Re: New EXPLAIN option: ALL

Hi,

On May 15, 2019 7:20:34 AM PDT, David Fetter <david(at)fetter(dot)org> wrote:
>On Wed, May 15, 2019 at 09:32:31AM -0400, Tom Lane wrote:
>> David Fetter <david(at)fetter(dot)org> writes:
>> > I hope the patch is a little easier to digest as now attached.
>>
>> To be blunt, I find 500K worth of changes in the regression test
>> outputs to be absolutely unacceptable, especially when said changes
>> are basically worthless from a diagnostic standpoint.
>
>You're right, of course. The fundamental problem is that our
>regression tests depend on (small sets of) fixed strings. TAP is an
>alternative, and could test the structure of the output rather than
>what really should be completely inconsequential changes in its form.
>> There are
>> at least two reasons why this won't fly:
>>
>> * Such a change would be a serious obstacle to back-patching
>> regression test cases that involve explain output.
>>
>> * Some buildfarm members use nonstandard settings (notably
>> force_parallel_mode, but I don't think that's the only one).
>> We are *not* going to maintain variant output files to try to cope
>> with all those combinations. It'd be even more disastrous for
>> private forks that might have their own affected settings.
>
>Indeed. I think we should move our regression tests to TAP and
>dispense with this.

-inconceivably much

The effort to write tap tests over our main tests is much much higher. And they're usually much slower. Of course tap is more powerful, so it's good to have the option.

And it'd be many months if not years worth of work, and would make backpatching much harder.

Andres
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