Changes to the TASM AMP Worker Task Event in Teradata 13.10 - comment by carrie

Requests are different from tasks.  The request comes from the user within a user session.  One request can be sumitted through a session at one time.  
 
Usually, each AMP will use from 1 to 2 tasks to support it's work on behalf of one request.   Most user work that enters Teradata is all AMP work, so each AMP will have at least one task (possibly 2) working in parallel on behalf of the same query.  So having more AMPs does not mean you get to run more requests in parallel, unless you are doing single-AMP access only.  Having more AMPs means the work of a query step is divided across more AMPs and more parallelized.
 
All 80 AMP worker tasks on an AMP are rarely used at the same time.  Generally, with 80 AWTs per AMP, you will never see more than 62 AWTs active supporting user work.  This is because there are reserve pools that are holding back some number of those AWTs for special, internal purposes.  So if you assume each of the active requests are using 2 AWTs per AMP, then you could be supporting 31 requests at the same time if they were all-AMP requests.    More commonly you have a mix of requests some that require 1 AWT per AMP and others that require 2 AWTs per AMP.  In that case you could see anywhere from 45 to 60 requests actually executing at the same time.  Of course, there could be many other requests in the process of executing that don't happen to be running in the AMPs at that point in time, that have steps that are waiting to get an AWT on one AMP or another, or that are waiting in a throttle delay queue to start executing.
 
Thanks, -Carrie