SAP SE
Optimization of non-exclusive access database consistent change

Abstract:

A request is received for a first non-exclusive lock to read a page in a database. Thereafter, execution of the at least one non-exclusive lock is initiated. Later, a request for an exclusive lock to modify the page in the database is received. Subsequently, a request is received for a second non-exclusive lock. In response, an amount of time to finish the first request and the second request is estimated. The second non-exclusive lock is allowed to execute in parallel to the first non-exclusive if the determined amount of time to finish the second non-exclusive lock is less than an estimated amount of time needed by the first non-exclusive lock. Alternatively, execution of the second non-exclusive lock is delayed to after the execution of the exclusive lock if the determined amount of time to finish the second non-exclusive lock is greater than an amount of time needed by the first non-exclusive lock.