Re: pgbench stats per script & other stuff - Mailing list pgsql-hackers

From Alvaro Herrera
Subject Re: pgbench stats per script & other stuff
Date
Msg-id 20160304184157.GA726930@alvherre.pgsql
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In response to Re: pgbench stats per script & other stuff  (Fabien COELHO <coelho@cri.ensmp.fr>)
Responses Re: pgbench stats per script & other stuff
List pgsql-hackers
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



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