Troubleshooting

Subtle issues with CMS can arise from old versions of libraries or supporting software. Please ensure you are running the minimum versions of each dependency (described in the README).

Here are some known symptoms and their causes.

Symptom. Error message "Cannot determine OID of function lo_create" Possible cause. Your database must be at least PostgreSQL 8.x to support large objects used by CMS.

Symptom. Exception containing "ranking_view is None" Possible cause. You need to start ScoringService

Symptom. Message from ContestWebServer such as:

WARNING:root:Invalid cookie signature KFZzdW5kdWRlCnAwCkkxMzI5MzQzNzIwCnRw...

Possible cause. The contest secret key (defined in cms.conf) may have been changed and users' browsers are still attempting to use cookies signed with the old key. If this is the case, the problem should correct itself and won't be seen by users.

Symptom. Ranking Web Server misbehaving Possible cause. Ensure you are running Tornado 2.0 or higher. (see issue #2)

Symptom. Ranking Web Server displays wrong data, or too much data. Possible cause. RWS is designed to handle groups of contests. If you want to delete the previous data, run it with the -d option.

Symptom. The freopen test fails. Possible cause. Add the dup3 syscall to the allowed list.

Symptom. Importing a contest with ContestImport fails. Possible cause. The contest was exported with a previous version of CMS. Wait for us to provide update scripts for exports, or contact us for the fast solution.

Symptom. ResourceService keeps restarting its services. Possible cause. A reason for this could be that the "process_cmdline" in the configuration isn't suited to your system. To find the one that suits you, you can run a service by hand (for example cmsLogService), then run ps aux and search for a process that looks like /usr/bin/python /usr/local/bin/cmsLogService. The "process_cmdline" corresponding to this would be ["/usr/bin/python", "/usr/local/bin/cms%s", "%d"]. This value is the default one and should work well on most Ubuntu systems, but for example on some Gentoo systems you may need to use ["/usr/bin/python2.7", "/usr/bin/cms%s", "%d"].