On Fri, Oct 28, 2022 at 10:43 AM Tom Lane <t...@sss.pgh.pa.us> wrote: > > David Rowley <dgrowle...@gmail.com> writes: > > On Fri, 28 Oct 2022 at 16:51, Amul Sul <sula...@gmail.com> wrote: > >> If we > >> are too sure that the output usually comes in the same order then the > >> ORDER BY clause that exists in other tests seems useless. I am a bit > >> confused & what could be a possible bug? > > > You can't claim that if this test shouldn't get an ORDER BY that all > > tests shouldn't have an ORDER BY. That's just crazy. What if the test > > is doing something like testing sort?! > > The general policy is that we'll add ORDER BY when a test is demonstrated > to have unstable output order for identifiable environmental reasons > (e.g. locale dependency) or timing reasons (e.g. background autovacuum > sometimes changing statistics). But the key word there is "identifiable". > Without some evidence as to what's causing this, it remains possible > that it's a code bug not the fault of the test case. > > regress.sgml explains the policy further: > > You might wonder why we don't order all the regression test queries > explicitly > to get rid of this issue once and for all. The reason is that that would > make the regression tests less useful, not more, since they'd tend > to exercise query plan types that produce ordered results to the > exclusion of those that don't. >
Understood. Thanks for the clarification. Regards, Amul
