Determining whether queries are I/O- or processor-intensive

How Db2 can a best take advantage of parallel processing for a particular query depends upon whether the query is I/O- or processor-intensive.

Procedure

To determine whether sequential queries are I/O or processor-intensive:

Examine the Db2 accounting reports:
  • If the other read I/O time is close to the total query elapsed time, then the query is I/O-intensive. Other read I/O time is the time that Db2 is waiting for pages to be read in to the buffer pools.
  • If CPU time is close to the total query elapsed time, then the query is processor-intensive.
  • If the processor time is somewhere in the range 30–70 percent of the elapsed time, then the query is pretty well-balanced in terms of CPU and I/O.