October 30, 2010 at 9:16 am
I am a DBA who is now in charge of an SSAS instance. That is cool.
Anyways, I know a lot of the answers to this might be "it depends", but I am trying to wrap my head around what I should be seeing. We have one small (15.5GB) AS database/cube. SSAS sits on a server by itself and is populated from a relational store on another server.
I am observing performance on the AS box during database processing. Based on what I have read, at points during processing, I would expect to see processor utilization on the AS box almost topped out. The box is very powerful, newest generation procs, 32 logical threads. I see a max of 20% proc utilization throughout.
Am I working off of a valid assumption that is proc utilization is not near 100% on the AS box than something is not running as efficiently as it should be? That is what I gleaned from a umber of different sources.
After reading a number of documents including an SSAS perf whitepaper from MS, I have been tinkering with thread count and still am not seeing the results I want. For example, the "processing pool busy thread" counter, seems to hover between 1 and 4. AS is only using a max of 4 threads?
I guess my expectation is that on a box of this size, AS would seriously light up all the procs/available threads and just tear through the processing. Not seeing that.
Thoughts?
October 30, 2010 at 9:48 am
It should be noted that we are telling AS to do the process in parallel and I am certain RAM is fine and we are not spilling out into temp space on disk.
During some parts of the process (index builds for example) I do see I/O write spikes to 30 - 35ms, but overall we are averaging under 20ms. Not ideal, but for a DW process, I am fine with it.
Just amazed that AS does not appear to be using all the resources available to it.....
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