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Intermittent error message when viewing problems

Intermittent error message when viewing problems

by Maria Nogin -
Number of replies: 2
Sometimes, when trying to view problems, users get an error message like the following. If the user reloads the page, the problem is shown correctly. This happens inconsistently, can happen with any problem, including those that have been used for years and we know there is nothing wrong with them. Restarting the server solves the problem temporarily, but within a couple of days this starts happening again.

Any ideas why this could be happening?

Error messages

Can't locate object method "getCopy" via package "Parser::Context" at line 988 of [PG]/macros/PGnumericevaluators.pl Died within main::NUM_CMP called at line 411 of [PG]/macros/PGnumericevaluators.pl from within main::num_cmp called at line 45 of [TMPL]/Library/Rochester/setTrig09Laws/srw6_1_53.pg
Error details

Problem2
ERROR caught by Translator while processing problem file:Library/Rochester/setTrig09Laws/srw6_1_53.pg
****************
Can't locate object method "getCopy" via package "Parser::Context" at line 988 of [PG]/macros/PGnumericevaluators.pl
Died within main::NUM_CMP called at line 411 of [PG]/macros/PGnumericevaluators.pl
from within main::num_cmp called at line 45 of [TMPL]/Library/Rochester/setTrig09Laws/srw6_1_53.pg

Request information
Time Wed Jan 27 14:34:14 2010
Method GET
URI /webwork2/Math5-Nogin/set_01/2/
HTTP Headers
Keep-Alive 300
Accept-Charset ISO-8859-1,utf-8;q=0.7,*;q=0.7
User-Agent Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.0.11) Gecko/2009061613 CentOS/3.0.11-2.el5.centos Firefox/3.0.11
Accept text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Connection keep-alive
Referer http://webwork2.math.csufresno.edu/webwork2/Math5-Nogin/set_01/1/?effectiveUser=mnogin&displayMode=images&key=qHJmiTg2iVxdpFd9IJCyBWqYPGg9NHhZ&user=mnogin
Accept-Encoding gzip,deflate
Cookie __qca=P0-2132759669-1251736433489; __utma=110011415.2469005800571971600.1251736434.1264451351.1264612528.50; __utmz=110011415.1264612528.50.50.utmcsr=zimmer.csufresno.edu|utmccn=(referral)|utmcmd=referral|utmcct=/~mnogin/; __unam=69a926a-123727f0344-37280b6e-5; cssln116HFR1-84915=6Rv7Lv3J5GdmnQprTM9pqw1TBhzjtPcK!-484220617; csuf_info=Maria Nogin~mnogin@csufresno.edu; csuf_auth=facstaf; https%3a%2f%2fmy.csufresno.edu%2fpsp%2fmfs%2fcsu%2ffresno%2frefresh=list:||||||||||||||||||||||||||||||||||||||||||||||||; PS_TOKEN=AAAAogECAwQAAQAAAAACvAAAAAAAAAAsAARTaGRyAgBOcwgAOAAuADEAMBThC0wHImLFgiDSdcQtXTiY8ihm4gAAAGIABVNkYXRhVnicLYpJCoAwEAQrKh49+I9ITCTRu8tNgl/xez7ONjhD10xBA7ep6gaDpno+9ow4AjNejLLQsnFydGR2LkkW10kFV8q2XCtP/z8oUQyFS9mkeF5zrwtr; ExpirePage=https://my.csufresno.edu/psp/mfs/; __utmc=110011415; cssln113HFR1-84915=rv3dLd1QvBCf1Z7D9WJ7pFCHjzgc2tTn!-168500861; cssln114HFR1-84915=LpvLLg1BlyXTJ0nhn9PzrxQhhfm8KqLT!1321201705; cssln137FFR1-84816=25fQLg0Yy5Rnch3tbHnZbj2pyrhfWk8D!-1469688737; cssln139FFR1-84816=HHg1Ld1fR7g9l751CvgpCHvkGynzgT7s!547896607; cssln133FFR1-84816=hR1nLGgLFbSZPkZ5qQPGlh9s2K6dtsGD!-733685691; cssln111HFR1-84915=ByksLGgQhJ69nNJkvTxC5PKvJMJq2jwT!565465510; cssln110HFR1-84915=nvCNLh1Q3sgcyWR2WdTG9yZJGQpkBznf!782771185; cssln112HFR1-84915=LWMDLFLCLPV6YRhtBMm46RcCKYrpvslQ!-551190033; frspplwebn2-csufresno-edu-443-PORTAL-PSJSESSIONID=Lg0Jnby8rQ4ppCfXMMsVCSYydwgnwV12!-1508339898
Accept-Language en-us,en;q=0.8,ru;q=0.5,fr;q=0.3
Host webwork2.math.csufresno.edu

or

Error detected while loading [PG]/macros/extraAnswerEvaluators.pl: Error
detected while loading [PG]/macros/MathObjects.pl: Error detected while
loading [PG]/macros/Parser.pl:
************************************************************ * This problem
requires the Parser.pm package, which doesn't * seem to be installed.
Please contact your WeBWorK system * administrator and ask him or her to
install it first.
************************************************************ Died within
main::compile_file called at line 308 of (eval 996) from within
main::loadMacros called at line 13 of [TMPL]/HWI/hw02p2.pg


In reply to Maria Nogin

Re: Intermittent error message when viewing problems

by Aleksey Nogin -

It looks as if somehow one of the apache server processes gets "corrupted" and then requests served by unaffected processes still work, while requests served by the corrupted process display an error. If this is indeed the case, it explains why restarting apache resolves the problem temporarily (until one of the server processes is corrupted" again).

We are using apache 2.2.3 (with prefork MPM) and mod_perl 2.0.4 under CentOS 5.4, Webwork rel-2-4-patches.

It would seem that the error first appears in the apache's error_log in the following form:

[Fri Jan 22 12:39:56 2010] [warn] [client 129.8.192.229] [/webwork2/Math75/HW_01/4/] Timeout after processing this problem for 60 seconds. Check for infinite loops in problem source., referer: http://webwork2.math.csufresno.edu/webwork2/Math75/HW_01/3/
[Fri Jan 22 12:39:56 2010] [warn] [client 71.195.187.195] [/webwork2/Math75/HW_01/3/] Timeout after processing this problem for 60 seconds. Check for infinite loops in problem source., referer: http://webwork2.math.csufresno.edu/webwork2/Math75/HW_01/3/?effectiveUser=mgemetti&displayMode=images&key=cLir9ToJP80Oo6jYPFV0yMbA7xXlQfwo&showOldAnswers=1&user=mgemetti
[Fri Jan 22 12:39:56 2010] [warn] [client 129.8.192.229] [/webwork2/Math75/HW_01/4/] Failed to evaluate module Parser: Timeout after processing this problem for 60 seconds. Check for infinite loops in problem source.\nBEGIN failed--compilation aborted at /opt/pg/lib/Parser/BOP/union.pm line 7.\nCompilation failed in require at /opt/pg/lib/Parser/BOP.pm line 347.\nBEGIN failed--compilation aborted at /opt/pg/lib/Parser/BOP.pm line 347.\nCompilation failed in require at /opt/pg/lib/Parser/Item.pm line 166.\nBEGIN failed--compilation aborted at /opt/pg/lib/Parser/Item.pm line 166.\nCompilation failed in require at /opt/pg/lib/Parser.pm line 792.\nBEGIN failed--compilation aborted at /opt/pg/lib/Parser.pm line 792.\nCompilation failed in require at (eval 969) line 1., referer: http://webwork2.math.csufresno.edu/webwork2/Math75/HW_01/3/
[Fri Jan 22 12:39:56 2010] [warn] [client 71.195.187.195] [/webwork2/Math75/HW_01/3/] Failed to evaluate module Parser: Timeout after processing this problem for 60 seconds. Check for infinite loops in problem source.\nBEGIN failed--compilation aborted at /opt/pg/lib/Parser/BOP/union.pm line 7.\nCompilation failed in require at /opt/pg/lib/Parser/BOP.pm line 347.\nBEGIN failed--compilation aborted at /opt/pg/lib/Parser/BOP.pm line 347.\nCompilation failed in require at /opt/pg/lib/Parser/Item.pm line 166.\nBEGIN failed--compilation aborted at /opt/pg/lib/Parser/Item.pm line 166.\nCompilation failed in require at /opt/pg/lib/Parser.pm line 792.\nBEGIN failed--compilation aborted at /opt/pg/lib/Parser.pm line 792.\nCompilation failed in require at (eval 1073) line 1., referer: http://webwork2.math.csufresno.edu/webwork2/Math75/HW_01/3/?effectiveUser=mgemetti&displayMode=images&key=cLir9ToJP80Oo6jYPFV0yMbA7xXlQfwo&showOldAnswers=1&user=mgemetti
[Fri Jan 22 12:39:56 2010] [warn] [client 71.195.187.195] [/webwork2/Math75/HW_01/3/] Failed to evaluate module Value: Timeout after processing this problem for 60 seconds. Check for infinite loops in problem source.\nBEGIN failed--compilation aborted at /opt/pg/lib/Parser/BOP/union.pm line 7.\nCompilation failed in require at /opt/pg/lib/Parser/BOP.pm line 347.\nBEGIN failed--compilation aborted at /opt/pg/lib/Parser/BOP.pm line 347.\nCompilation failed in require at /opt/pg/lib/Parser/Item.pm line 166.\nBEGIN failed--compilation aborted at /opt/pg/lib/Parser/Item.pm line 166.\nCompilation failed in require at /opt/pg/lib/Parser.pm line 792.\nBEGIN failed--compilation aborted at /opt/pg/lib/Parser.pm line 792.\nCompilation failed in require at (eval 1073) line 1., referer: http://webwork2.math.csufresno.edu/webwork2/Math75/HW_01/3/?effectiveUser=mgemetti&displayMode=images&key=cLir9ToJP80Oo6jYPFV0yMbA7xXlQfwo&showOldAnswers=1&user=mgemetti
[Fri Jan 22 12:39:56 2010] [warn] [client 129.8.192.229] [/webwork2/Math75/HW_01/4/] Failed to evaluate module Value: Timeout after processing this problem for 60 seconds. Check for infinite loops in problem source.\nBEGIN failed--compilation aborted at /opt/pg/lib/Parser/BOP/union.pm line 7.\nCompilation failed in require at /opt/pg/lib/Parser/BOP.pm line 347.\nBEGIN failed--compilation aborted at /opt/pg/lib/Parser/BOP.pm line 347.\nCompilation failed in require at /opt/pg/lib/Parser/Item.pm line 166.\nBEGIN failed--compilation aborted at /opt/pg/lib/Parser/Item.pm line 166.\nCompilation failed in require at /opt/pg/lib/Parser.pm line 792.\nBEGIN failed--compilation aborted at /opt/pg/lib/Parser.pm line 792.\nCompilation failed in require at (eval 969) line 1., referer: http://webwork2.math.csufresno.edu/webwork2/Math75/HW_01/3/
[Fri Jan 22 12:40:40 2010] [warn] [client 71.195.187.195] [/webwork2/Math75/HW_01/4/] Timeout after processing this problem for 60 seconds. Check for infinite loops in problem source.\n, referer: http://webwork2.math.csufresno.edu/webwork2/Math75/HW_01/3/
[Fri Jan 22 12:40:40 2010] [error] [client 71.195.187.195] [/webwork2/Math75/HW_01/4/] Timeout after processing this problem for 60 seconds. Check for infinite loops in problem source.\n\n * in WeBWorK::PG::Local::new called at line 52 of /opt/webwork2/lib/WeBWorK/PG.pm\n * in WeBWorK::PG::new called at line 598 of /opt/webwork2/lib/WeBWorK/ContentGenerator/Problem.pm\n * in WeBWorK::ContentGenerator::Problem::pre_header_initialize called at line 176 of /opt/webwork2/lib/WeBWorK/ContentGenerator.pm\n * in WeBWorK::ContentGenerator::go called at line 353 of /opt/webwork2/lib/WeBWorK.pm, referer: http://webwork2.math.csufresno.edu/webwork2/Math75/HW_01/3/
[Fri Jan 22 12:40:42 2010] [warn] [client 71.195.187.195] [/webwork2/Math75/HW_01/3/] Failed to evaluate module Parser::Legacy: Can't call method "copy" on an undefined value at /opt/pg/lib/Parser/Legacy/LimitedNumeric.pm line 81.\nCompilation failed in require at /opt/pg/lib/Parser/Legacy.pm line 6.\nBEGIN failed--compilation aborted at /opt/pg/lib/Parser/Legacy.pm line 6.\nCompilation failed in require at (eval 1074) line 1., referer: http://webwork2.math.csufresno.edu/webwork2/Math75/HW_01/3/?effectiveUser=mgemetti&displayMode=images&key=cLir9ToJP80Oo6jYPFV0yMbA7xXlQfwo&showOldAnswers=1&user=mgemetti
[Fri Jan 22 12:40:43 2010] [warn] [client 129.8.192.229] [/webwork2/Math75/HW_01/4/] Failed to evaluate module Parser::Legacy: Can't call method "copy" on an undefined value at /opt/pg/lib/Parser/Legacy/LimitedNumeric.pm line 81.\nCompilation failed in require at /opt/pg/lib/Parser/Legacy.pm line 6.\nBEGIN failed--compilation aborted at /opt/pg/lib/Parser/Legacy.pm line 6.\nCompilation failed in require at (eval 970) line 1., referer: http://webwork2.math.csufresno.edu/webwork2/Math75/HW_01/3/
[Fri Jan 22 12:41:46 2010] [warn] [client 71.195.187.195] [/webwork2/Math75/HW_01/4/] Timeout after processing this problem for 60 seconds. Check for infinite loops in problem source., referer: http://webwork2.math.csufresno.edu/webwork2/Math75/HW_01/3/

with a lot more similar messages afterwards...

In reply to Aleksey Nogin

Re: Intermittent error message when viewing problems

by Davide Cervone -
Your problem does seem a bit unusual. The line in pg/lib/Parser/BOP/union.pm that is indicated as the error is "use strict", which should not cause an infinite loop. But that line is mainly for assistance in debugging, so you can safely comment it out. Try that and see if that helps. The other messages (about the copy method) are probably because the child that timed out is getting used for additional requests, and thinks that the parser code is set up while actually it isn't.

Davide