If you go into DSNLINK, and look up in the OPENVms database, the article
entitled: "Explanation Of Dynamic Lock Re-Mastering And PE1 Parameter", you
will find information about how VMS locking under vms 5.5 through 6.1
determined which lock tries to migrate or not.  I would share the article with
the public, but I'm unsure about the copyright.

The basic idea is that lock migration occurs when lock activity on a node that
is not mastering the lock tree exceeds the lock activity on the node that is
mastering the tree.  This is an exceprt from the artical about how lock
activity is computed:

"
          Each local nodes records its lock activity.  The total
          activity over the last second is accumulated every second.
          The accumulation formula is:

               act = (8 * act) - 8 (( act - new) / 8 )

               act = previously computed activity
               new = new activity over the last second

     The above formula while confusing, basically takes the previous
     activity into account.
"

What was important to me, in using the RSB_CHAIN utility, was determining the
amount of activity of the lock tree.  By frequently gathering and recording the
activity of all the lock trees on all the nodes in the cluster, it was possible
to identify which lock tree throughout the day were most active.  And hence,
which locks were the source of a significant amount of MP_SYNCH time.  Once the
locks were identified, it was possible to determine the resource in question,
and the application that caused the locking.

At the site for which the RSB_CHAIN and associcated utilities were initially
written, it turned out that more than 80% of the locking activity was due to
RMS activity on a single file.  During online hours, the file was only read. 
However, programs were written in VMS Basic and openned the file for update. 
Changing the program to open the file for input only, and using the USER OPEN
option to clear the MSE bit, eliminated ALL of the locking activity on the
file.  RMS does not perform locking of records when the file is openned for
READ, allowing only readers, and with the Multi-Stream bit clear.

Feel free to contact me to discuss this issue and how it may apply to your
site.  You may reach me at GARRY@GFRUTHCONSULTING.COM
