Generated explain plan of a query in db2 11.5. Received the following output:
Estimated Cost = 22.776293 Estimated Cardinality = 0.000000
What is the unit of Estimated Cost in the output of db2expln command? Is it in seconds?
See here for the definition and explaination of costs.
A timeron is an invented relative unit of measurement. Timeron values are determined by the optimizer, based on internal values such as statistics that change as the database is used. As a result, the timeron values for an SQL or XQuery statement are not guaranteed to be the same every time an estimated cost in timerons is determined.
The above is for the total costs, but the explain should also show estimates for number of page I/Os, communication frames, CPU, etc.