In the previous recipe, we discussed how to use different explain utilities. db2exfmt
is the most commonly-used utility for troubleshooting a performance problem. This utility gives very detailed information captured in EXPLAIN
tables in the form of an ASCII text report. This report contains textual information, as well as the access plan in a graphical format, which is extremely useful for query analysis. In this recipe, we will discuss how to interpret the results from the db2exfmt
utility.
As mentioned in the previous recipe, the output of the db2exfmt
tool contains very detailed information about the query execution plan. In this section, we will discuss how to interpret each section.