Re: Does EXPLAIN ANALYZE show a wrong plan for MIN/MAX?

Tom Lane wrote:
> Martijn van Oosterhout <kleptog(at)svana(dot)org> writes:
>> On Fri, Nov 11, 2005 at 11:05:45AM +0100, Matteo Beccati wrote:
>>> It seems that the plan outputted is not the optimized one (available
>>> since 8.1) that is really used when running the plain query.
>
>> It may also be that the overhead of calling gettimeofday() several
>> times per tuple is blowing the time out. What platform is this?
>
> Martijn's explanation is by far the more probable. The high overhead
> of EXPLAIN ANALYZE has been documented before.

OK, I've had the same explaination on IRC by dennisb, but I thought it
was strange to have a 15x slowdown.

So, does benchmarking queries using explain analyze lead to unreliable
results? Shouldn't a min/max query use a index scan when possible?

Best regards
--
Matteo Beccati
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