Analysis Services and the Windows File System Cache
In my last post I revealed a problem one of our customers ran into, where their SSAS memory limits had been inadvertently set to KB instead of bytes, leading to abnormally low limits and some pretty serious performance issues. I alluded to a “saving grace” that prevented things from being much worse than they were, and that’s what I’ll cover in this post.
A little background first, or rather an expansion of something I touched on in my original post on this issue -- unlike the SQL Server Database Engine, much of the SSAS data can be resident in memory by virtue of the Windows file system cache. This is simply because SSAS databases consist of a collection of Windows files of various types, and SSAS does not directly manage memory/disk access to those files using Windows APIs as “complex” memory managers like SQL Server do.
Tags: performance, memory