Developer discussion for Creative Commons technology and tools

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Bugs item #2728181, was opened at 2009-04-03 05:22
Message generated for change (Settings changed) made by fourstones
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Category: cchost
Group: None
>Status: Closed
Resolution: Fixed
Priority: 5
Private: No
Submitted By: Markus (mafu_)
Assigned to: Victor Stone (fourstones)
Summary: Race condition in uploads

Initial Comment:
When multiple users upload media at the same time, it's possible that a race 
conditions occurs. The problem lies with the NextID()-method in the class 
CCTable , which simply gets the next available auto_increment from the 
database. So if two users call NextID() concurrently, they get the same ID 
back, but only one can insert into the database with that ID -- the other 
user gets a MySQL error about a duplicate entry.

We have currently fixed this with a hack, locking the required tables before 
the insert (in cc-uploadapi.php), but really the row should be inserted 
first, the ID gotten with mysql_insert_id, which can then be used in the rest 
of the code.

Regards

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Comment By: Victor Stone (fourstones)
Date: 2009-04-22 15:23

Message:
checked in svn #12354

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You can respond by visiting: 
https://sourceforge.net/tracker/?func=detail&atid=559966&aid=2728181&group_id=80503