Concurrency

SQL access to any object is subject to locking/latching issues. External programs have no need for any lock/latch, and more than one process can access the same memory region at the same time. This yields a higher level of concurrency. On the other hand, SQL access at rapid speed may increase the contention for specific latches (i.e., the row cache or library cache latches), and this overhead can be quite high in Real Application Clusters (RAC) environments.