Preemptive processes allow your applications to take full advantage of multi-core computers, resulting in faster responses to simultaneous requests. Beginning with 4D v17 R4, Begin SQL, End SQL, and the associated SQL statements used with an internal database are now preemptive compliant.
Before ORDA, many developers used Begin SQL and End SQL to work on a table without changing the current record. We’ve improved these commands to help you migrate your applications to preemptive mode. For example, if you use these commands to do a lot of asynchronous writings in your database, you can now start all your requests in parallel and increase the speed of your applications.
In the video below, you can see that preemptive mode increases the speed of your queries because all of the processors are engaged: