Hi, I'm pretty new to Django and am having a problem with a race conditions while modifying my session data. I'm using the standard session backend in Django 1.4.1,, backed by Mysql.
I have view A, which can take a long time to process, and view B, which is usually faster. I store multiple data fields, fieldA and fieldB, in the session dictionary. View A modifies fieldA, and view B modifies fieldB. Sometimes, view A starts up with a copy of the session data as it exists at t1. Then, while it's processing, view B starts up. It completes quickly, modifying fieldB in the session data at time t2. Then view A finally completes, modifying its field in the session data at time t3. But what I wind up with is fieldA at time t3 and fieldB at time t1. In other words, when view A completes its write, it's storing the stale version of fieldB that it read when it started. What I want in that situation is t3's version of fieldA and t2's version of fieldB. My questions: (1) is there a way to check if your copy of the session dictionary is stale? And if so, is there a way to do it atomically? (2) Is there a way to selectively write just part of the session data, instead of the whole thing? (3) Or, is there a better solution besides either of these ideas? The only thing I can think of using RAM memory to keep track of a last_write timestamp for each session -- but that's not a scalable solution. Is there a better way? Thanks in advance, Spork -- You received this message because you are subscribed to the Google Groups "Django users" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/django-users?hl=en. For more options, visit https://groups.google.com/groups/opt_out.
