Date: Fri, 4 Mar 2016 15:41:57 -0300
From: Alvaro Herrera <alvherre@2ndquadrant.com>
To: Fabien COELHO <coelho@cri.ensmp.fr>
Cc: Michael Paquier <michael.paquier@gmail.com>,
	"pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>
Subject: Re: pgbench stats per script & other stuff
Message-ID: <20160304184157.GA726930@alvherre.pgsql>
MIME-Version: 1.0
Content-Type: text/plain; charset=iso-8859-1
Content-Disposition: inline
Content-Transfer-Encoding: 8bit
In-Reply-To: <alpine.DEB.2.10.1603041921320.11128@sto>
User-Agent: Mutt/1.5.23 (2014-03-12)
Precedence: bulk
Sender: pgsql-hackers-owner@postgresql.org

Fabien COELHO wrote:

> >However, this is still a bit broken -- you cannot return a stack
> >variable from process_file, because the stack goes away once the
> >function returns.  You need to malloc it.
> 
> That is why the "fs" variable in process_file is declared "static", and why
> I wrote "some hidden awkwarness".
> 
> I did want to avoid a malloc because then who would free the struct?
> addScript cannot to it systematically because builtins are static. Or it
> would have to create an on purpose struct, but I then that would be more
> awkwarness, and malloc/free to pass arguments between functions is not
> efficient nor very elegant.
> 
> So the "static" option looked like the simplest & most elegant version.

Surely that trick breaks if you have more than one -f switch, no?  Oh, I
see what you're doing: you only use the command list, which is
allocated, so it doesn't matter that the rest of the struct changes
later.  That seems rather nasty to me -- I'd avoid that.

I'm not concerned about freeing the struct; what's the problem with it
surviving until the program terminates?  If somebody specifies thousands
of -f switches, they will waste a few bytes with each, but I'm hardly
concerned about a few dozen kilobytes there ...

-- 
Álvaro Herrera                http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services


-- 
Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-hackers