What are HotSpots and ColdSpots?
A HotSpot is triggered when the GiAPA performance data collection (job GIAPAPFCOL) found a job that within an interval exceeded the CPU-% limit defined by the user when starting the data collection. Job GIAPAPFCOL passes the ID of the job exceeding the usage limits to job GIAPAHOTSP, which then collects the HotSpot data, consisting of call stack and file usage information for the job.
HotSpots are samples that only are taken whenever the CPU usage limit was exceeded. For jobs using that much resources repeatedly and thus causing many HotSpots, this sampling gets quite accurate, and will for any “heavy” job normally be a very reliable way of getting rather exact information about what the job was doing.
ColdSpots collects the same data as HotSpots, but are triggered by interactive jobs that use a little CPU without terminating a transaction within two consecutive collection intervals, typically seen in case of e.g. record lock conflicts. The automatic collection of the job call stack ensures that the program and statement where the job was waiting can be seen, thus revealing what the wait was caused by.