RE: DML on dual?

  • From: "Taft, David" <TaftD@xxxxxxxxxxx>
  • To: "'darrah.john@xxxxxxxxx'" <darrah.john@xxxxxxxxx>, Dave.Herring@xxxxxxxxxx
  • Date: Thu, 12 Apr 2007 15:29:56 -0400

Hmmm, my memory may not be serving me too well here, but this reminds me of
something I read in Tom Kyte's newest book.  I don't have the book with me,
so I can't look it up, but I think he had an example of some sort of
home-grown concurrency control mechanism.  Probably an example of how not to
code.  Anyway, I believe the example was such that a session had to hold
this lock for the code to proceed.  Darn, the one day I don't have that book
on hand. 
David Taft 

From: John Darrah [mailto:darrah.john@xxxxxxxxx] 

I've seen several oracle trace files that have the statement "SELECT 1 FROM
DUAL FOR UPDATE NOWAIT" I have no idea what the purpose of that statement is
but it probably explains what you are seeing.

Other related posts: