joomla/joomla-platform — pull request #454 by garyamort (2011-10-21 12:05:23+00:00)
Title: Removed bug producing insert from JSessionStorageDatabase::write()

If update results in an error[such as a non existant row] then write will already return false. If however it succeeds but is identical to the current data, affectedRows will be 0, which then invokes insert while will ALWAYS fail because it is a duplicate row.

An insert is already performed when the session is created in JSession, there is no need for this one and it can only result in an error.