
With 10 threads it seems to run rock-solid. With 11 it gets the
errors
occasionally. with 50 it gets them quite reliably, with 200 you
could
practically bet on the errors to happen. Though they don't show up
regularly,
mostly they happen fast or not for a long time.
I get the error as well on Linux as on Windows.
Any ideas what I can do (other then limiting my web-server to 10
threads)?
Example Atached
Cheers,
Florian
<segmentation_fault.py>
<segmentation_fault.py>
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