More on ResUsageSAWT When Collection and Logging Rates Differ - comment by carrie

Hi Pierre,
 
 
 
Starting in 14.0 and up, there is no longer a CollectIntervals column in any ResUsage table.  In the ResusageSAWT table,  MailBoxDepth and WorkTypeInUse00-15 are now track fields and no longer needs to be divided by the CollectIntervals column. The contents in those fields represent a snapshot taken at the end of the logging interval.  In prior releases the contents of those fields represented a sum of snapshots taken at the end of each collect interval.  So you had to divide by collectintervals in order not to get an inflated number.  You no longer are required to do that.
 
The 14.0  AMP Worker Task and ResUsage Monitoring orange book (available at Teradata at your service) documents this in Chapter 8.
 
When it comes to AMP worker tasks monitoring, I usually prefer to look at max of Inusemax rather than the average, so I can see what the worst case AWT usage is on any one AMP (either on the node or systemwide).  The worst case is usually more important than the average because if one AMP runs out of AWTs, it will impact all queries doing all-AMP operations.  In that regard max of inusemax is more actionable than is the average.  It will also allow you to more easily identify skewed processing on a node (where one or more AMPs on the node are holding on to AWTs longer than AMPs on other nodes).  But it really depends what you want to get out of the monitoring.   There is no one right way to use this information.
 
Thanks, -Carrie