[rt-users] fatal error: RT3.0.12 hangs in an mySQL endless loop when creating user - have to restart Apache to proceed

[Alex Meier]

I have a problem which makes RequestTracker effectively unusable:
I set up RT on my Debian Sarge using apt-get install, configured and run 
it. Everything seemed to be ok, I could create users, queues, tickets, 
could reply to tickets and so on. The E-mail interface was also 
configured. Everything fine so far.

But now after a few days of basic testing I wanted to add another user. 
Trying to submit the newly entered user, RT hangs. When I look at the 
mysql.log file, I can see that RT is firing over and over again (about 
100 times per second) the following query:

  SELECT  * FROM CachedGroupMembers WHERE Disabled = '0' AND GroupId = 
'4' AND MemberId = '1'

which yields an empty set.
No chance to use the RT from this point on. CPU on my web server is on 
approx. 80% Apache, and the database server is facing the massive attack 
of queries.
The only cure: stop Apache, then restart it. I cannot create the user, 
every try leads to the described behaviour.

My system:
  - Debian Sarge
  - MySQL 4.0.24
  - Request Tracker 3.0.12

Any ideas?

Andi