Tom Lane wrote:
Martijn van Oosterhout <kleptog@svana.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
http://phpadsnew.com
http://phppgads.com
---------------------------(end of broadcast)---------------------------
TIP 9: In versions below 8.0, the planner will ignore your desire to
choose an index scan if your joining column's datatypes do not
match
