Zombie gem can hold commit record, cause CR backlog
When a session has logged out or been terminated, the stone normally waitsuntil it receives confirmation that the associated process is gone before
clearing the session's reference to a commit record. Under rare conditions
it is possible for the stone to miss this confirmation, causing the
"zombie" gem to continue holding the commit record and causing a commit
record backlog to develop that cannot be cleared.
You can confirm you have a zombie session causing a commit record backlog
when "System sessionsReferencingOldestCr" returns an array containing
a session ID that does not appear in "System currentSessions". Using System>>descriptionOfSession:
on this ID returns an array of nils.
Workaround:
For version 2.3 and earlier, you will need to shutdown and restart the
stone to clear the condition. For version 2.3.1 and later, login as SystemUser
and execute:
System _cleanupZombieSession: <sessionId>
Warning: make sure that this session really is a zombie. Use of this
command on a session that is still alive will cause that session's current
transaction to fail.