New Adaptive Server Kernel

Adaptive Server version 15.7 and later includes two kernels: a threaded kernel and a process kernel.

The kernel for which you configure Adaptive Server determines the mode in which Adaptive Server runs:

Threaded mode – Adaptive Server 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 – The legacy kernel on which Adaptive Server previously ran. In process mode, Adaptive Server 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 Adaptive Server 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 Adaptive Server, although few commands and stored procedures have changed. Applications are completely compatible with threaded mode.

Threaded mode is the default mode for Adaptive Server, and the mode that Sybase^® recommends. Adaptive Server on the Windows platform runs only in threaded mode.

See the System Administration Guide: Volume 2 for information about configuring Adaptive Server for threaded mode.