Error explaination?

Folks,
I have a fuction that creates a record in a table called user_locks,
does a bunch of stuff, then deletes the record.  However, when I try to
run it, I get the following error:

ERROR:  triggered data change violation on relation "user_locks"
It appears that the function handler won't let me create, then delete
the same record.  What goes on?

-Josh Berkus


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