Re: pgbench stats per script & other stuff

Fabien COELHO <coelho@cri.ensmp.fr>

From: Fabien COELHO <coelho@cri.ensmp.fr>
To: Michael Paquier <michael.paquier@gmail.com>
Cc: "pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>
Date: 2015-12-15T11:41:44Z
Lists: pgsql-hackers
>> "sum" is a double so count is converted to 0.0, 0.0/0.0 == NaN, hence the
>> comment.
>
> PG code usually avoids that, and I recall static analyze tools type
> coverity complaining that this may lead to undefined behavior. While I
> agree that this would lead to NaN...

Hmmm. In this case that is what is actually wanted. If there is no 
transaction, the tps or average latency or whatever is "NaN", I cannot 
help it, and IEEE 754 allow that. So in this case the tool is wrong if it 
complains, or at least we are right to ignore the warning. Maybe there is 
some special comment to say "ignore this warning on the next line" if it 
occurs, if this is an issue.

-- 
Fabien.


Commits

  1. pgbench: Allow changing weights for scripts