[Pdx-pm] Strange Random coredumps
mark at drapple.com
Thu Dec 19 14:35:09 CST 2002
I am having a very frustrating problem with a few Perl apps
I've written randomly dumping core, and I'm hoping someone can
point me in a direction to find the cause.
A little background as to what I'm doing:
I have a whole bunch of applications that I've written which run
as a CGI under Apache (1.3.26) on a FreeBSD (4.6.2-RELEASE-p4) machine.
There are actually 3 of these machines, one of which is running SSL.
All 3 machines are using Perl 5.005_03.
The applications are talking to a MS SQL server 2000 database (not by
my choice). I am using DBI:Sybase drivers to talk to the db. I know
that I could use ODBC drivers as well, but right now I'm using the
OK, now to the problem:
These applications get a fair amount of traffic each day (something along
the lines of 32,000 hits per day). One specific app takes about 25% of
that. Now, the app runs about 8000 times per day, and it will randomly
dump core anywhere from 0 up to 100 times per day, leaving no information in
Apache's error log as to what happened. The 0 days are good, but the other days
I end up taking heat from the client. I've tried adding debugging code into the
scripts to try and find where it dies, and I've had a reasonable amount of
success with this method, but the code is correct. The places where it is dying
don't seem to to form any kind of a pattern. Sometimes it dies trying to read
from the db, other times it will die while trying to generate some output. But
I know the code is correct and works. I've gone over it a zillion times, and it
runs perfectly over 7500 times per day. If I try to run it through the perl
debugger by hand, everything seems to work just fine, but with the fact that it
runs fine 98% of the time, that doesn't surprise me.
This is happening with several of the scripts. I was just using this one as
an example. I've found I can significantly reduce the number of times the
applications die if I simply put a:
print STDERR "foo\n";
in the script in a few different places. It makes no sense to me why adding
a few of those will cause a script to be significanlty more stable if I add
those. I realize I can just leave them in, but it feels like a bandaid, and
it doesn't eliminate the problem, it just reduces it.
Now some of these Perl scripts are reasonably large (the one I mention above
is 72kb with nearly 2000 lines), but the coredumps also happen on scripts with
only a couple hundred lines of code.
Does anyone have any advice or anything they can help me figure out with regards
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