page lock promotion HWM and row lock promotion HWM set a maximum number of page or row locks allowed on a table before Adaptive Server attempts to escalate to a table lock. The default value is 200.
When the number of locks acquired during a scan session exceeds this number, Adaptive Server attempts to acquire a table lock.
Setting the high water mark to a value greater than 200 reduces the chance of any task or worker process acquiring a table lock on a particular table. For example, if a process updates more than 200 rows of a very large table during a transaction, setting the lock promotion high water mark higher keeps this process from attempting to acquire a table lock.
Setting the high water mark to less than 200 increases the chances of a particular task or worker process acquiring a table lock.