fabrizio.ermini@sysdat.it writes:
> All this figures confuse me. Which one should i use for
> comparison?
The reading of your stopwatch ;-)
The first line's "cost" value is the system's attempt to estimate total
runtime, but it would be foolish to take this as gospel. Especially so
with a pre-7.0 release, as I see you are using. There's a number of
problems with cost estimation in old releases, the biggest one for this
example being that SubPlan costs don't get factored into the outer
plan's cost.
regards, tom lane