Re: Hide 'Execution time' in EXPLAIN (COSTS OFF)

Andres Freund <andres(at)2ndquadrant(dot)com> writes:
> On 2014-10-16 10:06:59 -0400, Tom Lane wrote:
>> No, it wasn't. I'm not convinced either that that patch will get in at
>> all, or that it has to have regression tests of that particular form,
>> or that such a switch would be sufficient to make such tests platform
>> independent.

> Why should the EXPLAIN ANALYZE output without timing information be less
> consistent for sensibly selected cases than EXPLAIN itself?

To take just one example, the performance numbers that get printed for
a sort, such as memory consumption, are undoubtedly platform-dependent.
Maybe your idea of "sensibly selected cases" excludes sorting, but
I don't find such an argument terribly convincing. I think if we go
down this road, we are going to end up with an EXPLAIN that has one
hundred parameters turning on and off tiny pieces of the output, none
of which are of any great use for anything except the regression tests.
I don't want to go there. It would be a lot better to expend the effort
on a better regression testing infrastructure that wouldn't *need*
bitwise-identical output across platforms. (mysql is ahead of us in that
department: they have some hacks for selective matching of the output.)

regards, tom lane