David,
Thanks for your suggestions, but none of these errors would be transient.
Just did a quick count. Most of the errors (roughly well over 95%)
occur on GET operations. They tend to come in bursts, which is why I
suspect some resource problem.
The error logs aren't very helpful in this matter either. They suggest
database connection failures (which is why I increased the listener
queue), but I don't understand how these could be resolved without
intervention:
DBI->connect failed: ORA-12545: Connect failed because target host or
object doe
s not exist (DBD ERROR: OCIServerAttach) at
/usr/local/blackboard/perl/lib/site_
perl/5.005/Apache/DBI.pm line 138
DBI->connect failed: ORA-12154: TNS:could not resolve service name (DBD
ERROR: O
CIServerAttach) at
/usr/local/blackboard/perl/lib/site_perl/5.005/Apache/DBI.pm
line 138
[Mon Dec 2 16:03:02 2002] [error] DATABASE CONNECTION FAILURE
DBI->connect fail
ed: ORA-12154: TNS:could not resolve service name (DBD ERROR:
OCIServerAttach) a
t /usr/local/blackboard/perl/lib/site_perl/5.005/CI.pm line 131
ORACLE_HOME environment variable not set!
[Mon Dec 2 16:03:04 2002] [error] DATABASE CONNECTION FAILURE
DBI->connect fail
ed: ORA-12154: TNS:could not resolve service name (DBD ERROR:
OCIServerAttach) a
t /usr/local/blackboard/perl/lib/site_perl/5.005/CI.pm line 131
Kind regards,
Herta
David Pattern wrote:
>Unfortunately, a 500 error covers a multitude of sins - basically something
>went wrong whilst the server was trying to fulfil the request from the web
>browser. It could be a fatal error in one of the scripts, or an incorrect
>file permission, a HTTP file upload failing, the initial "shebang" line in a
>CGI script missing or pointing to the wrong location... and probably many
>other things too.
>
>You can sometimes get more of an idea by looking in the Apache error.log
>file (usually "/var/log/httpd/error.log" or "/var/log/apache/error.log").
>
>regards
>Dave Pattern
>INHALE/INFORMS Project
>
>
>-----Original Message-----
>From: Herta Van den Eynde [mailto:[log in to unmask]]
>Sent: 02 December 2002 12:00
>To: [log in to unmask]
>Subject: 500 - Internal Server Error
>
>
>Environment: linux + oracle + bb 5.5.1 level3
>
>Does anyone know what causes the "500 - Internal Server Error" messages in
>blackboard? They're usually short lived, so if the user waits a few seconds
>and hits the reload button, he usually is OK again.
>(On linux you can count the errors by means of the following command:
># grep " 500 " /usr/local/blackboard/httpd/logs/access_log | wc -l
>We're getting anywhere between 400 to 900 a day.)
>
>I've browsed Blackboard's support pages. They are aware of the problem, but
>don't seem to have a clue as to what causes it.
>
>Initially I thought it might be a resource problem, so I bumped up Apache's
>MaxClients in httpd.conf, and increased the Oracle listener queue. All to
>no avail. I've checked bbuser process limits, system wide maximum number of
>tasks, monitored the system, but there are no apparant bottlenecks.
>
>Any ideas?
>
>Herta
>
>
--
******************************************************
Herta Van den Eynde
Toledo system management
K.U.Leuven - Ludit
W.de Croylaan 52A
B-3001 Heverlee
Belgium
tel: +32 (0)16 322 166
fax: +32 (0)16 322 999
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"For something fulfilled this hour, loved or endured."
(W.H. Auden)
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