Re: wrong query results on bf leafhopper - Mailing list pgsql-hackers

From Robins Tharakan
Subject Re: wrong query results on bf leafhopper
Date
Msg-id CAEP4nAy6vctGY0p0pXk8V8oEgYa3xa5W2JgzGL=k_xJAtNi2XA@mail.gmail.com
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In response to Re: wrong query results on bf leafhopper  (David Rowley <dgrowleyml@gmail.com>)
Responses Re: wrong query results on bf leafhopper
List pgsql-hackers

On Tue, 20 May 2025 at 15:20, David Rowley <dgrowleyml@gmail.com> wrote:
On Tue, 20 May 2025 at 16:07, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> Failures like this one [1]:
>
> @@ -340,9 +340,13 @@
>  create function myinthash(myint) returns integer strict immutable language
>    internal as 'hashint4';
>  NOTICE:  argument type myint is only a shell
> +ERROR:  ROWS is not applicable when function does not return a set
>
> are hard to explain as anything besides "that machine is quite
> broken".  Whether it's flaky hardware, broken compiler, or what is
> undeterminable from here, but I don't believe it's our bug.  So I'm
> unexcited about putting effort into it.

There are certainly much fewer moving parts in PostgreSQL code for
that one as this failure doesn't seem to rely on anything stored in
any tables or the catalogues.

I'd have thought it would be unlikely to be a compiler bug as wouldn't
that mean it'd fail every time?


Recently leafhopper failed again on the same test. For now I've paused it.
To rule out the compiler (and its maturity on the architecture), I'll upgrade
gcc (to nightly, or something more recent) and then re-enable to see if it
changes anything.

I didn't dive in deeper but I see that indri failed recently [1] on what seems
like the exact same test / line-number (at t/027_stream_regress.pl line 95)
that leafhopper has been tripping on recently. The error is not verbatim,
but it was a little too coincidental to not highlight here.

-
robins

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