Re: Issues with ON CONFLICT UPDATE and REINDEX CONCURRENTLY

On 2025-Dec-12, Mihail Nikalayeu wrote:

> Hello, Álvaro!
>
> On Thu, Dec 11, 2025 at 10:36 PM Álvaro Herrera <alvherre(at)kurilemu(dot)de> wrote:
> > I just saw a failure in CI for an unrelated patch
>
> I'll try to dive deeper tomorrow to find a fix, but it feels like we
> are doing something wrong here.

Hmm, this is a good point.

> But currently we are just trying (not the first time already) to make
> sure OUTPUT of the test is EXACTLY equal to some variant.

A low-cost option might be to add alternative expected file(s), which
matches other variant(s). I think trying to make isolationtester "smart
match" the output might be more complicated than is warranted.

> I am afraid amount of time needed to stabilize such test (in its
> output, not the sense) is not cover potential value of it.

Yeah, could be.

> Also, I imaging someone changing something unrelated (catalog snapshot
> invalidation, for example) and test starts to fail on some rear animal
> once a week.... Ughn.

Another idea might be to rewrite these tests using BackgroundPsql under
the TAP infrastructure. That's quite a bit more tedious to write, but
we can be more precise on detecting whether some particular error
message was thrown or not.

--
Álvaro Herrera PostgreSQL Developer — https://www.EnterpriseDB.com/
"How amazing is that? I call it a night and come back to find that a bug has
been identified and patched while I sleep." (Robert Davidson)
http://archives.postgresql.org/pgsql-sql/2006-03/msg00378.php