SAP ASE version 15.7 and later includes a threaded kernel and a process kernel.
Threaded mode – SAP ASE runs as a single multithreaded operating system process, and processes SQL queries with engines running on threads in thread pools. Threaded mode utilizes threads without engines to manage I/O. Administrators can configure additional thread pools to manage workload.
Process mode – SAP ASE runs as multiple operating system processes that cooperate to work as a single server. Process mode uses engines to manage I/O, and administrators configure engine groups to manage workload.
For many workloads, threaded mode uses significantly less CPU than process mode, delivering the same—or better—performance. Threaded mode does not require as much task-to-engine affinity, thereby delivering more consistent performance in a mix of I/O- and CPU-intensive workloads.
The threaded kernel allows SAP ASE to take advantage of parallel hardware and support systems that have more processors, processor cores, and hardware threads than earlier-version kernels.
Although version 15.7 changes the kernel, the query processor remains the same. To run in threaded kernel mode, you need not change most scripts written for earlier versions of SAP ASE, although few commands and stored procedures have changed. Applications are completely compatible with threaded mode.