Re: pgbench's expression parsing & negative numbers

From: Fabien COELHO <coelho(at)cri(dot)ensmp(dot)fr>
To: Andres Freund <andres(at)anarazel(dot)de>
Cc: pgsql-hackers(at)postgresql(dot)org
Subject: Re: pgbench's expression parsing & negative numbers
Date: 2017-12-14 22:47:57
Message-ID: alpine.DEB.2.20.1712142331140.5980@lancre
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Hello,

>> - I do not think that updating pgbench arithmetic for managing integer
>> overflows is worth Andres Freund time. My guess is that most
>> script would not trigger client-side overflows, so the change would
>> be a no-op in practice.
>
> It might not be if you view it in isolation (although I'm not
> convinced). The problem is that it has cost beyond pgbench. Due to
> pgbench's overflow handling

Lack of?

> I can't run make check on a build that has -ftrapv, which found several
> bugs already.

Hmmm. You suggest that integer overflows do occur when running pgbench.

Indeed, this tap test case: "\set maxint debug(:minint - 1)"

Otherwise, some stat counters may overflow on very long runs? Although
overflowing a int64 takes some time...

> I'd be happy if somebody else would tackle the issue, but I don't quite
> see it happening...

I must admit that it is not very high on my may-do list. I'll review it if
it appears, though.

--
Fabien.

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