Jaime Casanova <jcasanov@systemguards.com.ec> writes:
> On Mon, Apr 26, 2010 at 3:03 PM, Robert Haas <robertmhaas@gmail.com> wrote:
>> On Mon, Apr 26, 2010 at 3:36 PM, Kevin Grittner
>> <Kevin.Grittner@wicourts.gov> wrote:
>>> I would use EXPLAIN ANALYZE SELECT ...
>>
>> There's some overhead to that, of course.
> he could see the "actual time" in the very first row of the EXPLAIN
> ANALYZE... isn't that a value that is more close to what the OP is
> looking for?
Well, it will include the instrumentation overhead of EXPLAIN ANALYZE,
which can be nontrivial depending on your hardware and the query plan.
On the other hand, EXPLAIN skips the cost of converting the result data
to text form, not to mention the network overhead of delivering it; so
in another sense it's underestimating the work involved.
I guess the real question is exactly what the OP is hoping to measure
and why.
regards, tom lane