Forum OpenACS Q&A: Re: Re: Assessment - urgent

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Posted by Peter Alberer on
Have a look at this thread here: http://archives.postgresql.org/pgsql-general/2004-09/msg00442.php
The problem seems to come from a combination of a postgres "problem" with the intensive use of revisions in the assessment package.
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Posted by Peter Alberer on
Assessment is not doing an explicit lock anywhere, it is the foreign keys on the cr_items/cr_revisions table that are causing problems. When inserting a new submission, there is a new revision in cr_revisions, which causes the corresponding entry in the cr_items table to be locked.

Despite the fact that i know how a deadlock can appear in general, i am not sure why it happens that often in the assessments package. When 2 users are submitting the same assessment in the same moment, where the questions are in the same order, why would there be a deadlock?