Trac error: OperationalError: (1213, 'Deadlock found when trying to get lock; try restarting transaction')

[Jesse Glick]

Clicked Log In link on bug tracker for the first time in a while. Went thru Oracle SSO successfully. Was prompted to reuse an existing nickname, which I did. Then got this error. However I seem to be logged in now.

How to Reproduce

While doing a POST operation on /login, Trac issued an internal error.

(please provide additional details here)

Request parameters:

{'__FORM_TOKEN': u'[REDACTED]',
 'nick': u'jglick',
 'password': u'[REDACTED]',
 'referer': u'https://login.oracle.com/mysso/signon.jsp'}

User agent: Mozilla/5.0 (X11; Linux i686) AppleWebKit/536.11 (KHTML, like Gecko) Ubuntu/12.04 Chromium/20.0.1132.47 Chrome/20.0.1132.47 Safari/536.11

System Information

System information not available

Enabled Plugins

Plugin information not available

Python Traceback

Traceback (most recent call last):
  File "/usr/lib/python2.4/site-packages/trac/web/main.py", line 513, in _dispatch_request
    dispatcher.dispatch(req)
  File "/usr/lib/python2.4/site-packages/trac/web/main.py", line 235, in dispatch
    resp = chosen_handler.process_request(req)
  File "/usr/lib/python2.4/site-packages/trac/web/auth.py", line 117, in process_request
    self._redirect_back(req)
  File "/usr/lib/python2.4/site-packages/trac/web/auth.py", line 341, in _redirect_back
    req.redirect(referer or req.abs_href())
  File "/usr/lib/python2.4/site-packages/trac/web/api.py", line 358, in redirect
    self.session.save() # has to be done before the redirect is sent
  File "/usr/lib/python2.4/site-packages/trac/web/session.py", line 88, in save
    @self.env.with_transaction()
  File "/usr/lib/python2.4/site-packages/trac/db/api.py", line 77, in transaction_wrapper
    fn(ldb)
  File "/usr/lib/python2.4/site-packages/trac/web/session.py", line 144, in delete_session_cookie
    cursor.execute("""
  File "/usr/lib/python2.4/site-packages/trac/db/util.py", line 65, in execute
    return self.cursor.execute(sql_escape_percent(sql), args)
  File "/usr/lib64/python2.4/site-packages/MySQLdb/cursors.py", line 166, in execute
    self.errorhandler(self, exc, value)
  File "/usr/lib64/python2.4/site-packages/MySQLdb/connections.py", line 35, in defaulterrorhandler
    raise errorclass, errorvalue
OperationalError: (1213, 'Deadlock found when trying to get lock; try restarting transaction')